Topic 6 · Solutions and separating mixtures — the scripts

What you are deciding: go-ahead for video generation on this topic, card by card.

Out of scope: articles and PP100 items (not on this page).

Here: the intro video, 9 lesson videos (2 marked by the author as “could do without a video”) and the summary video, in teaching order. Each card: the script, the attached question, then the quiz the student meets after the video.

How: tap one button per card. Taps and notes save as you go and are sent; the Notes tab shows what has gone and re-sends.

Intro video · teaches nothing, opens the question120 words · about 1:00

Introduction: Solutions and separating mixtures

Script
SayScreen
Here is a student making drinks in a kitchen.[a student at a kitchen counter; glasses and cups in front of her]
She stirs drink mix into one glass of water, and it vanishes; she stirs flour into another, and it clouds and settles.[the first glass colors evenly; the second clouds and settles]
She tops up a syrup drink with water, and it turns pale, yet no syrup was taken out.[a glass pales as water pours in]
She drops a sugar cube into hot water and one into cold, and the hot one is gone far sooner.[two cups; two timers; the hot cube shrinks first]
So what does dissolving make, what makes a drink stronger, and how can a mixture be taken apart again?[the glasses and cups in a row; question mark]
To find out, we will look at what happens when something dissolves, and how to take a mixture apart.[the counter stays]
Okay, so are you ready to find out where the drink mix went?[the three replies appear]

The ready line's poll — the attached item (no key; the intro teaches nothing)

video

Okay, so are you ready to find out where the drink mix went?

  1. A Yes, let's go! — Great. Here we go.
  2. B Not sure yet — That's fine. We take it one glass at a time.
  3. C Let me watch that again — Good idea. Watch it again, then come back.
Answer

No key. A poll: every reply is accepted with its friendly line.

Your note · the intro video
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 1 of 9Author: definitely a video199 words · about 1:40

A mixture made by dissolving: a solution

MAT-033 · Solution — Identify which mixtures are solutions based on whether one substance has dissolved evenly into another.

Script
SayScreen
A student stirs a packet of drink mix into a glass of water.[a glass of water; powder pours in; a spoon stirs]
The drink mix vanishes, and the water turns the same color all the way through.[the glass turns one even shade]
She stirs flour into a second glass; it turns cloudy, then the flour settles.[a second glass clouds; a layer forms at the bottom]
Both glasses hold mixtures, so why did only the drink mix seem to disappear?[both glasses; question mark over the first]
The drink mix dissolved, and the flour did not.[chip over the first glass: DISSOLVED]
Zoomed in on the drink mix glass, its particles are spread evenly among the water particles.[sample box: open drink mix particles spread among filled water particles]
Zoomed in on the flour glass, the flour particles are still stuck together in grains on the bottom.[sample box: clumps of open particles on the floor]
A mixture in which one substance has dissolved evenly into another is called a solution.[chip: SOLUTION]
Salt stirred into water vanishes and spreads evenly, so salt water is a solution.[question line A SOLUTION? above the cases; salt box; tick]
Pepper shaken into water floats and sinks and never vanishes, so it is not a solution.[pepper box with grains; cross]
Vinegar poured into water vanishes into it, so it is a solution, with no solid at all.[vinegar box; tick]
So, here's what we've seen. A mixture in which one substance has dissolved evenly into another is called a solution.[the rule slide: the drink mix box and the flour box with their tick and cross; chip SOLUTION; nothing else printed]
So the drink mix glass holds a solution, and the flour glass does not.[the two glasses; tick on the first, cross on the second]
Okay, now your turn.[the rule slide's images hold; closing screen: one line — “A mixture in which one substance has dissolved evenly into another is called a solution.”]

“Okay, now your turn.” — the attached question

video

Drink mix stirred into one glass of water vanishes and spreads evenly through it; flour stirred into another glass settles. Which glass holds a solution?

  1. A the drink mix glass
  2. B the flour glass
  3. C both glasses
Answer

Key: A — the drink mix glass

A mixture in which one substance has dissolved evenly into another is called a solution.
The drink mix dissolves evenly; the flour stays as grains.
So only the drink mix glass holds a solution.

Feedback per option

  • A The drink mix dissolves evenly into the water: a solution.
  • B The flour stays as grains and settles, so it does not dissolve.
  • C Only the drink mix dissolves. The flour glass holds a mixture that is not a solution.

Quiz after the video — the mastery check, 13 items

Q1recall

Sesame oil is drizzled into a bowl of soup and floats in golden beads on top. Is the soup now a mixture or a pure substance?

  1. A a mixture
  2. B a pure substance
Answer

Key: A — a mixture

The bowl holds oil and soup mingled together.
Two or more substances mingled together make a mixture.
So the soup is now a mixture.

Feedback per option

  • A The soup now holds two substances, oil and soup, mingled together.
  • B A pure substance is one kind of matter only. Oil and soup are two kinds.
Q2recall

A spoon of powdered sweetener stirred into iced tea vanishes and spreads through the tea. Did the sweetener dissolve?

  1. A yes
  2. B no
Answer

Key: A — yes

A substance dissolves when it breaks into particles too small to see and spreads through the liquid.
The sweetener vanished and spread through the tea.
So the sweetener dissolved.

Feedback per option

  • A The sweetener broke into particles too small to see and spread through the tea: that is dissolving.
  • B Vanishing and spreading through the liquid is what dissolving looks like.
Q3term

A mixture in which one substance has dissolved evenly into another is called a…

Typed answer

Answer

Accepted: solution · a solution

A mixture in which one substance has dissolved evenly into another is called a solution.
Q4term

A scientist calls a mixture a solution. What does she mean?

  1. A One substance has dissolved evenly into another.
  2. B The mixture is a liquid.
  3. C A solid has settled at the bottom.
Answer

Key: A — One substance has dissolved evenly into another.

A mixture in which one substance has dissolved evenly into another is called a solution.
Being a liquid is not the test, and a settled solid means no solution.

Feedback per option

  • A Zoom in, and the dissolved particles are spread evenly among the other particles.
  • B Many liquids are not solutions. A solution is made by dissolving.
  • C A settled solid did not dissolve, so that mixture is not a solution.
Q5fluency

Filled and open circles are two different kinds of particle. Is this liquid a solution?

  1. A yes
  2. B no
Answer

Key: A — yes

Look at where the open particles sit.
They are spread evenly among the filled particles.
One substance dissolved evenly into another makes a solution.

Feedback per option

  • A The open particles are spread evenly among the filled ones: one substance dissolved evenly into another.
  • B The open particles are spread evenly through the whole box, not gathered in grains.
Q6fluency

Iced-tea mix shaken into a bottle of water vanishes completely. Is the tea a solution?

  1. A yes
  2. B no
Answer

Key: A — yes

The mix vanished and spread evenly through the water.
Every gulp is the same.
One substance dissolved evenly into another makes a solution.

Feedback per option

  • A The mix dissolved evenly into the water.
  • B The mix vanished and every gulp is the same: it dissolved evenly.
Q7fluency

Bits of eggshell stirred into water sink and stay as bits. Is the mix a solution?

  1. A yes
  2. B no
Answer

Key: B — no

The eggshell bits stayed as bits and sank.
So the eggshell did not dissolve.
A mixture whose pieces stay pieces is not a solution.

Feedback per option

  • A The bits stayed bits and sank: the eggshell did not dissolve.
  • B The eggshell did not dissolve, so the mix is not a solution.
Q8fluency

Filled and open circles are two different kinds of particle. Is this liquid a solution?

  1. A yes
  2. B no
Answer

Key: B — no

Look at where the open particles sit.
They are stuck together in clumps on the floor of the box.
Grains that stay grains did not dissolve, so this is not a solution.

Feedback per option

  • A The open particles are stuck together in clumps on the floor: they did not dissolve.
  • B The open particles sit in clumps on the floor, not spread through the water.
Q9fluency

Rubbing alcohol poured into water vanishes into it. Is the mix a solution?

  1. A yes
  2. B no
Answer

Key: A — yes

The alcohol vanished into the water, and every drop of the mix is the same.
So the alcohol dissolved evenly into the water.
One substance dissolved evenly into another makes a solution.

Feedback per option

  • A The alcohol dissolved evenly into the water. A liquid can dissolve too.
  • B The alcohol vanished into the water and every drop is the same: it dissolved evenly.
Q10fluency

Cornstarch stirred into cold water clouds the water and then settles. Is the mix a solution?

  1. A yes
  2. B no
Answer

Key: B — no

The cornstarch clouded the water and then settled.
Its grains stayed grains, so the cornstarch did not dissolve.
A mixture whose grains settle is not a solution.

Feedback per option

  • A Clouding and settling means the cornstarch grains stayed grains.
  • B The cornstarch settled, so it did not dissolve, and the mix is not a solution.
Q11fluency

Filled and open circles are two different kinds of particle. Is this liquid a solution?

  1. A yes
  2. B no
Answer

Key: B — no

Look at where the open particles sit.
They are stuck together in two clumps: one part-way down, one on the floor.
Grains that stay grains did not dissolve, so this is not a solution.

Feedback per option

  • A The open particles are stuck together in two clumps: one is still sinking, and one sits on the floor. They did not dissolve.
  • B The open particles sit in two clumps, one sinking and one on the floor, not spread through the water.
Q12fluency

Bath salts dropped into a warm bath vanish into the water. Is the bath water a solution?

  1. A yes
  2. B no
Answer

Key: A — yes

The bath salts vanished and spread through the water.
So the salts dissolved evenly into the water.
One substance dissolved evenly into another makes a solution.

Feedback per option

  • A The bath salts dissolved evenly into the water.
  • B The salts vanished and spread through the water: they dissolved evenly.
Q13misconception

Aarav stirs sugar into lemonade until it vanishes. He says: "The sugar is gone now, so the lemonade has no sugar in it." Is Aarav correct?

  1. A yes
  2. B no
Answer

Key: B — no

Dissolving breaks the sugar into particles too small to see.
Those particles are spread evenly through the lemonade.
Every sip is sweet, so the sugar is still there, and Aarav is not correct.

Feedback per option

  • A Gone from sight is not gone. The sugar broke into particles too small to see and spread through the lemonade, so every sip is sweet.
  • B The sugar is still there as particles too small to see, spread through the lemonade, so every sip is sweet.
Your note · lesson 1: A mixture made by dissolving: a solution
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 2 of 9Author: could do without a video194 words · about 1:37

The two parts of a solution: solute and solvent

MAT-034 · Solute and solvent — Label the solute and solvent in a given solution.

Script
SayScreen
A recipe card for hummingbird nectar reads: dissolve fifty grams of sugar in two hundred milliliters of water.[the recipe card]
Two substances make this solution: one dissolves, and the other does the dissolving.[SUGAR and WATER highlighted on the card]
Which is which?[question mark]
The sugar dissolves, and the water does the dissolving.[arrow from SUGAR: dissolves; arrow from WATER: does the dissolving]
The sugar breaks into particles too small to see and spreads out among the water particles.[sample box: open sugar particles spreading among filled water particles]
The water spreads the sugar particles out, so the water does the dissolving.[the water particles jostle the sugar particles apart]
The substance that dissolves is called the solute.[chip: SOLUTE, under the sugar]
The substance the solute dissolves into is called the solvent.[chip: SOLVENT, under the water]
Solute plus solvent makes a solution.[solute + solvent → solution]
The solvent is usually a liquid, and there is usually more of it.[200 mL of water beside 50 g of sugar]
In soda water, the carbon dioxide gas is the solute, and the water is the solvent.[bottle; labels SOLUTE: gas, SOLVENT: water]
In sweet tea with honey, the honey is the solute, and the tea is the solvent.[cup; labels]
With food coloring in water, the coloring is the solute, and the water is the solvent.[jar; labels]
So, the substance that dissolves is called the solute. The substance it dissolves into is called the solvent.[the rule slide: the recipe card; chips SOLUTE under the sugar, SOLVENT under the water; nothing else printed]
So in the recipe, the sugar is the solute, and the water is the solvent.[the card with both labels]
Okay, now your turn.[the rule slide's images hold; closing screen: bullets — • The substance that dissolves is called the solute. • The substance it dissolves into is called the solvent.]

“Okay, now your turn.” — the attached question

video

In hummingbird nectar, sugar dissolves into water. Which one is the solute?

  1. A the sugar
  2. B the water
Answer

Key: A — the sugar

The substance that dissolves is called the solute.
The sugar dissolves into the water.
So the sugar is the solute, and the water is the solvent.

Feedback per option

  • A The substance that dissolves is the solute.
  • B The water does the dissolving, so the water is the solvent.

Quiz after the video — the mastery check, 14 items

Q1recall

Powdered lemonade stirred into water vanishes and spreads evenly through it. Is the lemonade a solution?

  1. A yes
  2. B no
Answer

Key: A — yes

A mixture in which one substance has dissolved evenly into another is called a solution.
The powder dissolved evenly into the water.
So the lemonade is a solution.

Feedback per option

  • A One substance dissolved evenly into another makes a solution.
  • B The powder dissolved evenly into the water, so the lemonade is a solution.
Q2term

In a solution, the substance that dissolves is called the…

Typed answer

Answer

Accepted: solute · the solute

The substance that dissolves is called the solute.
Q3term

In a solution, the substance the solute dissolves into is called the…

Typed answer

Answer

Accepted: solvent · the solvent

The substance the solute dissolves into is called the solvent.
Q4term

In a solution, which substance is the solvent?

  1. A the substance the solute dissolves into
  2. B the substance that does the vanishing
  3. C the substance there is less of
Answer

Key: A — the substance the solute dissolves into

The substance that dissolves is called the solute.
The substance it dissolves into is called the solvent.
There is usually more of the solvent.

Feedback per option

  • A The solvent does the dissolving, and the solute dissolves into it.
  • B The substance that vanishes into the other is the solute.
  • C There is usually less of the solute, not the solvent.
Q5term

In a solution, which substance is the solute?

  1. A the substance the other one dissolves into
  2. B the substance that dissolves into the other
  3. C the substance there is usually more of
Answer

Key: B — the substance that dissolves into the other

The substance that dissolves is called the solute.
It breaks into particles too small to see and spreads through the other substance.
There is usually less of the solute.

Feedback per option

  • A The substance the other one dissolves into is the solvent.
  • B The solute dissolves: it breaks into particles too small to see and spreads through the solvent.
  • C There is usually more of the solvent, not the solute.
Q6fluency

Instant coffee dissolves in a mug of hot water. Which is the solute?

  1. A the instant coffee
  2. B the hot water
Answer

Key: A — the instant coffee

The substance that dissolves is the solute.
The coffee dissolves into the water.
So the coffee is the solute.

Feedback per option

  • A The coffee dissolves, so the coffee is the solute.
  • B The water does the dissolving, so the water is the solvent.
Q7fluency

Carbon dioxide gas is dissolved in a bottle of sparkling water. Which is the solute?

  1. A the carbon dioxide gas
  2. B the water
Answer

Key: A — the carbon dioxide gas

The substance that dissolves is the solute.
The gas dissolved into the water.
So the gas is the solute, even though it is a gas.

Feedback per option

  • A The gas dissolved into the water, so the gas is the solute.
  • B The water does the dissolving, so the water is the solvent.
Q8fluency

Salt is dissolved in sea water. Which is the solvent?

  1. A the salt
  2. B the water
Answer

Key: B — the water

The substance the solute dissolves into is the solvent.
The salt dissolved into the water.
So the water is the solvent.

Feedback per option

  • A The salt dissolves, so the salt is the solute.
  • B The water does the dissolving, so the water is the solvent.
Q9fluency

Drink mix dissolves in a cup of hot milk. Which is the solvent?

  1. A the drink mix
  2. B the milk
Answer

Key: B — the milk

The substance the solute dissolves into is the solvent.
The drink mix dissolved into the milk.
So the milk is the solvent, even though it is not water.

Feedback per option

  • A The drink mix dissolves, so the drink mix is the solute.
  • B The milk does the dissolving, so the milk is the solvent.
Q10fluency

A drop of blue ink spreads through a jar of water. Which is the solute?

  1. A the ink
  2. B the water
Answer

Key: A — the ink

Ask which substance vanished into the other.
The ink vanished into the water.
So the ink is the solute.

Feedback per option

  • A The ink vanished into the water, so the ink is the solute.
  • B The water does the dissolving, so the water is the solvent.
Q11fluency

Laundry soap dissolves in a tub of water. Which is the solvent?

  1. A the soap
  2. B the water
Answer

Key: B — the water

The substance the solute dissolves into is the solvent.
The soap dissolved into the water.
So the water is the solvent.

Feedback per option

  • A The soap dissolves, so the soap is the solute.
  • B The water does the dissolving, so the water is the solvent.
Q12fluency

Oxygen gas is dissolved in a fish tank's water. Which is the solvent?

  1. A the oxygen
  2. B the water
Answer

Key: B — the water

The substance the solute dissolves into is the solvent.
The oxygen gas dissolved into the water.
So the water is the solvent.

Feedback per option

  • A The oxygen dissolved into the water, so the oxygen is the solute.
  • B The water does the dissolving, so the water is the solvent.
Q13fluency

A splash of vinegar vanishes into a big pitcher of water. Which is the solute?

  1. A the vinegar
  2. B the water
Answer

Key: A — the vinegar

Ask which substance vanished into the other.
The vinegar vanished into the water, and there is far less of it.
So the vinegar is the solute, even though both are liquids.

Feedback per option

  • A The vinegar vanished into the water, and there is far less of it: the solute.
  • B There is far more water, and it does the dissolving: the solvent.
Q14misconception

Hassan looks at a glass of salt water. He says: "The water is the solute, because water is a liquid." Is Hassan correct?

  1. A yes
  2. B no
Answer

Key: B — no

The substance that dissolves is the solute.
The salt dissolved into the water, so the salt is the solute.
The water did the dissolving, so the water is the solvent, and Hassan is not correct.

Feedback per option

  • A Being a liquid is not the test. The salt dissolved into the water, so the salt is the solute and the water is the solvent.
  • B The salt dissolved into the water, so the salt is the solute and the water is the solvent.
Your note · lesson 2: The two parts of a solution: solute and solvent
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 3 of 9Author: could do without a video199 words · about 1:40

How concentrated? More solute in the same solvent

MAT-035 · Concentration — Order solutions from most to least concentrated given the amounts of solute and solvent in each.

Script
SayScreen
Three mugs each hold two hundred milliliters of hot water.[three mugs; label 200 mL on each]
A student stirs five grams of instant coffee into the first, ten grams into the second, twenty grams into the third.[5 g, 10 g, 20 g spoon in; each stirred]
All the coffee dissolves, but the third mug is the darkest and strongest.[the mugs shade pale, darker, darkest]
What is different about the third mug?[question mark over the third mug]
It holds the most coffee in the same water.[chip over the third mug: MOST COFFEE, SAME WATER]
In every mug the coffee is the solute and the water is the solvent.[labels SOLUTE: coffee, SOLVENT: water]
The water is the same in every mug, but the third holds four times the coffee.[table: 5 g, 10 g, 20 g against 200 mL, 200 mL, 200 mL]
Each sip from the third mug carries more coffee, so it is stronger and darker.[a sip from each mug; more open particles in the third]
How much solute is dissolved in a given amount of solvent is called the concentration.[chip: CONCENTRATION]
More solute in the same solvent means more concentrated.[the table gains a column: most … least concentrated]
Two pitchers each hold thirty grams of sugar: one in a thousand milliliters of water, one in five hundred milliliters.[two pitchers; 30 g in each; 1,000 mL and 500 mL]
The pitcher with five hundred milliliters has the same sugar in less water, so it is more concentrated.[the 500 mL pitcher highlighted: MORE CONCENTRATED]
The same solute in more solvent means less concentrated.[the 1,000 mL pitcher: LESS CONCENTRATED]
So, more solute in the same solvent means more concentrated. The same solute in more solvent means less concentrated.[the rule slide: the mugs table with its most-to-least column; chip CONCENTRATION; nothing else printed]
Okay, now your turn.[the rule slide's images hold; closing screen: bullets — • More solute in the same solvent means more concentrated. • The same solute in more solvent means less concentrated.]

“Okay, now your turn.” — the attached question

video

Three mugs hold the same water, and the third mug holds the most coffee. Which mug is the most concentrated?

  1. A the first mug
  2. B the second mug
  3. C the third mug
Answer

Key: C — the third mug

The water is the same in every mug.
The third mug holds the most coffee.
More solute in the same solvent means more concentrated, so the third mug.

Feedback per option

  • A The first mug holds the least coffee in the same water: the least concentrated.
  • B The second mug holds less coffee than the third.
  • C More solute in the same solvent means more concentrated.

Quiz after the video — the mastery check, 12 items

Q1recall

Powdered plant food is dissolved in a can of water for a houseplant. Which is the solute?

  1. A the plant food
  2. B the water
Answer

Key: A — the plant food

The substance that dissolves is the solute.
The plant food dissolved into the water.
So the plant food is the solute.

Feedback per option

  • A The plant food dissolves, so the plant food is the solute.
  • B The water does the dissolving, so the water is the solvent.
Q2term

How much solute is dissolved in a given amount of solvent is called the…

Typed answer

Answer

Accepted: concentration · the concentration

How much solute is dissolved in a given amount of solvent is called the concentration.
Q3term

Two glasses hold the same amount of water, and one is called more concentrated. What does that mean?

  1. A It has more solute in the same water.
  2. B It holds more water than the other glass.
  3. C Its solute has settled to the bottom.
Answer

Key: A — It has more solute in the same water.

Concentration is how much solute is dissolved in a given amount of solvent.
The water is the same in both glasses.
So the more concentrated glass has more solute dissolved in it.

Feedback per option

  • A More solute in the same amount of solvent is a higher concentration.
  • B The two glasses hold the same water. Concentration is about the solute in that water.
  • C A settled solute has not dissolved. Concentration is about dissolved solute.
Q4fluency

Which bottle is more concentrated?

bottle Abottle Bsports drink mix10 g25 gwater250 mL250 mL
  1. A bottle A
  2. B bottle B
Answer

Key: B — bottle B

The water is the same: 250 mL in each bottle.
Bottle B holds 25 g of drink mix; bottle A holds 10 g.
More solute in the same solvent means more concentrated, so bottle B.

Feedback per option

  • A Both bottles hold 250 mL of water. Bottle A has less drink mix in it.
  • B Both bottles hold 250 mL of water, and bottle B has more drink mix in it.
Q5fluency

Which pot is more concentrated?

pot Apot Bsalt8 g8 gwater400 mL800 mL
  1. A pot A
  2. B pot B
Answer

Key: A — pot A

The salt is the same: 8 g in each pot.
Pot A holds 400 mL of water; pot B holds 800 mL.
The same solute in less solvent means more concentrated, so pot A.

Feedback per option

  • A Both pots hold 8 g of salt, and pot A has less water.
  • B Both pots hold 8 g of salt. Pot B spreads it through twice the water.
Q6fluency

Which cup is more concentrated?

cup Acup Bhoney15 g5 gwater300 mL300 mL
  1. A cup A
  2. B cup B
Answer

Key: A — cup A

The water is the same: 300 mL in each cup.
Cup A holds 15 g of honey; cup B holds 5 g.
More solute in the same solvent means more concentrated, so cup A.

Feedback per option

  • A Both cups hold 300 mL, and cup A has more honey in it.
  • B Both cups hold 300 mL. Cup B has less honey in it.
Q7fluency

Which thermos is more concentrated?

thermos Athermos Bhot chocolate mix20 g20 gwater1,000 mL400 mL
  1. A thermos A
  2. B thermos B
Answer

Key: B — thermos B

The mix is the same: 20 g in each thermos.
Thermos A holds 1,000 mL of water; thermos B holds 400 mL.
The same solute in less solvent means more concentrated, so thermos B.

Feedback per option

  • A Both thermoses hold 20 g of mix. Thermos A spreads it through far more water.
  • B Both thermoses hold 20 g of mix, and thermos B has less water.
Q8fluency

Which glass is more concentrated?

glass Aglass Bsweetener3 g1 gwater150 mL150 mL
  1. A glass A
  2. B glass B
Answer

Key: A — glass A

The water is the same: 150 mL in each glass.
Glass A holds 3 g of sweetener; glass B holds 1 g.
More solute in the same solvent means more concentrated, so glass A.

Feedback per option

  • A Both glasses hold 150 mL, and glass A has more sweetener in it.
  • B Both glasses hold 150 mL. Glass B has less sweetener in it.
Q9fluency

Which tank is more concentrated?

tank Atank Baquarium salt12 g12 gwater6,000 mL3,000 mL
  1. A tank A
  2. B tank B
Answer

Key: B — tank B

The salt is the same: 12 g in each tank.
Tank A holds 6,000 mL of water; tank B holds 3,000 mL.
The same solute in less solvent means more concentrated, so tank B.

Feedback per option

  • A Both tanks hold 12 g of salt. Tank A spreads it through twice the water.
  • B Both tanks hold 12 g of salt, and tank B has less water.
Q10fluency

Which jar is the most concentrated?

food coloringwaterjar A6 g300 mLjar B15 g300 mLjar C9 g300 mL
  1. A jar A
  2. B jar B
  3. C jar C
Answer

Key: B — jar B

The water is the same: 300 mL in every jar.
Jar B holds 15 g of coloring, more than jar C's 9 g or jar A's 6 g.
The most solute in the same solvent means the most concentrated, so jar B.

Feedback per option

  • A Every jar holds 300 mL. Jar A has the least coloring, 6 g.
  • B Every jar holds 300 mL, and jar B has the most coloring, 15 g.
  • C Every jar holds 300 mL. Jar C has 9 g, less than jar B.
Q11fluency

Which tub is the least concentrated?

bath saltwatertub A10 g500 mLtub B10 g200 mLtub C10 g800 mL
  1. A tub A
  2. B tub B
  3. C tub C
Answer

Key: C — tub C

The bath salt is the same: 10 g in every tub.
Tub C holds 800 mL of water, more than tub A's 500 mL or tub B's 200 mL.
The same solute in the most solvent means the least concentrated, so tub C.

Feedback per option

  • A Every tub holds 10 g of bath salt. Tub A has 500 mL, less water than tub C.
  • B Every tub holds 10 g. Tub B has the least water, so it is the most concentrated.
  • C Every tub holds 10 g of bath salt, and tub C has the most water, 800 mL.
Q12misconception

Keiko compares the small glass and the big pitcher. She says: "The pitcher is more concentrated, because it is bigger." Is Keiko correct?

the small glassthe big pitcherdrink powder5 g5 gwater100 mL1,000 mL
  1. A yes
  2. B no
Answer

Key: B — no

Concentration is how much solute is dissolved in a given amount of solvent.
The same 5 g of powder is spread through 1,000 mL in the pitcher and 100 mL in the glass.
The same solute in more solvent means less concentrated, so Keiko is not correct.

Feedback per option

  • A Bigger is not more concentrated. The same 5 g is spread through ten times the water in the pitcher, so the pitcher is less concentrated.
  • B The same 5 g is spread through ten times the water in the pitcher, so the pitcher is less concentrated.
Your note · lesson 3: How concentrated? More solute in the same solvent
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 4 of 9Author: definitely a video200 words · about 1:40

Adding water: diluting a solution

MAT-036 · Dilution — Predict what happens to the concentration of a solution when more solvent is added.

Script
SayScreen
A glass holds a dark, strong drink: forty grams of syrup in two hundred milliliters of water.[a dark glass; label 40 g of syrup, 200 mL of water]
A student tops the glass up to four hundred milliliters with more water.[water pours in; the level rises to a 400 mL line]
The color pales and the drink tastes weaker, yet no syrup was taken out.[the glass pales]
Why is the drink weaker?[question mark]
The same syrup is now spread through twice the water.[label 40 g in 400 mL]
The syrup is the solute and the water is the solvent.[labels SOLUTE: syrup, SOLVENT: water]
Before the extra water, zoomed in, the syrup particles sit close together among the water particles.[sample box: six open syrup particles among ten filled water particles]
After the water is added, every syrup particle is still there, spread through twice the water.[the box stretches to twice its width; the same six open particles spread out]
Each sip is the same size, but it carries fewer syrup particles.[a sip-sized circle over each box; fewer open particles inside the second]
So it tastes weaker, because the concentration has gone down.[chip: LESS CONCENTRATED]
Adding more solvent to a solution is called diluting it.[chip: DILUTING]
Diluting takes no solute away: all forty grams are still in the glass.[40 g stays on the label]
Salty soup filled up with water is diluted.[a pot; water pours in; label DILUTED]
Tea with more hot water poured in is diluted too.[a cup of tea pales; label DILUTED]
If she adds more syrup instead, the drink gets stronger, and that is not diluting.[syrup pours in; the glass darkens; cross over DILUTING]
So, adding more solvent to a solution is called diluting it, and the concentration goes down.[the rule slide: the before-and-after boxes; chip DILUTING; nothing else printed]
Okay, now your turn.[the rule slide's images hold; closing screen: one line — “Adding more solvent to a solution is called diluting it, and the concentration goes down.”]

“Okay, now your turn.” — the attached question

video

A student adds water to a syrup drink, and it turns paler. What happens to its concentration?

  1. A It goes down.
  2. B It goes up.
  3. C It stays the same.
Answer

Key: A — It goes down.

Adding more solvent to a solution is called diluting it.
The same syrup is spread through more water.
So the concentration goes down.

Feedback per option

  • A The same syrup spreads through more water: diluted, less concentrated.
  • B Adding water adds solvent, not solute, so the concentration cannot rise.
  • C The syrup is spread through more water, so each sip carries less.

Quiz after the video — the mastery check, 10 items

Q1recall

Two pitchers hold the same amount of water. Pitcher A has more sugar dissolved in it than pitcher B. Which pitcher is more concentrated?

  1. A pitcher A
  2. B pitcher B
Answer

Key: A — pitcher A

Concentration is how much solute is dissolved in a given amount of solvent.
The water is the same, and pitcher A has more sugar.
So pitcher A is more concentrated.

Feedback per option

  • A More solute in the same solvent means more concentrated.
  • B Pitcher B has less sugar in the same water, so it is less concentrated.
Q2term

Adding more solvent to a solution is called…

Typed answer

Answer

Accepted: diluting · diluting it · dilution · diluting the solution · dilute

Adding more solvent to a solution is called diluting it.
The concentration goes down.
Q3term

A student diluted a solution. What did she do to it?

  1. A She added more solute.
  2. B She took some solute out.
  3. C She added more solvent.
Answer

Key: C — She added more solvent.

Adding more solvent to a solution is called diluting it.
The same solute spreads through more solvent, so the concentration goes down.

Feedback per option

  • A Adding solute makes a solution more concentrated, not diluted.
  • B Diluting takes no solute out. It adds solvent.
  • C Adding more solvent is diluting; the concentration goes down.
Q4what

A glass holds 300 mL of apple juice. A student adds 300 mL of water and stirs. What happens to the concentration of the juice?

  1. A It goes down.
  2. B It goes up.
  3. C It stays the same.
Answer

Key: A — It goes down.

The student added solvent, not solute.
The same juice is now spread through twice as much liquid.
Each sip carries less juice, so the concentration goes down.

Feedback per option

  • A The same juice is spread through twice as much liquid.
  • B Adding water adds solvent, not solute, so the concentration cannot go up.
  • C The juice is spread through more water, so each sip carries less juice.
Q5why

A student adds 300 mL of water to 300 mL of apple juice and stirs. The juice now tastes weaker. Explain why.

Starter: The juice tastes weaker because…

Answer

Model answer · ['the same juice is spread through more liquid (no juice was taken out)', 'each sip carries less juice', 'so the concentration has gone down'] points

The juice tastes weaker because the same juice is now spread through twice as much liquid.
No juice was taken out.
Each sip carries less juice than before.
So the concentration has gone down, and the juice tastes weaker.
Q6misconception

Freya fills up a glass of dark fruit syrup drink with water, and it turns pale. She says: "The water washed some of the syrup away, so there is less syrup now." Is Freya correct?

  1. A yes
  2. B no
Answer

Key: B — no

Adding water adds solvent; it takes no solute away.
All the syrup is still in the glass, spread through more water.
Each sip carries less syrup, so the drink is paler, and Freya is not correct.

Feedback per option

  • A Water adds solvent; it washes no syrup away. All the syrup is still in the glass, spread through more water, so each sip carries less.
  • B All the syrup is still in the glass. It is spread through more water, so each sip carries less of it.
Q7transfer

A cook adds a cup of water to a pot of salty broth and stirs. How does each spoonful taste now?

  1. A more salty
  2. B less salty
  3. C just as salty
Answer

Key: B — less salty

The cook added solvent, not solute.
The same salt is spread through more broth.
Each spoonful carries less salt, so the broth is less salty: diluted.

Feedback per option

  • A Adding water adds no salt, so the broth cannot get saltier.
  • B The same salt is spread through more broth: diluted.
  • C The salt is spread through more broth, so each spoonful carries less salt.
Q8transfer

A student wants her cup of tea to taste weaker without pouring any out. What should she add?

  1. A more hot water
  2. B a spoon of sugar
  3. C another tea bag
Answer

Key: A — more hot water

To make a solution weaker, add solvent.
More hot water spreads the same tea through more liquid.
The concentration goes down, so the tea tastes weaker.

Feedback per option

  • A More water spreads the same tea through more liquid: diluted, weaker.
  • B Sugar adds a solute; it does not spread the tea through more water.
  • C Another tea bag adds more tea, so the tea gets stronger.
Q9transfer

A student stirs a second spoon of lemonade mix into the same glass of water. What happens to the concentration?

  1. A It goes down.
  2. B It stays the same.
  3. C It goes up.
Answer

Key: C — It goes up.

The student added solute, not solvent.
More solute in the same solvent means more concentrated.
So the concentration goes up: this is not diluting.

Feedback per option

  • A Adding solute is the opposite of diluting: the concentration rises.
  • B The water is the same and the mix doubled, so the concentration changes.
  • C More solute in the same solvent means more concentrated.
Q10transfer

Honey is dissolved in a glass of water, and then the glass is filled up with more water. How much honey is in the glass now, compared with before?

  1. A twice as much
  2. B the same amount
  3. C half as much
Answer

Key: B — the same amount

Diluting adds solvent only.
No honey was added, and no honey was taken away.
So the glass holds the same amount of honey, spread through more water.

Feedback per option

  • A Adding water adds no honey.
  • B Adding water adds no honey and takes none away.
  • C Adding water takes no honey away. The honey is spread thinner, but it is all there.
Your note · lesson 4: Adding water: diluting a solution
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 5 of 9Author: definitely a video198 words · about 1:39

Mass adds up when a solution forms

MAT-037 · Mass is conserved when a solution forms — Calculate the total mass of a solution from the masses of solute and solvent before mixing.

Script
SayScreen
A student puts an empty beaker on a balance and sets the reading to zero, then pours in water until it reads two hundred grams.[an empty beaker on a balance: readout 0 g; water pours in; readout 200 g]
She measures fifteen grams of salt onto a paper.[a paper with a heap on a second balance; 15 g]
She tips the salt in and stirs until every grain has vanished.[the heap slides in; the spoon stirs; the grains disappear]
She puts the beaker back on the balance. What does the salt water read?[the beaker returns; readout blank; question mark]
It reads two hundred fifteen grams, and here is why.[readout 215 g]
Zoomed in, the salt particles are spread out among the water particles.[sample box: open salt particles spread among filled water particles]
Every salt particle is still in the beaker, so its mass is still there.[the box outline; nothing crosses it]
The mass of a solution equals the mass of the solvent plus the mass of the solute.[equation: mass of solution = mass of solvent + mass of solute]
Two hundred grams plus fifteen grams equals two hundred fifteen grams.[worked form fills line by line; readout 215 g]
Write the values, the equation, the substitution, the calculation, and the answer with its unit.[the five line labels appear in turn]
Twelve grams of baking soda in two hundred fifty grams of water makes two hundred sixty-two grams.[worked form for the baking soda; 262 g]
Milliliters measure volume, not mass, so three hundred milliliters of water cannot go into the sum; only grams are added.[300 mL crossed out of a sum]
So, the mass of a solution equals the mass of the solvent plus the mass of the solute.[the rule slide: the equation card mass of solution = mass of solvent + mass of solute above the three balances; nothing else printed]
Okay, now your turn.[the rule slide's images hold; closing screen: one line — “The mass of a solution equals the mass of the solvent plus the mass of the solute.”]

“Okay, now your turn.” — the attached question

video

On a zeroed balance, water reads 200 g and salt reads 15 g. After the salt dissolves, what does the salt water read?

  1. A 200 g
  2. B 215 g
  3. C 185 g
Answer

Key: B — 215 g

Every salt particle is still in the beaker.
The mass of a solution equals the mass of the solvent plus the mass of the solute.
200 g + 15 g = 215 g.

Feedback per option

  • A The salt vanishes from sight, not from the balance: its 15 g are still in the beaker.
  • B Every salt particle is still in the water, so the two masses add.
  • C Nothing leaves the beaker, so no mass is lost.

Quiz after the video — the mastery check, 11 items

Q1recall

A sealed bottle of frozen juice is left on a table, and the juice thaws inside the sealed bottle. What happens to the mass of the bottle?

  1. A It goes down.
  2. B It goes up.
  3. C It stays the same.
Answer

Key: C — It stays the same.

The bottle is sealed, so no particle left and none arrived.
The same particles are all still there.
So the mass stays the same.

Feedback per option

  • A No particle left the sealed bottle, so no mass left.
  • B No particle entered the sealed bottle, so no mass arrived.
  • C The same particles are all still inside the sealed bottle.
Q2recall

A spoon of honey has dissolved in a mug of tea. Where is the honey now?

  1. A spread through the tea as tiny particles
  2. B gone from the mug for good
  3. C floating in a sweet layer on top of the tea
Answer

Key: A — spread through the tea as tiny particles

Dissolving breaks the honey into particles too small to see.
Those particles spread evenly through the tea.
So the honey is still in the mug, spread through the tea.

Feedback per option

  • A Dissolving spreads the honey particles evenly through the tea.
  • B The honey is not gone: every sip is sweet.
  • C Dissolved honey is spread evenly through the tea, not in a layer.
Q3scaffold

35 g of bath salt is stirred into 500 g of water until it vanishes. Which equation finds the mass of the salt water?

500 gthe water35 gthe bath salt
  1. A mass of solution = mass of solvent + mass of solute
  2. B mass of solution = mass of solvent − mass of solute
  3. C mass of solution = mass of solvent
Answer

Key: A — mass of solution = mass of solvent + mass of solute

Every bath salt particle is still in the water.
So the mass of the salt is added to the mass of the water.
Mass of solution = mass of solvent + mass of solute.

Feedback per option

  • A Every solute particle is still there, so the two masses add.
  • B Nothing left the water, so no mass is taken away.
  • C The bath salt is still in the water, so its mass counts too.
Q4scaffold

35 g of bath salt is stirred into 500 g of water. Which line substitutes the values correctly?

  1. A mass of solution = 500 g − 35 g
  2. B mass of solution = 500 g × 35 g
  3. C mass of solution = 500 g + 35 g
Answer

Key: C — mass of solution = 500 g + 35 g

The equation is mass of solution = mass of solvent + mass of solute.
Put the water, 500 g, in place of the solvent and the bath salt, 35 g, in place of the solute.
So mass of solution = 500 g + 35 g.

Feedback per option

  • A Nothing is taken away when the salt dissolves, so the masses add.
  • B The equation adds; it does not multiply.
  • C Mass of solvent + mass of solute: 500 g + 35 g.
Q5scaffold

35 g of bath salt is stirred into 500 g of water. Calculate the mass of the salt water, in g.

Typed answer

Answer

Accepted: 535 g · 535 · 535 grams

Values: mass of water = 500 g, mass of bath salt = 35 g.
Equation: mass of solution = mass of solvent + mass of solute.
Substitute: 500 g + 35 g.
Calculate: 500 + 35 = 535.
Answer: mass of solution = 535 g.
Q6scaffold

The water's mass and the bath salt's mass were both in grams. Which unit does the mass of the salt water carry?

  1. A mL
  2. B g
  3. C °C
Answer

Key: B — g

The water's mass was in g and the bath salt's mass was in g.
Grams added to grams come out in grams.
So the mass of the salt water is in g.

Feedback per option

  • A Milliliters measure a volume, not a mass.
  • B Both masses were in grams, so the sum is in grams.
  • C Degrees Celsius measure a temperature, not a mass.
Q7bare

18 g of instant coffee dissolves in 300 g of hot water. What is the mass of the coffee drink, in g?

Typed answer

Answer

Accepted: 318 g · 318 · 318 grams

Values: mass of water = 300 g, mass of instant coffee = 18 g.
Equation: mass of solution = mass of solvent + mass of solute.
Substitute: 300 g + 18 g.
Calculate: 300 + 18 = 318.
Answer: mass of solution = 318 g.
Q8bare

9 g of powdered plant food dissolves in 991 g of water. What is the mass of the plant-food water, in g?

Typed answer

Answer

Accepted: 1,000 g · 1000 g · 1000 · 1,000 · 1000 grams · 1,000 grams

Values: mass of water = 991 g, mass of plant food = 9 g.
Equation: mass of solution = mass of solvent + mass of solute.
Substitute: 991 g + 9 g.
Calculate: 991 + 9 = 1,000.
Answer: mass of solution = 1,000 g.
Q9bare

6 g of instant tea is stirred into 240 g of hot water at 75 °C until it vanishes. What is the mass of the tea drink, in g?

Typed answer

Answer

Accepted: 246 g · 246 · 246 grams

The temperature, 75 °C, is not a mass, so it is left out.
Values: mass of water = 240 g, mass of instant tea = 6 g.
Equation: mass of solution = mass of solvent + mass of solute.
Substitute: 240 g + 6 g.
Calculate: 240 + 6 = 246.
Answer: mass of solution = 246 g.
Q10scaffold

A student stirs 10 g of salt into 300 mL of water. Why can she not add 10 and 300 to find the mass of the salt water?

  1. A Salt loses its mass when it dissolves.
  2. B 300 mL is a volume, not a mass.
  3. C The two numbers must be multiplied together instead.
Answer

Key: B — 300 mL is a volume, not a mass.

The equation adds two masses in grams.
300 mL is a volume, not a mass.
She needs the mass of the water in grams before she can add.

Feedback per option

  • A The salt keeps all its mass; every salt particle is still there.
  • B She needs the mass of the water in grams before she can add.
  • C Masses are added, never multiplied, but both values must be masses first.
Q11misconception

Tessa stirs 25 g of sugar into 175 g of water until it vanishes. She says: "The sugar is still in the water, so the sugar water has a mass of 200 g." Is Tessa correct?

  1. A yes
  2. B no
Answer

Key: A — yes

Every sugar particle is still in the water, spread among the water particles.
Mass of solution = mass of solvent + mass of solute.
175 g + 25 g = 200 g, so Tessa is correct.

Feedback per option

  • A Every sugar particle is still in the water, so 175 g + 25 g = 200 g.
  • B Dissolving hides the sugar; it does not remove it. Every sugar particle is still in the water, so 175 g + 25 g = 200 g.
Your note · lesson 5: Mass adds up when a solution forms
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 6 of 9Author: definitely a video195 words · about 1:38

Dissolving faster: warmer water

MAT-038 · Temperature affects how fast a solute dissolves — Predict which of two otherwise identical solutions dissolves faster when the temperature is higher.

Script
SayScreen
Two cups each hold two hundred milliliters of water and one sugar cube.[two cups; a cube drops into each]
One cup is at twenty degrees Celsius, the other at sixty degrees Celsius, and nobody stirs.[labels 20 °C and 60 °C; no spoon]
The hot cup's cube is gone in three minutes; the cold cup's cube takes twelve minutes.[two timers; the hot cube shrinks fast, the cold cube slowly]
Why does the hot water dissolve the cube faster?[question mark]
Its particles move faster, and only the temperature differs between the cups.[the two-cup table; the temperature row highlighted]
Heating makes particles move faster.[chip: HEATING MAKES PARTICLES MOVE FASTER]
Zoomed in on the cube, water particles bump into its surface all the time.[box: a cube on the floor; water particles with arrows]
Each bump can knock a sugar particle off, and that particle spreads out among the water.[one open particle leaves the cube and drifts away]
In the hot cup, the water particles move faster, so they hit the cube harder and more often.[hot box: long arrows; many hits]
So the hot water knocks sugar particles off sooner, and the cube is gone in three minutes.[the hot cube shrinks away; 3 minutes]
In the cold cup, slow water particles knock sugar off slowly, so the cube lasts twelve minutes.[cold box: short arrows; the cube barely shrinks; 12 minutes]
Salt dissolves faster in warm water than in cold.[two bowls, the warm one clears first]
Here's the pattern. The warmer the solvent, the faster the solute dissolves.[the rule slide: the hot box and the cold box with their arrows; chip WARMER: FASTER; nothing else printed]
So the hot cup's water hit its cube harder and more often, and that cube dissolved first.[the two cups; 3 minutes against 12 minutes]
Okay, now your turn.[the rule slide's images hold; closing screen: one line — “The warmer the solvent, the faster the solute dissolves.”]

“Okay, now your turn.” — the attached question

video

A sugar cube in a cup of hot water dissolves before an identical cube in a cup of cold water. Why?

  1. A The heat melts the sugar cube, so the sugar runs out into the water.
  2. B Hot water has bigger gaps between its particles for the sugar to fall into.
  3. C The hot water's particles hit the cube harder and more often.
Answer

Key: C — The hot water's particles hit the cube harder and more often.

Heating makes the water particles move faster.
Faster water particles hit the cube harder and more often.
So they knock sugar particles off sooner, and the hot cup's cube dissolves first.

Feedback per option

  • A Sugar does not melt in hot water; it dissolves. The water's faster particles knock sugar particles off.
  • B Dissolving is done by water particles hitting the cube, not by gaps between them.
  • C Heating makes the water particles move faster, so their hits are harder and more frequent.

Quiz after the video — the mastery check, 10 items

Q1recall

A pan of water is heated on a stove. What happens to the water particles?

  1. A They move more slowly.
  2. B They move faster.
  3. C They stop moving.
Answer

Key: B — They move faster.

Heating makes particles move faster.
The water is heated.
So the water particles move faster.

Feedback per option

  • A Cooling makes particles move more slowly; heating does the opposite.
  • B Heating makes particles move faster.
  • C Particles in a liquid never stop moving; heating makes them move faster.
Q2what

In which bowl does the salt dissolve faster?

bowl Abowl Btemperature45 °C15 °Csaltsame amountsame amountstirringnonenone
  1. A bowl A
  2. B bowl B
Answer

Key: A — bowl A

The same salt, no stirring: only the temperature differs.
Bowl A is warmer, so its water particles move faster and hit the salt harder and more often.
So the salt dissolves faster in bowl A.

Feedback per option

  • A Bowl A is warmer, at 45 °C, so its water particles move faster.
  • B Bowl B is the cooler bowl, at 15 °C, so its water particles move more slowly.
Q3why

Bowl A holds water at 45 °C and bowl B holds water at 15 °C. The same salt goes into each, unstirred, and bowl A's salt is gone first. Explain why.

Starter: The salt dissolves faster in the warmer water because…

Answer

Model answer · ['heating makes the water particles move faster', 'faster water particles hit the salt harder and more often', 'so they knock salt particles off sooner, and the salt dissolves faster'] points

The salt dissolves faster in the warmer water because heating makes the water particles move faster.
Faster water particles hit the salt harder and more often.
So they knock salt particles off sooner.
So the salt dissolves faster in the warmer water.
Q4why

Why does a solute dissolve faster in warmer water?

  1. A The water particles move faster, so they hit the solute harder and more often.
  2. B Warm water has bigger gaps between its particles, so the solute falls into them.
  3. C Warm water has fewer particles in it, so less water touches the solute.
Answer

Key: A — The water particles move faster, so they hit the solute harder and more often.

Heating makes the water particles move faster.
Faster water particles hit the solute harder and more often.
So they knock solute particles off sooner, and the solute dissolves faster.

Feedback per option

  • A Harder and more frequent hits knock solute particles off sooner.
  • B Dissolving is done by water particles hitting the solute, not by gaps.
  • C Warming does not remove water particles; it speeds them up.
Q5misconception

Luis says: "Hot water dissolves sugar faster because the heat melts the sugar." Is Luis correct?

  1. A yes
  2. B no
Answer

Key: B — no

The sugar does not melt in the cup; it dissolves.
Heating makes the water particles move faster.
Faster water particles hit the sugar harder and more often, so they knock sugar particles off sooner, and Luis is not correct.

Feedback per option

  • A The sugar does not melt; it dissolves. The hot water's particles hit the sugar harder and more often, so they knock sugar particles off sooner.
  • B Hot water's particles move faster, so they hit the sugar harder and more often and knock sugar particles off sooner.
Q6transfer

In which glass does the drink powder dissolve faster?

the iced glassthe hot glasstemperature5 °C70 °Cdrink powdersame amountsame amountstirringnonenone
  1. A the iced glass
  2. B the hot glass
Answer

Key: B — the hot glass

The same powder, no stirring: only the temperature differs.
The hot glass's water particles move faster and hit the powder harder and more often.
So the powder dissolves faster in the hot glass.

Feedback per option

  • A The iced glass is at 5 °C, so its water particles move slowly.
  • B The hot glass is at 70 °C, so its water particles move fast and hit the powder harder and more often.
Q7transfer

In which cup does the salt dissolve faster?

cup Acup Btemperature25 °C25 °Csaltsame amountsame amountstirringnonenone
  1. A cup A
  2. B cup B
  3. C neither cup
Answer

Key: C — neither cup

Both cups are at 25 °C.
Their water particles move at the same speed, so they hit the salt equally hard and equally often.
So the salt takes the same time in each cup.

Feedback per option

  • A Cup A has no head start. Both cups are at 25 °C, so their water particles move at the same speed.
  • B Cup B has no head start. Both cups are at 25 °C, so their water particles move at the same speed.
  • C Nothing differs between the cups, so the salt dissolves at the same rate in each.
Q8transfer

A student wants a hard candy to last as long as possible in a glass of water. Which water should she use?

  1. A cooler water
  2. B warmer water
Answer

Key: A — cooler water

The warmer the solvent, the faster the solute dissolves.
Cooler water's particles move more slowly and hit the candy less hard and less often.
So the candy lasts longer in cooler water.

Feedback per option

  • A Cooler water's particles move more slowly, so they knock candy particles off more slowly.
  • B Warmer water dissolves the candy faster, so it would last less time.
Q9transfer

A lump of rock salt needs 10 minutes to dissolve in cool water. The same kind of lump is dropped into hot water and not stirred. How long does it need?

  1. A less than 10 minutes
  2. B 10 minutes
  3. C more than 10 minutes
Answer

Key: A — less than 10 minutes

The warmer the solvent, the faster the solute dissolves.
The hot water's particles hit the lump harder and more often.
So the lump dissolves in less than 10 minutes.

Feedback per option

  • A Hot water's particles hit the lump harder and more often, so the lump goes sooner.
  • B The temperature changed, so the time changes too.
  • C Hot water speeds dissolving up; it does not slow it down.
Q10fluency

Compared with cold water, how do the particles of hot water hit a lump of salt?

  1. A more gently and less often
  2. B in the same way
  3. C harder and more often
Answer

Key: C — harder and more often

Heating makes the water particles move faster.
Faster particles hit harder and arrive more often.
So hot water's particles hit the lump harder and more often.

Feedback per option

  • A Slower, gentler hits belong to cold water.
  • B Hot water particles move faster than cold water particles, so the hits differ.
  • C Heating makes the water particles move faster, so each hit is harder and hits come more often.
Your note · lesson 6: Dissolving faster: warmer water
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 7 of 9Author: definitely a video189 words · about 1:34

Dissolving faster: smaller pieces

MAT-039 · Surface area affects how fast a solute dissolves — Predict which of two equal-mass solute samples dissolves faster based on their particle size.

Script
SayScreen
Two cups each hold two hundred milliliters of water at twenty degrees Celsius.[two cups; label 20 °C]
One gets a four-gram cube, the other four grams of loose grains, and nobody stirs.[a cube drops into one; grains pour into the other]
The grains are gone in two minutes; the cube takes twelve minutes.[two timers; the grains vanish; the cube barely shrinks]
The sugar, the water and the temperature are the same, so why do the grains dissolve first?[the two-cup table; the sugar row highlighted; question mark]
The grains have far more surface for the water to reach.[chip: MORE SURFACE]
Water particles bump into the sugar's surface, and each bump can knock a sugar particle off.[box: water particles hitting a cube; one open particle leaves]
A particle deep inside the cube cannot be reached until the sugar around it has gone.[the cube's inside shaded; arrows stop at the surface]
So dissolving happens only at the surface.[chip: ONLY AT THE SURFACE]
The cube has six faces for the water to reach.[the cube; its six faces flash]
Cut into eight small cubes, it has forty-eight faces: twice the surface, all reached by water.[the cube splits into eight; 48 faces flash; label: twice the surface]
More surface means more water particles hitting sugar at once, so more sugar comes off at once.[many arrows hit many grains; open particles leave from all sides]
Fine salt dissolves faster than coarse salt.[two bowls, the fine salt clears first]
Both cups hold the same four grams: breaking changes the surface, not the mass.[4 g under the cube; 4 g under the grains]
Here's the pattern. The smaller the pieces of a solute, the faster it dissolves.[the rule slide: the cube and the eight small cubes; chip SMALLER PIECES: FASTER; nothing else printed]
Okay, now your turn.[the rule slide's images hold; closing screen: one line — “The smaller the pieces of a solute, the faster it dissolves.”]

“Okay, now your turn.” — the attached question

video

Four grams of loose sugar grains dissolve before a four-gram sugar cube in the same water. Why?

  1. A The grains have less sugar in them than the one cube has.
  2. B The grains have far more surface for the water to reach.
  3. C The grains are in warmer water than the cube is.
Answer

Key: B — The grains have far more surface for the water to reach.

Dissolving happens only at the surface of the sugar.
The loose grains have far more surface than the one cube.
So more sugar particles are knocked off at once, and the grains are gone first.

Feedback per option

  • A Both cups get 4 g. The mass is the same.
  • B Dissolving happens only at the surface, and the grains have far more of it.
  • C Both cups are at 20 °C. The temperature is the same.

Quiz after the video — the mastery check, 10 items

Q1recall

Water particles bump into a lump of salt. What can each bump do?

  1. A knock a salt particle off the lump
  2. B push the lump to the bottom
  3. C make the water around the lump colder
Answer

Key: A — knock a salt particle off the lump

Water particles bump into the surface of the salt all the time.
Each bump can knock a salt particle off the lump.
That salt particle then spreads out among the water: it has dissolved.

Feedback per option

  • A A knocked-off salt particle spreads out among the water particles: it has dissolved.
  • B The bumps work on the salt particles, not on where the lump sits.
  • C The bumps do not cool the water; they knock salt particles off.
Q2what

One bath bomb is dropped into a tub whole. Another, the same size, is crumbled first and dropped in. Which dissolves faster?

  1. A the crumbled one
  2. B the whole one
Answer

Key: A — the crumbled one

Dissolving happens only at the surface.
The crumbs have far more surface than the whole bath bomb.
More particles are knocked off at once, so the crumbled one dissolves faster.

Feedback per option

  • A The crumbs have far more surface for the water to reach.
  • B The whole bath bomb offers less surface, so fewer particles are knocked off at once.
Q3why

One bath bomb goes into a tub whole, and another of the same size is crumbled first. The crumbled one is gone first. Explain why.

Starter: The crumbled bath bomb dissolves faster because…

Answer

Model answer · ['water particles knock particles off the surface only', 'the crumbs have far more surface than the whole bath bomb', 'so more particles are knocked off at once, and it dissolves faster'] points

The crumbled bath bomb dissolves faster because water particles knock particles off the surface only.
The crumbs have far more surface than the whole bath bomb.
So more water particles hit the bath bomb at the same moment.
So more particles are knocked off at once, and the crumbled bath bomb dissolves faster.
Q4why

Why does a crushed tablet dissolve faster than a whole tablet?

  1. A Crushing makes the water around the tablet warmer.
  2. B The crushed pieces have more surface for the water to reach.
  3. C The crushed pieces have less mass for the water to dissolve away.
Answer

Key: B — The crushed pieces have more surface for the water to reach.

Dissolving happens only at the surface.
The crushed pieces have far more surface than the whole tablet.
So more particles are knocked off at once, and the crushed tablet dissolves faster.

Feedback per option

  • A Crushing changes the tablet, not the water's temperature.
  • B More surface means more water particles hitting the tablet at once.
  • C The pieces hold the same mass as the whole tablet. Only the surface changes.
Q5misconception

Dante drops 5 g of sugar grains into one glass of water and a 5 g sugar cube into another. The grains dissolve first. He says: "The grains dissolved faster because there was less sugar." Is Dante correct?

  1. A yes
  2. B no
Answer

Key: B — no

Both glasses got the same 5 g of sugar, so there was not less sugar.
The loose grains have far more surface for the water to reach.
More surface, not less mass, is the reason, so Dante is not correct.

Feedback per option

  • A Both glasses got 5 g, so there was not less sugar. The grains dissolved faster because they have far more surface.
  • B Both glasses got 5 g of sugar. The grains dissolved faster because they have far more surface for the water to reach.
Q6transfer

Coarse salt with big crystals and fine salt with tiny crystals, the same mass of each, are dropped into two bowls of water that are equally warm. Which dissolves faster?

  1. A the coarse salt
  2. B the fine salt
Answer

Key: B — the fine salt

Dissolving happens only at the surface.
The fine salt's tiny crystals have far more surface than the coarse salt's big crystals.
So the fine salt dissolves faster.

Feedback per option

  • A Big crystals offer less surface, so fewer salt particles are knocked off at once.
  • B Tiny crystals have far more surface, so more salt particles are knocked off at once.
Q7transfer

A student wants a piece of hard candy to dissolve as slowly as possible in her water. What should she do with it?

  1. A crush it first
  2. B drop it in whole
  3. C grate it into powder
Answer

Key: B — drop it in whole

The smaller the pieces, the faster a solute dissolves.
One whole piece has the least surface for the water to reach.
So the whole piece dissolves slowest.

Feedback per option

  • A Crushing adds surface, so the candy would dissolve faster.
  • B One whole piece offers the least surface, so it dissolves slowest.
  • C Powder has the most surface of all, so it would dissolve fastest.
Q8fluency

Where do water particles knock solute particles off a lump?

  1. A from the whole lump at the same time
  2. B only from deep inside the lump
  3. C only at the surface of the lump
Answer

Key: C — only at the surface of the lump

Water particles can only bump into the surface of the lump.
A particle deep inside cannot be reached until the solute around it has gone.
So the knocking happens only at the surface.

Feedback per option

  • A Water cannot reach the inside of the lump until the outside has gone.
  • B The inside is not reached until the surface around it has gone.
  • C Water particles can only hit the surface, so that is where the knocking happens.
Q9fluency

A 6 g lump of rock candy is broken into small pieces. What is the total mass of the pieces?

  1. A less than 6 g
  2. B 6 g
  3. C more than 6 g
Answer

Key: B — 6 g

Breaking a solute into pieces changes its surface, not its mass.
Every piece of the lump is still there.
So the pieces have a total mass of 6 g.

Feedback per option

  • A Breaking moves no candy away. Every piece is still there.
  • B Breaking changes the surface, not the mass: the pieces still hold 6 g.
  • C Breaking adds no candy.
Q10fluency

A powder and a single lump have the same mass. Which has more surface for the water to reach?

  1. A the powder
  2. B the lump
  3. C They have the same surface.
Answer

Key: A — the powder

Cut a solid into smaller pieces, and every piece gains faces of its own.
The powder is the same mass in many tiny pieces.
So the powder has far more surface than the lump.

Feedback per option

  • A Every tiny grain of the powder has faces of its own for the water to reach.
  • B One lump has the least surface for its mass.
  • C The same mass in many small pieces has far more surface than in one lump.
Your note · lesson 7: Dissolving faster: smaller pieces
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 8 of 9Author: definitely a video200 words · about 1:40

Dissolving faster: stirring

MAT-040 · Agitation affects how fast a solute dissolves — Predict which of two otherwise identical solutions dissolves faster when one is stirred.

Script
SayScreen
Two cups each hold two hundred milliliters of water at twenty degrees Celsius and one sugar cube.[two cups; a cube in each; label 20 °C]
A student stirs one cup and leaves the other still.[a spoon circles in one cup]
The stirred cube is gone in two minutes; the still one takes twelve minutes.[two timers; the stirred cube vanishes]
Why does stirring help?[question mark]
Stirring keeps bringing fresh water to the cube.[chip: FRESH WATER]
Only the stirring differs, so stirring is the reason.[the two-cup table; the stirring row highlighted]
Water particles knock sugar particles off the cube into the water next to it.[box: a cube; open particles leave its surface]
In the still cup, that water soon holds many sugar particles.[a shaded dome of open particles around the cube]
That crowded water has little room for new sugar, so fewer sugar particles come off, and the cube lasts twelve minutes.[few new particles leave; 12 minutes]
In the stirred cup, the spoon sweeps that crowded water away, and fresh water arrives.[the spoon; curved sweep arrows; the crowded water is carried off]
Fresh water knocks off new sugar quickly, so the cube is gone in two minutes.[many particles leave; 2 minutes]
Shaking a bottle of salt and water does the same job, so the salt dissolves faster.[two bottles; the shaken one clears first]
Warmer water, smaller pieces and stirring each make a solute dissolve faster.[the three-row table of speed-ups]
None of the three changes how much solute there is, only how fast it dissolves.[chip: FASTER, NOT MORE]
So, stirring makes a solute dissolve faster, because it brings fresh water to the solute.[the rule slide: the stirred box with its sweep arrows; chip STIRRING: FASTER; nothing else printed]
Okay, now your turn.[the rule slide's images hold; closing screen: bullets — • Warmer water makes a solute dissolve faster. • Smaller pieces make a solute dissolve faster. • Stirring makes a solute dissolve faster, because it brings fresh water to the solute.]

“Okay, now your turn.” — the attached question

video

A stirred sugar cube dissolves before a still one in the same water. What does the stirring keep bringing to the cube?

  1. A fresh water
  2. B warmer water
  3. C more sugar
Answer

Key: A — fresh water

Around a still cube, the nearby water soon holds many sugar particles.
Stirring sweeps that water away and brings fresh water to the cube.
Fresh water knocks off more sugar particles, so the stirred cube dissolves first.

Feedback per option

  • A The spoon sweeps the water crowded with sugar particles away and brings fresh water, which knocks off more sugar particles.
  • B Stirring does not warm the water.
  • C Stirring adds no sugar; it changes how fast the cube dissolves.

Quiz after the video — the mastery check, 10 items

Q1recall

Water particles knock solute particles off a lump. Where do the knocked-off particles go?

  1. A into the water next to the lump
  2. B back into the lump
  3. C out of the water as a gas
Answer

Key: A — into the water next to the lump

Each bump knocks a solute particle off the surface.
The knocked-off particle spreads out into the water next to the lump.
That is how the solute dissolves.

Feedback per option

  • A They spread out into the water next to the lump, and then farther.
  • B A knocked-off particle has left the lump; it spreads into the water.
  • C The particles stay in the water; that is dissolving.
Q2what

Two identical bottles hold water and the same amount of salt. One bottle is shaken, and one is left still. In which bottle does the salt dissolve faster?

  1. A the still bottle
  2. B the shaken bottle
Answer

Key: B — the shaken bottle

Only the shaking differs between the bottles.
Shaking sweeps the salty water away from the salt and brings fresh water to it.
Fresh water knocks off more salt particles, so the shaken salt dissolves faster.

Feedback per option

  • A In the still bottle the salty water stays around the salt, so fewer new salt particles come off.
  • B Shaking sweeps the salty water away and brings fresh water to the salt.
Q3why

Two identical bottles hold water and the same salt; one is shaken and one is left still. The shaken bottle's salt is gone first. Explain why.

Starter: The salt dissolves faster in the shaken bottle because…

Answer

Model answer · ['shaking sweeps the salty water away from the salt', 'fresh water arrives at the salt', 'fresh water knocks off more salt particles, so the salt dissolves faster'] points

The salt dissolves faster in the shaken bottle because shaking sweeps the salty water away from the salt.
Fresh water, with no salt in it yet, arrives at the salt.
Fresh water knocks off more salt particles.
So the salt dissolves faster in the shaken bottle.
Q4why

Why does stirring make a solute dissolve faster?

  1. A Stirring heats the water around the solute.
  2. B Stirring breaks the water particles into smaller pieces.
  3. C Stirring brings fresh water to the solute.
Answer

Key: C — Stirring brings fresh water to the solute.

Around a still solute, the nearby water soon holds many solute particles.
Stirring sweeps that crowded water away and brings fresh water to the solute.
Fresh water knocks off more solute particles, so the solute dissolves faster.

Feedback per option

  • A Stirring does not warm the water. It moves the water.
  • B Water particles do not break. Stirring moves them.
  • C Stirring sweeps the crowded water away, and fresh water knocks off more solute particles than crowded water does.
Q5misconception

Yara drops the same kind of sugar cube into two cups of water and stirs only one. She says: "Stirring dissolves more sugar in total, so the stirred cup ends up sweeter." Is Yara correct?

  1. A yes
  2. B no
Answer

Key: B — no

Each cup got the same cube, so each holds the same sugar once the cube has dissolved.
Stirring changes only how fast the sugar dissolves.
It does not change how much sugar there is, so Yara is not correct.

Feedback per option

  • A Stirring changes how fast the cube dissolves, not how much sugar there is. Both cups got one cube, so both end up equally sweet.
  • B Both cups got one cube, so both end up with the same sugar. Stirring changes only how fast the cube dissolves.
Q6transfer

A student stirs drink powder in one glass and lets the same powder sit in another glass, equally warm. Which powder dissolves faster?

  1. A the stirred powder
  2. B the powder left to sit
Answer

Key: A — the stirred powder

Only the stirring differs between the glasses.
Stirring sweeps the powder-rich water away and brings fresh water to the powder.
So the stirred powder dissolves faster.

Feedback per option

  • A Stirring keeps bringing fresh water to the powder.
  • B Around the still powder, the nearby water soon holds many powder particles, so fewer new ones come off.
Q7transfer

A student wants a spoon of salt to dissolve as fast as possible. Which set-up is fastest?

  1. A cold water, fine salt, left still
  2. B warm water, coarse salt, left still
  3. C warm water, fine salt, stirred
Answer

Key: C — warm water, fine salt, stirred

Warmer water, smaller pieces and stirring each make a solute dissolve faster.
Warm water, fine salt and stirring use all three.
So that set-up dissolves the salt fastest.

Feedback per option

  • A Fine salt helps, but cold still water is slow on the other two counts.
  • B Warm water helps, but coarse salt and no stirring are slow on the other two counts.
  • C Warmer water, smaller pieces and stirring each speed dissolving, and this set-up has all three.
Q8transfer

Which of these does NOT make a lump of salt dissolve faster?

  1. A using warmer water
  2. B using a glass cup
  3. C crushing the lump first
  4. D stirring the water
Answer

Key: B — using a glass cup

Warmer water, smaller pieces and stirring each make a solute dissolve faster.
The material of the cup changes neither the water nor the lump.
So a glass cup instead of a plastic cup makes no difference.

Feedback per option

  • A Warmer water's particles hit the lump harder and more often.
  • B The cup's material changes nothing about the water or the lump.
  • C Crushing gives the salt far more surface for the water to reach.
  • D Stirring brings fresh water to the lump.
Q9fluency

Two glasses each got one salt tablet, and both tablets have fully dissolved. Only one glass was stirred. Which glass holds more salt?

  1. A the stirred glass
  2. B both the same
  3. C the still glass
Answer

Key: B — both the same

Each glass got one tablet of the same salt.
Stirring changes only how fast the tablet dissolves.
So both glasses hold the same salt.

Feedback per option

  • A Stirring changed the speed, not the amount: one tablet each.
  • B Each glass got one tablet, so each holds the same salt.
  • C The still glass got the same one tablet.
Q10fluency

In a still cup, what happens to the water right next to a lump of salt?

  1. A It stays free of salt.
  2. B It gets warmer than the rest.
  3. C It soon holds many salt particles.
Answer

Key: C — It soon holds many salt particles.

Water particles knock salt particles off the lump.
In a still cup those salt particles stay close to the lump.
So the water next to the lump soon holds many salt particles.

Feedback per option

  • A Knocked-off salt particles spread into that water first.
  • B Dissolving does not warm the water next to the lump.
  • C The knocked-off salt particles stay close to the lump, so that water grows crowded with them.
Your note · lesson 8: Dissolving faster: stirring
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Lesson 9 of 9Author: definitely a video200 words · about 1:40

Choose a way to separate a mixture

MAT-041 · Choose a separation technique — Select an appropriate separation method for a mixture by matching it to the property difference between its components.

Script
SayScreen
Four mixtures sit on a bench: coffee grounds in water, salt dissolved in water, nails in wood shavings, marbles in sand.[four containers in a row, labeled]
A student must get one part out of each, and no single method works for all four.[a question mark over each]
How does she pick?[question mark]
She names the two parts, then finds a property that one part has and the other does not.[chip: FIND THE PROPERTY THAT DIFFERS]
Coffee grounds do not dissolve, and they are too big for a paper cone's tiny holes.[a paper cone in a funnel; the mixture pours in]
Poured through the paper, the water runs through and the grounds stay, and this is called filtering.[clear water drips into the beaker; grounds on the paper; chip: FILTERING]
Dissolved salt is too small for paper to hold, but water evaporates and salt does not.[salt water runs straight through a filter; then a pan]
Left in a warm pan, the water leaves as a gas and the salt stays, and this is called evaporating.[the pan of salt water; wavy lines rise; then the dry pan with salt grains left; chip: EVAPORATING]
A magnet pulls iron and not wood, so it lifts the nails out of the shavings, and this is called using a magnet.[a bar magnet; nails cling; shavings stay; chip: USING A MAGNET]
Marbles are big and sand grains small, so on a mesh the sand falls through, and this is called sieving.[a mesh over a bowl; sand falls; chip: SIEVING]
So, to separate a mixture, find a property that one part has and the other does not, and pick the method that uses it.[the rule slide: chips NAME THE PARTS, FIND THE PROPERTY THAT DIFFERS, PICK THE METHOD beside the four set-ups; nothing else printed]
Okay, now your turn.[the rule slide's images hold; closing screen: bullets — • Name the two parts. • Find a property that one part has and the other does not. • Pick the method that uses it.]

“Okay, now your turn.” — the attached question

video

Salt has dissolved in water, so filter paper cannot hold it back. Which method gets the salt out?

  1. A filtering
  2. B evaporating
  3. C sieving
Answer

Key: B — evaporating

The salt is dissolved, so no paper or mesh can hold its particles back.
Water evaporates when warmed, and salt does not.
So evaporating leaves the salt behind.

Feedback per option

  • A Dissolved salt particles are far too small for paper to hold back.
  • B The water leaves as a gas, and the salt stays on the pan.
  • C Dissolved salt has no pieces for a mesh to hold.

Quiz after the video — the mastery check, 14 items

Q1recall

Steel pins are mixed into a jar of dried beans. Steel is magnetic. In the mixture, are the pins still magnetic?

  1. A yes
  2. B no
Answer

Key: A — yes

In a mixture each substance keeps its own properties.
The pins are still steel.
So the pins are still magnetic.

Feedback per option

  • A In a mixture each substance keeps its own properties.
  • B Mixing changes nothing about the steel: it keeps its magnetism.
Q2recall

Salt has dissolved in a jar of water. What has happened to the salt?

  1. A It sank to the bottom of the jar as grains of salt.
  2. B It spread through the water as particles too small to see.
  3. C It floated to the top of the water in a layer.
Answer

Key: B — It spread through the water as particles too small to see.

Dissolving breaks the salt into particles too small to see.
Those particles spread evenly through the water.
So no grains of salt remain to be seen.

Feedback per option

  • A Dissolved salt does not sit as grains; its particles are spread through the water.
  • B That is what dissolving means: particles too small to see, spread evenly.
  • C Dissolved salt is spread evenly through the water, not in a layer.
Q3scaffold

Steel bolts are mixed with wooden beads of the same size in a box. Steel is magnetic; wood is not. Which part is magnetic?

  1. A the bolts
  2. B the beads
Answer

Key: A — the bolts

Steel is magnetic, and wood is not.
The bolts are steel, so the bolts are magnetic.
The beads are wood, so the beads are not.

Feedback per option

  • A Steel is magnetic, and the bolts are steel.
  • B The beads are wood, and wood is not magnetic.
Q4scaffold

Steel bolts are mixed with wooden beads of the same size. Which property do the bolts have that the beads do not?

  1. A dissolving in water
  2. B being magnetic
  3. C being bigger than the beads
Answer

Key: B — being magnetic

Find a property that one part has and the other does not.
Steel is magnetic, and wood is not.
So being magnetic is the property the bolts have and the beads do not.

Feedback per option

  • A Neither steel nor wood dissolves in water, so that property does not differ.
  • B Steel is magnetic and wood is not: a property one part has and the other does not.
  • C The bolts and the beads are the same size, so size does not differ here. Steel is magnetic and wood is not.
Q5scaffold

Steel bolts are mixed with wooden beads of the same size. Which method separates the bolts from the beads?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: C — using a magnet

The property that differs is magnetism: steel is magnetic, wood is not.
Pick the method that uses that property.
A magnet lifts the bolts and leaves the beads.

Feedback per option

  • A Filtering separates undissolved pieces from a liquid; there is no liquid here.
  • B Evaporating separates a dissolved solute from its solvent; nothing is dissolved here.
  • C A magnet pulls the steel bolts and does not pull the wooden beads.
  • D The bolts and the beads are the same size, so a mesh holds both or drops both.
Q6fluency

Crushed eggshell, ground as fine as flour, is stirred into water and stays as bits. Which method gets the eggshell out?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: A — filtering

The two parts are eggshell bits and water.
The eggshell did not dissolve, and water pours through paper.
So the method is filtering.

Feedback per option

  • A The eggshell did not dissolve, so paper holds it back while the water runs through.
  • B Nothing is dissolved here; the eggshell bits can be held back by paper.
  • C Eggshell is not magnetic.
  • D A mesh is for big pieces among small ones. Here the other part is water: paper lets the water run through and holds the eggshell bits back.
Q7fluency

Salt is dissolved in a pan of sea water. Which method gets the salt out?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: B — evaporating

The two parts are dissolved salt and water.
Water evaporates when warmed; salt does not.
So the method is evaporating.

Feedback per option

  • A Dissolved salt particles are far too small for paper to hold back.
  • B The water evaporates and the salt does not, so the salt is left behind.
  • C Salt is not magnetic.
  • D Dissolved salt has no pieces for a mesh to hold.
Q8fluency

Steel screws are mixed with brass screws of the same size. Steel is magnetic; brass is not. Which method gets the steel screws out?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: C — using a magnet

The two parts are steel screws and brass screws.
A magnet pulls steel and does not pull brass.
So the method is using a magnet.

Feedback per option

  • A There is no liquid to pour through paper.
  • B Nothing is dissolved in a solvent.
  • C A magnet pulls the steel screws and does not pull the brass screws.
  • D The screws are the same size, so a mesh holds both or drops both.
Q9fluency

Plastic bottle caps are mixed into dry beach sand. Which method gets the caps out?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: D — sieving

The two parts are plastic bottle caps and sand.
Caps are big; sand grains are small.
So the method is sieving.

Feedback per option

  • A There is no liquid to pour through paper.
  • B Nothing is dissolved in a solvent.
  • C Plastic is not magnetic; the difference is size.
  • D Caps are big and sand grains are small, so the sand falls through a mesh and the caps stay.
Q10fluency

Baking soda is dissolved in a bowl of water. Which method gets the baking soda out?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: B — evaporating

The two parts are dissolved baking soda and water.
Water evaporates when warmed; baking soda does not.
So the method is evaporating.

Feedback per option

  • A Dissolved baking soda particles pass straight through paper.
  • B The water evaporates and the baking soda does not, so it is left behind.
  • C Baking soda is not magnetic.
  • D Dissolved baking soda has no pieces for a mesh to hold.
Q11fluency

Steel washers are mixed with plastic washers of the same size. Steel is magnetic. Which method gets the steel washers out?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: C — using a magnet

The two parts are steel washers and plastic washers.
A magnet pulls steel and does not pull plastic.
So the method is using a magnet.

Feedback per option

  • A There is no liquid to pour through paper.
  • B Nothing is dissolved in a solvent.
  • C A magnet pulls the steel washers and does not pull the plastic washers.
  • D The washers are the same size, so a mesh holds both or drops both.
Q12fluency

Dried peas are mixed into a bag of flour. Which method gets the peas out?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: D — sieving

The two parts are peas and flour.
Peas are big; flour grains are tiny.
So the method is sieving.

Feedback per option

  • A There is no liquid to pour through paper.
  • B Nothing is dissolved in a solvent.
  • C Neither peas nor flour is magnetic.
  • D Peas are big and flour grains are tiny, so the flour falls through a mesh and the peas stay.
Q13fluency

Cornmeal stirred into water clouds it and then settles as grains. Which method gets the cornmeal out?

  1. A filtering
  2. B evaporating
  3. C using a magnet
  4. D sieving
Answer

Key: A — filtering

The two parts are cornmeal grains and water.
The cornmeal did not dissolve, and water pours through paper.
So the method is filtering.

Feedback per option

  • A The cornmeal did not dissolve, so paper holds it back while the water runs through.
  • B Evaporating takes the water away and leaves everything behind, cornmeal included. Nothing is dissolved here, so filtering is the method.
  • C Cornmeal is not magnetic.
  • D The other part is water: paper lets the water run through and holds the cornmeal grains back, so filtering is the method.
Q14routine

A student must separate a mixture. After naming its two parts, what does she look for?

  1. A a property one part has and the other lacks
  2. B the part that there is more of in the mixture
  3. C the part that has the most mass in the mixture
Answer

Key: A — a property one part has and the other lacks

The routine is: name the two parts; find a property one part has and the other does not; pick the method that uses it.
So after naming the parts she looks for the property that differs.

Feedback per option

  • A That property is what the method will use.
  • B How much of each part there is does not pull the parts apart; a property that differs does.
  • C Mass alone does not pull parts apart; a property that differs does.
Your note · lesson 9: Choose a way to separate a mixture
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Summary video · everything taught, in order, just before the PP100269 words · about 2:14

Summary: Solutions and separating mixtures

Script, part 1 (122 words)
SayScreen
Here is everything we found out about solutions and separating mixtures.[a still: a glass of drink-mix solution and the sample box beside it]
A mixture in which one substance has dissolved evenly into another is called a solution.[chip: SOLUTION; sample box: open particles spread among filled ones]
The substance that dissolves is called the solute. The substance it dissolves into is called the solvent.[chips: SOLUTE, SOLVENT]
How much solute is dissolved in a given amount of solvent is called the concentration.[chip: CONCENTRATION]
More solute in the same solvent means more concentrated. The same solute in more solvent means less concentrated.[two boxes: more open particles in the same water; the same open particles in more water]
Adding more solvent to a solution is called diluting it, and the concentration goes down.[chip: DILUTING; the box stretches wider]
No solute is lost when a solution is diluted.[the same open particles counted in the wider box]
And the mass of a solution equals the mass of the solvent plus the mass of the solute.[equation card: mass of solution = mass of solvent + mass of solute]
Okay, now your turn.[the still holds]

“Okay, now your turn.” — the check question between the parts

video

Sugar dissolves into water to make sweet water. Which one is the solvent?

  1. A the sugar
  2. B the water
Answer

Key: B — the water

The substance that dissolves is called the solute.
The substance it dissolves into is called the solvent.
The sugar dissolves into the water, so the water is the solvent.

Feedback per option

  • A The sugar dissolves, so the sugar is the solute.
  • B The substance the solute dissolves into is called the solvent.
Script, part 2 (147 words)
SayScreen
Here is everything we found out about dissolving faster and taking a mixture apart.[a still: a sugar cube in a cup beside a funnel, a pan, a magnet and a mesh]
Warmer water, smaller pieces and stirring each make a solute dissolve faster.[the three-row table of speed-ups]
The warmer the solvent, the faster the solute dissolves, because faster water particles hit the solute harder and more often.[box: long arrows hitting a cube]
The smaller the pieces of a solute, the faster it dissolves, because dissolving happens only at the surface.[the cube beside the eight small cubes]
Stirring makes a solute dissolve faster, because it brings fresh water to the solute.[the spoon's sweep arrows]
Warmer water, smaller pieces and stirring change how fast a solute dissolves, not how much solute there is.[chip: FASTER, NOT MORE]
To separate a mixture, find a property that one part has and the other does not.[chip: FIND THE PROPERTY THAT DIFFERS]
Filtering separates undissolved pieces from a liquid, and evaporating separates a dissolved solute from its solvent.[the funnel; the pan; chips FILTERING, EVAPORATING]
A magnet lifts out a magnetic part, and sieving separates big pieces from small ones.[the magnet; the mesh; chips USING A MAGNET, SIEVING]
Okay, now your turn.[the still holds]

“Okay, now your turn.” — the two questions after part 2

video

A sugar cube is dropped into a cup of hot water and another into a cup of cold water, and nobody stirs. Which cube dissolves faster?

  1. A the cube in the hot water
  2. B the cube in the cold water
Answer

Key: A — the cube in the hot water

The warmer the solvent, the faster the solute dissolves.
So the cube in the hot water dissolves faster.

Feedback per option

  • A The warmer the solvent, the faster the solute dissolves.
  • B Cold water's particles move more slowly, so they knock sugar off more slowly.
video

Iron nails are mixed into a tray of wood shavings. Which method lifts the nails out?

  1. A filtering
  2. B using a magnet
  3. C evaporating
Answer

Key: B — using a magnet

To separate a mixture, find a property one part has and the other does not.
A magnet pulls iron; it does not pull wood.
So a magnet lifts the nails and leaves the shavings.

Feedback per option

  • A There is no liquid to pour through paper.
  • B A magnet pulls iron and does not pull wood, so the nails jump to the magnet.
  • C Nothing is dissolved in a solvent.
Your note · the summary video
What to judge

Is this content better than the current alternative students have (PhysicsGraph / Edmentum)?

8/10 on:

  • Clear and concise language
  • Physics accuracy (read as chemistry accuracy here; his line as pasted for HS Physics)
  • No "clangers" (content that causes a problematic misconception)
  • Appropriate questions
  • Initial testing
  • Expansion into harder questions (no exam)
  • The tasks should use similar language to that of the lesson

Gut check: better than the alternative? Would a student benefit? Full criteria

Applied without asking

Rulings you have already given; in force on every card above, not re-asked.

The topic’s fixed wording (the lexicon the scripts repeat)
  • A mixture in which one substance has dissolved evenly into another is called a solution.
  • The substance that dissolves is called the solute. The substance it dissolves into is called the solvent.
  • How much solute is dissolved in a given amount of solvent is called the concentration.
  • Adding more solvent to a solution is called diluting it, and the concentration goes down.
  • The mass of a solution equals the mass of the solvent plus the mass of the solute.
  • Warmer water, smaller pieces and stirring each make a solute dissolve faster.
  • To separate a mixture, find a property that one part has and the other does not.

Scripts, questions and quizzes are read from the course content as it stands today; the student site for this topic is here.