MS-PS1-6: Designing a Device That Releases or Absorbs Thermal Energy
In plain English: MS-PS1-6 is the NGSS middle school performance expectation that asks students to undertake a design project: construct, test and modify a device that releases or absorbs thermal energy by chemical processes, such as a hand warmer or a cold pack. Students judge each version by the amount of substance, the time and the temperature. It is usually taught in grade 7 or 8 physical science.
Undertake a design project to construct, test, and modify a device that either releases or absorbs thermal energy by chemical processes.
Clarification Statement: Emphasis is on the design, controlling the transfer of energy to the environment, and modification of a device using factors such as type and concentration of a substance. Examples of designs could involve chemical reactions such as dissolving ammonium chloride or calcium chloride.
Assessment Boundary: Assessment is limited to the criteria of amount, time, and temperature of substance in testing the device.
Next Generation Science Standards · Disciplinary Core Idea: Matter and Its Interactions · Official standard
Students act as engineers. They construct a device that releases thermal energy (a warmer) or absorbs it (a cooler) through a chemical process, test it against criteria, and modify it. A criterion (plural criteria) is a measurable goal the device must meet, such as "stays between 35 °C and 45 °C for 40 minutes". The chemical processes come from sealed, store-bought packs: in an air-activated hand warmer, iron powder reacts with oxygen from the air and releases thermal energy; in an instant cold pack, a solid (often ammonium nitrate or urea) dissolves in water and absorbs thermal energy. Students never open the packs. They change the type of pack, the amount (how many packs), the air supply and the insulation, and the teacher shows with a demonstration how the type and concentration of a dissolved substance change the result.
The NGSS Clarification Statement says: "Emphasis is on the design, controlling the transfer of energy to the environment, and modification of a device using factors such as type and concentration of a substance. Examples of designs could involve chemical reactions such as dissolving ammonium chloride or calcium chloride." The Assessment Boundary says: "Assessment is limited to the criteria of amount, time, and temperature of substance in testing the device." So every test on this page is judged by the amount of substance used, the time and the temperature. Calcium chloride and ammonium chloride appear only in a teacher demonstration and as data; students do not handle them. All data sets are invented for teaching and labeled as invented. The core lesson takes one period; building and testing the devices takes one or two more.
Learning Objectives
By the end of this lesson, students will be able to:
Construct a device that releases or absorbs thermal energy through a chemical process, and state its criteria in terms of amount, time and temperature
Test a device fairly by recording its temperature over time and comparing the results with the criteria
Use test data to modify a device, changing one factor at a time, such as the type or amount of substance or the insulation
Use data on the type and concentration of a dissolved substance to choose a recipe for a warmer or a cooler
Prior Knowledge Required
Students should already be comfortable with:
Planning and carrying out fair tests in which variables are controlled (3-5-ETS1-3)
Thermal energy moves from warmer objects to cooler ones, and temperature measures how warm something is
Signs of a chemical reaction, including a change in temperature
Reading a thermometer and making a line graph of temperature against time
Pass around two store-bought packs: a hand warmer whose outer wrapper was removed 15 minutes ago (the inner packet stays closed) and an instant cold pack that was just squeezed. Students hold each for a few seconds, then answer:
Warm-Up Prompt
"Neither pack has a battery or a plug. Where does the warmth of one come from, and where does the warmth of your hand go when you hold the other? If you had to make the warmer last longer or the cooler get colder, what would you try?"
Record the ideas (more packs, wrap it up, give it air, put it in a bag). These become the factors students test in the design project.
Direct Instruction15-20 minutes
Releasing and absorbing thermal energy. Some chemical processes release thermal energy, so the surroundings get warmer; others absorb it, so the surroundings get colder. An engineer controls how much energy moves and how fast by choosing the type of substance, its amount or concentration (how much is dissolved in a given amount of water), and how well the device is insulated from its surroundings. Use Diagram 1 for the design cycle.
Teacher demonstration. Wearing goggles and gloves, the teacher dissolves calcium chloride (the de-icing pellets sold for sidewalks) and ammonium chloride in 50 mL of water at 21.0 °C in foam cups, stirs, and records the highest or lowest temperature in 3 minutes. Students record the data from their seats. If you cannot run it, use the invented data below.
Teacher demonstration data (invented): 50 mL of water starting at 21.0 °C, foam cup
Substance
Amount dissolved
Highest or lowest temperature (°C)
Calcium chloride
5 g
33.0
Calcium chloride
10 g
44.5
Calcium chloride
15 g
54.0
Ammonium chloride
5 g
16.0
Ammonium chloride
10 g
11.8
Ammonium chloride
15 g
8.2
Choosing the type of substance
Compare the two 10 g rows of the demonstration table.
Result: Calcium chloride: 44.5 - 21.0 = +23.5 °C, so it releases thermal energy and fits a warmer. Ammonium chloride: 11.8 - 21.0 = -9.2 °C, so it absorbs thermal energy and fits a cooler.
Choosing the amount for a warmer
A warmer recipe must reach a temperature between 40 °C and 50 °C, using as little calcium chloride as possible.
Result: 5 g gives 33.0 °C (too cool), 10 g gives 44.5 °C (in range) and 15 g gives 54.0 °C (too hot). Choose 10 g. Each extra 5 g adds less than the one before (+12.0, then +11.5, then +9.5 °C), partly because a hotter cup loses energy to the room faster.
Choosing the amount for a cooler
A cooler recipe must reach 10 °C or lower.
Result: Ammonium chloride gives 16.0 °C with 5 g and 11.8 °C with 10 g, both too warm. Only 15 g reaches 8.2 °C, so the recipe needs 15 g in 50 mL: a higher concentration.
Testing for time with a store-bought cold pack (invented data)
A first-aid wrap holds an instant cold pack against a thermometer inside a towel. Criterion: 10 °C or colder for at least 15 minutes. Readings at 0, 5, 10, 15, 20, 25 and 30 minutes: 22.0, 4.5, 3.2, 5.1, 7.9, 11.0, 14.2 °C.
Result: The readings are below 10 °C from the 5-minute reading through the 20-minute reading, which is 20 - 5 = 15 minutes. The wrap just meets the criterion, so a modification such as a thicker towel layer on the outside would give it a safety margin.
Guided Practice15 minutes
A class last year designed a "warm pocket" for a crossing guard's coat: a fabric pouch holding hand warmers, with a thermometer probe inside. Their criteria were: at least 35 °C by 15 minutes, never above 45 °C (to avoid burns) during a 40-minute test, and no more than 2 hand warmers. Pairs use their invented test data and Diagram 2.
Guided practice data (invented): temperature inside four warm-pocket prototypes (°C)
Time (min)
0
5
10
15
20
25
30
35
40
A: 1 warmer, cotton pouch
22
25
27
28
28
28
28
28
27
B: 1 warmer, fleece pouch
22
27
32
35
37
38
39
39
39
C: 2 warmers, fleece pouch
22
30
38
43
46
47
48
48
48
D: 2 warmers, fleece pouch with fewer air holes
22
28
34
38
41
42
42
43
43
For each prototype, write the temperature at 15 minutes and the highest temperature in the test.
Mark each criterion as met or not met, and decide which prototypes meet all three.
For each step from A to B, B to C and C to D, name the one factor the team changed and what it did to the temperature.
Prototype D has fewer air holes than C. Use the chemistry of the hand warmer to explain why less air gives a lower temperature.
Choose the prototype you would give the crossing guard, and justify it with amount, time and temperature.
Independent Practice10-15 minutes
Each student writes a design plan for Activity 1, a "cool sleeve" that chills a 355 mL can of water using store-bought instant cold packs. The plan has four parts: (1) the criteria, written with numbers for amount (how many packs), time and temperature; (2) a labeled sketch of the first version; (3) the test: what is measured, how often, and what stays the same in every trial; (4) the one factor they will change first if the sleeve fails, and why.
Closure10 minutes
Exit ticket: "A team's hand warmer pouch reached only 30 °C. Name two different modifications, each changing just one factor, and say which criterion (amount, time or temperature) each one might help and which it might hurt." Collect the warm-up list and circle the ideas the class has now tested.
Differentiation Strategies
For Struggling Students
Give a criteria checklist with blanks to fill in: "at least ___ °C by ___ minutes; no more than ___ packs"
Provide a data table with the times already filled in, and highlight the target band on the graph paper before testing
Pair students with a partner who reads the thermometer while they record, then switch roles each round
For Advanced Students
Ask students to estimate, from the demonstration table, the amount of calcium chloride that would reach exactly 40 °C, and explain why the answer is only an estimate
Have students design a test that separates the effect of insulation from the effect of air supply in the warm pocket
Challenge students to design a device that can switch from warming to cooling by swapping one part, and write criteria for both modes
Assessment Guidance
What to Look For
Check that every criterion has a number and a unit (packs, minutes, °C). Look for test plans that keep the starting temperature, the amount of water or air and the time between readings the same. Strong modifications change one factor at a time and are backed by the test data. Listen for students who say a cold pack "adds cold": the pack absorbs thermal energy from whatever touches it.
02
Classroom Activities
3 Activities
1
Build, Test, Modify: The Cool Sleeve
40 minGroups of 3
Groups build a sleeve that holds instant cold packs against a 355 mL can of water, test how far the water temperature falls in 20 minutes, and modify the sleeve. Criteria: the water falls by at least 8 °C in 20 minutes, using no more than 2 cold packs.
Procedure
Safety: wear goggles. Never cut, puncture or open a cold pack. If one leaks, do not touch the contents; tell the teacher and wash your hands. Do not hold a cold pack against bare skin for more than a minute.
Fill the can with 355 mL of tap water and record its temperature.
Squeeze the cold pack to start it, wrap it around the can, and hold it in place with tape or a fabric strip. Add any foam or fabric layers your design calls for.
Stir gently with the thermometer probe and record the water temperature every 5 minutes for 20 minutes.
Compare with the criteria, change one factor, and test again with a fresh can of water and a new pack.
Sample Data (invented)
Every round starts with water at 22.0 °C. Temperature after 20 minutes: round 1, 1 pack, bare: 16.4 °C; round 2, 1 pack with a foam wrap outside: 14.9 °C; round 3, 2 packs with a foam wrap outside: 12.6 °C.
Discussion Questions
Find the temperature drop for each round. Which round is the first to meet both criteria?
What one factor changed from round 1 to round 2, and from round 2 to round 3?
Would the round 3 sleeve still meet the criteria on a hot day outdoors? What would you measure to find out?
Each round uses a new pack. Why would reusing the round 1 pack in round 2 make the test unfair?
Modification for Distance Learning
Students graph the sample data and write a design report. At home, a family can test a bag of frozen peas wrapped around a can as a non-chemical comparison and discuss why it is not a chemical device.
2
Lunch-Box Warmer: Amount and Air Supply
35 minGroups of 3-4
Groups use hand warmers to keep the air inside a small soft lunch box warm. Criteria: at least 30 °C from the 15-minute reading through the 45-minute reading, never above 50 °C, using no more than 3 hand warmers. They test how the number of warmers and the air supply change the result.
Procedure
Safety: never open a hand warmer packet. Hand warmers can burn skin if they are held against it or trapped in a pocket of clothing, so handle them by the edges and never tape one to your body.
Tape a thermometer probe to the inside of the lid so it hangs in the middle of the box, not touching a warmer.
Open the warmer's outer wrapper to start it, place it in the box and close the lid. Record the temperature every 15 minutes for 45 minutes.
Change one factor (the number of warmers, or the air supply) and repeat with fresh warmers.
Sample Data (invented)
Readings at 0, 15, 30 and 45 minutes. Round 1, one warmer: 22, 26, 28, 29 °C. Round 2, two warmers, lid closed normally: 22, 31, 35, 36 °C. Round 3, two warmers, box zipped shut inside a plastic bag: 22, 27, 27, 25 °C.
Discussion Questions
Which round meets every criterion? Use the readings as evidence.
Round 3 had the same number of warmers as round 2 but stayed much cooler, and its temperature fell after 30 minutes. Which reactant was running low inside the bag?
Would a third warmer help round 1's design or round 3's design more? Explain.
Challenge Variation
Groups predict, then test, whether two warmers with the lunch box wrapped in a fleece jacket stay above 30 °C until the 60-minute reading, and say which criterion the jacket helps.
3
Recipe Review: Type, Concentration and Container
25 minGroups of 3-4
Groups use invented teacher-demonstration data to choose a recipe (type of substance, amount in 50 mL of water and type of cup) for two devices, then watch the teacher test one chosen recipe. Students do not handle the chemicals.
Demonstration Data (invented)
10 g of calcium chloride, foam cup: 43.0, 44.5, 43.8, 41.2 °C at 1, 3, 5 and 10 minutes.
10 g of calcium chloride, thin plastic cup: 41.5, 40.8, 38.6, 33.9 °C at the same times.
15 g of ammonium chloride, foam cup: 9.5, 8.2, 8.6, 10.4 °C.
15 g of ammonium chloride, thin plastic cup: 10.1, 10.0, 11.2, 14.0 °C.
Design Tasks
Device 1, a hot pack: must stay at 40 °C or warmer through the 10-minute reading. Which recipe meets it?
Device 2, a cold pack: must stay at 12 °C or colder through the 10-minute reading. Which recipe meets it?
For each device, what does the foam cup do that the plastic cup does not?
Safety Note for the Teacher
Wear goggles and nitrile gloves, use a few grams at a time, and keep students behind a taped line. Calcium chloride solution gets hot and irritates skin and eyes; ammonium chloride is harmful if swallowed. Pour the solutions down the drain with plenty of water.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: The Design Cycle for a Warmer or Cooler
Engineers define the criteria (here amount, time and temperature), construct a device, test it and modify it, then test again. Changing one factor per round (the type or amount of substance, the insulation or the air supply) shows what each change does.
Diagram 2: Four Warm-Pocket Prototypes (Invented Data)
Temperature inside four prototypes over a 40-minute test, drawn to scale. The shaded band is the 35-45 °C target and the dashed line marks the 15-minute deadline. Compare each curve with the band and the deadline to decide which prototypes meet the criteria.
04
Homework Assignment
~30 min
MS-PS1-6 Homework: Testing and Improving Thermal Devices
Directions: All data are invented for practice. Judge every device only by amount, time and temperature. When you suggest a modification, change one factor at a time and say what you expect it to do.
Part 1: Define and Test (Problems 1-2)
A team tests a glove insert made with one hand warmer. Criteria: at least 35 °C by the 20-minute reading and through the 60-minute reading, never above 45 °C. Readings at 0, 10, 20, 30, 40, 50 and 60 minutes: 21, 34, 40, 42, 41, 39, 37 °C. (a) At which reading does it first reach 35 °C? (b) What is the highest temperature? (c) Does the insert meet all the criteria? (d) The team wants a 2-hour insert. What should they change about the test?
Two brands of instant cold pack, X and Y, are the same size. Plan a fair test to find which one keeps a can of water colder for longer. (a) Write one criterion each for time and temperature. (b) List three things you will keep the same. (c) Say what you will measure and how often.
Part 2: Analyze and Modify (Problems 3-4)
Teacher demonstration data: calcium chloride is dissolved in 100 mL of water that starts at 20.0 °C. The temperature rises by 5.6 °C with 4 g, 11.0 °C with 8 g and 15.8 °C with 12 g. (a) Find the highest temperature for each amount. (b) A recipe must reach at least 30 °C using as little calcium chloride as possible. Which amount should it use? (c) Would 6 g meet the criterion? Explain using the data.
A soft cooler bag for a lunch is tested with one cold pack and then with two. Temperature inside at 30, 60 and 90 minutes: one pack 12, 15, 18 °C; two packs 8, 10, 13 °C. (a) Which design keeps the bag at or below 15 °C for 60 minutes? (b) Which keeps it at or below 15 °C for 90 minutes? (c) If the lunch is eaten after 1 hour, which design would you choose, and why?
Part 3: Explain and Redesign (Problems 5-6)
A hand warmer is started, then sealed in a zip-top bag with the air pressed out. It cools to near room temperature. When the bag is opened again, it warms back up. (a) Use the chemical process inside the warmer to explain this. (b) Describe how a device could use this idea to control its temperature.
A team's warm pocket uses 2 hand warmers and reaches 52 °C at 20 minutes, above its 45 °C limit, but meets its time criterion. (a) Suggest two different modifications, each changing only one factor. (b) For each, predict the effect on the highest temperature and on how long the pocket stays warm. (c) Which would you test first, and why?
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Criteria and Fair Tests
Criteria have numbers and units for amount, time and temperature; the test keeps other factors the same
Criteria are given but one lacks a number, or the test changes two things at once
Use of Test Data
Reads temperatures and times correctly and decides, with evidence, whether each criterion is met
Reads the data with one error, or decides without citing the data
Modifications
Each modification changes one factor and is linked to the chemical process or to energy transfer, with a prediction
Modification is reasonable but not linked to the data or changes several factors
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All data are invented for practice. Choose one answer for each multiple-choice question; your score updates as you answer, and Reset quiz clears everything so you or your students can try again. Short-answer questions show a model answer.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
A device releases thermal energy by a chemical process. What happens to the temperature of the water or air around it?
Answer: B
Releasing thermal energy means energy flows out of the device into its surroundings, so they warm up. Choice A describes a device that absorbs thermal energy, like a cold pack.
Question 2 of 20 · Multiple Choice
Teacher data (invented): 8 g of substance P in 50 mL of water goes from 21 °C to 34 °C. 8 g of substance Q in 50 mL of water goes from 21 °C to 14 °C. Which should a cold pack use?
Answer: C
Q absorbs thermal energy from the water, which is what a cold pack must do. Choice A picks the larger change without checking its direction. Choice B describes a warmer. Choice D ignores the direction of the change.
Question 3 of 20 · Multiple Choice
A substance warms water when it dissolves. If you dissolve more of it in the same amount of water, the temperature change is usually:
Answer: A
More substance in the same water (a higher concentration) releases more thermal energy into the same amount of water, so the change is larger. Choice D is wrong because the amount does not change whether the process releases or absorbs energy.
Question 4 of 20 · Multiple Choice
An instant cold pack in a towel is read every 4 minutes from 0 to 24 minutes: 21.0, 6.0, 4.8, 6.9, 8.6, 9.7, 12.9 °C. For how long, from the first to the last reading below 10 °C, was it below 10 °C?
Answer: D
The readings below 10 °C are at 4, 8, 12, 16 and 20 minutes, so the span is 20 - 4 = 16 minutes. Choice A starts at 0 minutes, when the pack was still 21.0 °C. Choice B stops at the 16-minute reading, and choice C counts the whole test from 0 to 24 minutes, although the 0-minute (21.0 °C) and 24-minute (12.9 °C) readings are above 10 °C.
Question 5 of 20 · Multiple Choice
Which of these is a criterion about time?
Answer: C
Working for at least 30 minutes sets a time goal. Choice A is about the amount of substance, and choices B and D are about temperature.
Question 6 of 20 · Multiple Choice
A fair test compares 5 g and 10 g of the same substance dissolved in water. What must be kept the same?
Answer: A
Only the amount of substance should change; the water and its starting temperature must match so the comparison is fair. Choice B removes the factor being tested. Choice C is the result being measured, not something to control.
Question 7 of 20 · Multiple Choice
A lunch-box warmer with 3 hand warmers reaches 56 °C, above its 50 °C limit. Which single change is most likely to fix it?
Answer: B
Fewer warmers release less thermal energy, so the temperature stays lower. Choice A adds more energy. Choice C keeps more energy in and makes it hotter. Choice D changes the test, not the device.
Question 8 of 20 · Multiple Choice
In a cold pack test, the water starts at 21.5 °C and ends at 9.0 °C. By how much did the temperature fall?
Answer: D
21.5 - 9.0 = 12.5 °C. Choice A adds the two temperatures instead of subtracting. Choice B is a subtraction error (21.5 - 10.0). Choice C is the final temperature, not the change.
Question 9 of 20 · Multiple Choice
Criteria: at least 35 °C by 10 minutes, never above 45 °C, no more than 2 warmers. Design W: 1 warmer, 33 °C at 10 min, highest 40 °C. Design X: 2 warmers, 38 °C at 10 min, highest 44 °C. Design Y: 3 warmers, 41 °C at 10 min, highest 49 °C. Design Z: 2 warmers, 36 °C at 10 min, highest 47 °C. Which design meets all the criteria?
Answer: B
X is warm enough at 10 minutes, stays under 45 °C and uses 2 warmers. W is too cool at 10 minutes. Y uses too many warmers and gets too hot. Z gets too hot.
Question 10 of 20 · Multiple Choice
Why might a cold pack device be wrapped in foam on the outside?
Answer: A
Foam is an insulator: it slows the flow of thermal energy from the warm room into the cold device, so the device stays cold longer. Choice C is a common error, since "cold" is not a substance that can be added. Choice D would make the device useless.
Question 11 of 20 · Multiple Choice
A team reuses a hand warmer that already ran all day yesterday. Today, in the same pouch, it barely warms up. What is the best explanation?
Answer: C
A hand warmer releases thermal energy while its iron powder reacts with oxygen from the air. After a full day, most of the iron has already reacted, so little reactant is left and little thermal energy is released: the amount of substance limits the device. Choice A is wrong because a hand warmer has no battery. Choice B treats cold as something that can be stored, but only thermal energy moves. Choice D is wrong because the salt does not melt at these temperatures, and the packet is still sealed.
Question 12 of 20 · Multiple Choice
Three trials of the same cold pack recipe drop the temperature by 11.8 °C, 12.4 °C and 12.1 °C. What is the mean (average) drop?
Answer: D
Mean = (11.8 + 12.4 + 12.1) ÷ 3 = 36.3 ÷ 3 = 12.1 °C. Choice A is the largest value, choice B is the sum without dividing, and choice C is the range (12.4 - 11.8).
Question 13 of 20 · Multiple Choice
Two identical instant cold packs are squeezed at the same moment. Pack 1 is wrapped around a can of tap water; pack 2 lies alone on a foam sheet in the air. After 10 minutes, pack 1 is warmer than pack 2. What is the best explanation?
Answer: A
Both packs absorb thermal energy as their solid dissolves, but the can of water touching pack 1 passes thermal energy into it much faster than the air passes it into pack 2, so pack 1 warms up sooner. Choice B is wrong because a cold pack absorbs thermal energy; it does not release it. Choice C treats cold as something that can move, but only thermal energy flows, from the warmer water into the colder pack. Choice D is wrong because the packs are identical and were started together: the only difference is what touches them.
Question 14 of 20 · Multiple Choice
In a hot-pack test, the temperature rises from 21 °C to 39 °C in the first 6 minutes. What is the average rise per minute?
Answer: C
The rise is 39 - 21 = 18 °C in 6 minutes, and 18 ÷ 6 = 3 °C per minute. Choice A is the total rise, not the rate. Choice B divides the final temperature by the time (39 ÷ 6), and choice D divides the starting temperature by the time (21 ÷ 6).
Question 15 of 20 · Short Answer
Plan a test for a hand-warmer pouch that must stay between 35 °C and 45 °C for 30 minutes. Say what you will measure, how often, and two things you will keep the same in every trial.
Measure the temperature inside the pouch with a probe every 5 minutes for at least 30 minutes. Keep the same: the starting room temperature, the number and brand of hand warmers, the position of the probe and the pouch material (unless that is the factor being tested). The pouch passes if every reading from the start of the target time to 30 minutes is between 35 °C and 45 °C.
Question 16 of 20 · Short Answer
Criteria for a drink cooler: the water must drop at least 8 °C in 20 minutes, using no more than 2 cold packs. Design 1 (1 pack) drops 6.8 °C. Design 2 (2 packs) drops 9.1 °C. Which design meets the criteria? Suggest a change that could help Design 1 meet them without adding a pack.
Design 2 meets both criteria (9.1 °C is at least 8 °C, and it uses 2 packs). Design 1 falls short by 8 - 6.8 = 1.2 °C. One change: wrap foam or fabric around the outside of Design 1 so less thermal energy flows in from the room, or press the pack more tightly against the can.
Question 17 of 20 · Short Answer
In 100 mL of water, 6 g of ammonium chloride lowers the temperature by 3.2 °C. Predict the drop with 12 g, and explain why a real test might give a little less than your prediction.
Twice the amount absorbs about twice the energy, so predict about 2 × 3.2 = 6.4 °C. The real drop may be a little less because, as the water gets colder, more thermal energy flows in from the room during the test.
Question 18 of 20 · Short Answer
An instant cold pack reaches 3 °C in 2 minutes but is back to 18 °C after 40 minutes. Explain why it warms up again, and name one way to make it stay cold longer.
Once the solid has finished dissolving, the pack stops absorbing energy, and thermal energy from the warmer surroundings flows into it until it nears room temperature. To make it stay cold longer: insulate the outside, or use a larger pack (more substance).
Question 19 of 20 · Short Answer
Criteria for a cold pack: 5 °C or colder by the 5-minute reading, and 10 °C or colder for at least 15 minutes. Readings at 0, 5, 10, 15, 20 and 25 minutes: 22.0, 3.9, 4.6, 7.5, 10.8, 13.9 °C. Does it meet each criterion?
First criterion: met, since it reads 3.9 °C at 5 minutes. Second criterion: not met: it is at or below 10 °C only from 5 to 15 minutes, which is 10 minutes, and it reads 10.8 °C at 20 minutes.
Question 20 of 20 · Short Answer
Your cool sleeve lowers the water temperature by only 5 °C in 20 minutes, but the criterion is 8 °C. Describe two modifications, each changing one factor, and say how you would test whether each one worked.
Possible changes: add a second cold pack (more substance, if the criteria allow 2) or add insulation around the outside of the sleeve. Test each one separately with a fresh pack, the same amount of water and the same starting temperature, reading the temperature every 5 minutes for 20 minutes, and check whether the drop reaches 8 °C or more.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-PS1-6 mean?
MS-PS1-6 asks middle school students to carry out a design project: build, test and improve a device that releases or absorbs thermal energy through a chemical process, such as a hand warmer or a cold pack. The code means Middle School, Physical Science, core idea 1 (Matter and Its Interactions), performance expectation 6. It is also an engineering standard, so students follow a design cycle.
What grade is MS-PS1-6 taught in?
It is a grades 6-8 standard. Many schools teach it in grade 7 or 8, after a unit on chemical reactions, because students need to know that reactions can release or absorb energy before they design with them.
What is the assessment boundary for MS-PS1-6?
Assessment is limited to the criteria of amount, time and temperature of substance in testing the device. Students judge a design by how much substance it uses, how long it works and what temperature it reaches. Cost, appearance and other criteria can be discussed but are beyond this standard's assessment.
Is dissolving a chemical process?
For this standard, yes: the Clarification Statement names dissolving ammonium chloride or calcium chloride as examples. Dissolving these salts releases or absorbs thermal energy because particles separate and new attractions form with water. In high school, students look more closely at which changes count as reactions.
Can students use calcium chloride or ammonium chloride themselves?
On this page they do not. Both are named in the Clarification Statement, but calcium chloride solution gets hot and irritates skin and eyes, and ammonium chloride is harmful if swallowed. Here the teacher runs a short demonstration with goggles and gloves, and students design with sealed, store-bought hand warmers and cold packs, which they never open.
How do hand warmers and cold packs work?
An air-activated hand warmer holds iron powder, salt, water and carbon; once the wrapper is opened, iron reacts with oxygen from the air and releases thermal energy for several hours. An instant cold pack holds a solid, often ammonium nitrate or urea, and a pouch of water; squeezing it breaks the pouch, and the dissolving solid absorbs thermal energy.
What can students change to modify their device?
The type of substance (warming or cooling), its amount or concentration, the air supply for a hand warmer, and the insulation that controls how fast energy moves to or from the surroundings. A good design round changes only one of these at a time, so the test data show what that change did.
What mistakes do students often make in this design project?
Some change two things at once and cannot tell which one helped. Others write criteria without numbers, such as "stays warm", or reuse a pack that has already been used. Many say a cold pack "gives off cold"; the pack absorbs thermal energy from whatever touches it.
How long does an MS-PS1-6 design project take?
Plan on one period to introduce the chemistry, the criteria and the demonstration, and one or two more to build, test and modify. Each hand-warmer or cold-pack test takes 20 to 45 minutes, so groups can run a test while they plan the next round.
How does MS-PS1-6 connect to other standards?
It pairs naturally with MS-PS3-3, where students design a device that minimizes or maximizes thermal energy transfer, and with the engineering standards MS-ETS1-3 and MS-ETS1-4 on testing and improving designs. In high school, HS-PS1-4 explains why some reactions release energy and others absorb it, using bond energy.
07
Related Standards
5 standards
These standards connect to MS-PS1-6: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
3-5-ETS1-3Prerequisite
Plan and carry out fair tests that control variables to find what to improve in a prototype
Lesson coming soon
Alongside
MS-PS3-3Parallel
Design, construct and test a device that minimizes or maximizes thermal energy transfer
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