HS-PS3-3: Designing, Building and Refining an Energy Conversion Device
In plain English: HS-PS3-3 is the NGSS high school performance expectation that asks students to design, build and refine a device that converts one form of energy into another within given constraints, such as a generator, a solar oven or a wind turbine. Students test the device, compare its total energy output with the energy put in, and use the results to improve it. It is usually taught in Physics or Physical Science.
Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.
Clarification Statement: Emphasis is on both qualitative and quantitative evaluations of devices. Examples of devices could include Rube Goldberg devices, wind turbines, solar cells, solar ovens, and generators. Examples of constraints could include use of renewable energy forms and efficiency.
Assessment Boundary: Assessment for quantitative evaluations is limited to total output for a given input. Assessment is limited to devices constructed with materials provided to students.
Next Generation Science Standards · Disciplinary Core Idea: Energy · Official standard
Students work as engineers: they design a device that turns one form of energy into another, build it from a kit of provided materials, test it, and refine it using their own data. The main device is a falling-mass generator, in which a descending mass spins a small geared motor that lights an LED. Solar ovens, wind turbines, solar panels and Rube Goldberg chains give further practice. Every test compares the total useful output with the energy put in, and every refinement is judged against the criteria and constraints of the design brief.
The NGSS Clarification Statement says: "Emphasis is on both qualitative and quantitative evaluations of devices. Examples of devices could include Rube Goldberg devices, wind turbines, solar cells, solar ovens, and generators. Examples of constraints could include use of renewable energy forms and efficiency." The Assessment Boundary says: "Assessment for quantitative evaluations is limited to total output for a given input. Assessment is limited to devices constructed with materials provided to students." So every calculation on this page compares one total output energy with one input energy, and every build uses only the kit. All data sets are invented for teaching. The page uses g = 9.8 m/s² and the specific heat of water, 4186 J/(kg·°C).
Learning Objectives
By the end of this lesson, students will be able to:
Write a design brief for an energy conversion device that names the energy input, the useful output, the criteria for success and the constraints
Build a working device from provided materials and describe the chain of energy conversions inside it
Measure the total useful output of a device for a given input and express it as an efficiency
Refine a device by changing one design feature at a time and using test data to decide whether the change helped
Evaluate a design against constraints such as materials, cost, renewable energy sources and a target efficiency
Prior Knowledge Required
Students should already be comfortable with:
Designing and testing a device that controls thermal energy transfer MS-PS3-3
Energy transfer when the kinetic energy of an object changes MS-PS3-5
Gravitational energy mgh, and electrical energy as voltage × current × time
Using units to guide a multi-step calculation HSN.Q.A.1
Pass around a hand-crank flashlight. Let each student crank it for a few seconds, then ask:
Warm-Up Prompt
"Trace the energy from your arm to the light. Name every form it takes on the way. Then feel the flashlight: where did the energy go that did not become light? If you had to build a better one, what would you change first?"
Record the chain on the board (chemical energy in muscles, kinetic energy of the crank, electrical energy, light, thermal energy). Point out that the flashlight gets warm and makes noise: those are outputs too, just not useful ones. Tell students they will design, build and refine a device of their own.
Direct Instruction15-20 minutes
The design cycle and the energy test. An engineer starts with a design brief. The criteria say what counts as success (light an LED for as long as possible, heat water as much as possible). The constraints are limits (only the kit materials, a drop height of 1.00 m, renewable energy only, 20 minutes to build). Then the cycle is: design, build, test, refine, test again. The quantitative test is always the same: measure the total useful output energy for a known input energy. Efficiency = useful output ÷ input, which is always less than 100% because some energy spreads out as thermal energy and sound. Use Diagram 1 with the first example.
Falling-mass generator
A 1.0 kg mass on a string falls 1.5 m and turns a small geared DC motor used as a generator. A multimeter reads 2.0 V and 0.060 A across the resistor during the 24.5 s the mass takes to fall.
Result: Input = mgh = 1.0 × 9.8 × 1.5 = 14.7 J. Output = VIt = 2.0 × 0.060 × 24.5 = 2.94 J. Efficiency = 2.94 ÷ 14.7 = 0.20, or 20%.
Solar oven (thermal output)
A pizza-box oven with a 0.40 m × 0.40 m window heats 0.500 kg of water from 22 °C to 46 °C in 45 minutes. A solar power meter reads 850 W/m² the whole time.
Result: Input = 850 W/m² × 0.16 m² × 2700 s = 367,200 J. Output = mcΔT = 0.500 × 4186 × 24 = 50,232 J. Efficiency ≈ 13.7%.
Rube Goldberg chain
A 0.20 kg bag of sand falls 0.50 m and starts a chain of dominoes, a marble run and a lever. The last step lifts a 0.050 kg flag 0.20 m.
Result: Input = 0.20 × 9.8 × 0.50 = 0.98 J. Useful output = 0.050 × 9.8 × 0.20 = 0.098 J. Efficiency = 10%: each step hands on less energy than it received.
Refining a wind turbine
A box fan draws 45 W (plug-in watt meter) for 120 s. Version 1 (flat card blades) gives 1.8 V and 0.10 A. Version 2 (the same blades twisted to an angle) gives 3.0 V and 0.20 A.
Result: Input = 45 × 120 = 5400 J. Output 1 = 1.8 × 0.10 × 120 = 21.6 J (0.40%). Output 2 = 3.0 × 0.20 × 120 = 72 J (about 1.3%). Same input, so the refinement more than tripled the output.
After each example, ask: "What is the input, what is the useful output, and where did the rest go?" Stress that a fair comparison of two versions needs the same input (same mass and drop, same fan setting, same sunlight reading), and that the wind turbine numbers describe the whole fan-and-turbine system, so they are small.
Guided Practice15 minutes
Pairs analyze invented test data from one group's falling-mass generator. Every test used the same input: a 0.50 kg mass falling 1.20 m. The group changed one feature per test. Students compute each output and efficiency, then compare with Diagram 2.
Guided practice data: generator prototypes (invented)
Prototype
Change made
Voltage (V)
Current (A)
Fall time (s)
P1
Starting design, 1 cm spool
1.2
0.035
14.0
P2
Spool radius 2 cm
2.1
0.060
7.0
P3
2 cm spool, string guide added so the string stops rubbing
2.4
0.070
6.3
P4
Spool radius 3 cm, guide kept
2.8
0.070
4.2
Find the input energy: mgh = 0.50 × 9.8 × 1.20 = 5.88 J for every test.
Find each output, VIt, and each efficiency. P1 gives 1.2 × 0.035 × 14.0 = 0.588 J, which is 10.0% of the input.
Which change helped, which hurt, and how do you know the comparison is fair?
Write a one-sentence recommendation for the next test, naming the one feature you would change and why.
Independent Practice10-15 minutes
Each student writes a design brief for a sunlight-powered device built only from a kit (one 10 cm × 10 cm mini solar panel, one small geared motor, card, tape, string and a spool). The brief lists the energy conversions, two criteria, three constraints, a labeled sketch and a test plan that keeps the input the same between versions.
Students then analyze one invented test of the panel alone: the solar power meter reads 900 W/m² on the 0.010 m² panel for 60 s, and the panel delivers 5.0 V and 0.18 A to a resistor. They find the input (540 J), the output (54 J) and the efficiency (10%), and explain what this means for how much energy is left to run the motor.
Closure5 minutes
Exit ticket: "A falling mass gives your generator 6.0 J, and you measure 0.90 J of electrical output. What is the efficiency? Name one refinement you would test next and the one thing you would keep the same." (15%.) Collect the tickets to form build groups with a mix of ideas.
Differentiation Strategies
For Struggling Students
Give a design brief template with the headings Input, Useful Output, Criteria, Constraints, Sketch and Test Plan already filled in for one example
Provide a calculation table with columns for V, I, t, VIt, mgh and output ÷ input so students fill in one column at a time
Start with the falling-mass generator only, and give a list of three possible refinements to choose from
For Advanced Students
Ask students to repeat each test three times, report the spread of the outputs, and decide whether a refinement's gain is larger than that spread
Have students trace every loss in the generator chain and design a test that isolates one of them, for example running the motor with and without the gears
Challenge students to meet two competing criteria at once, such as the highest output with the fewest kit parts, and justify the trade-off
Assessment Guidance
What to Look For
Check that design briefs separate criteria (what success looks like) from constraints (limits). Look for tests that keep the input the same and change one feature at a time. Check that students compute output and input in joules and never report an output larger than the input without questioning the measurement. Listen for refinement decisions that cite data, not appearance.
02
Classroom Activities
3 Activities
1
Falling-Mass Generator Challenge
30 minGroups of 3
Groups design and build a generator that turns the gravitational energy of a 0.50 kg mass falling 1.00 m (an input of 4.9 J) into as much electrical energy as possible. They then test it, make one refinement and test again.
Design Brief
Criteria: the LED lights during the fall, and the electrical output is as large as possible.
Constraints: only the kit (one small geared DC motor, a set of spools of 1, 2 and 3 cm radius, 1.5 m of string, a 0.50 kg slotted mass, an LED, a 100 Ω resistor, card, tape, two clamps), a drop of exactly 1.00 m, and 20 minutes to build.
Before building, each group sketches the design and writes the energy chain from the falling mass to the LED.
Build and Test
Clamp the motor to the table edge, attach a spool to its shaft and wind the string on it. Connect the motor to the LED and resistor in series.
Release the mass from rest. One student reads the multimeter voltage across the resistor, one reads the current, one times the fall.
Compute the output VIt and compare it with the 4.9 J input. Make one refinement (spool size, string alignment, how the motor is clamped) and repeat the same test.
Safety: wear goggles, put a foam pad under the mass, and keep hands and feet out from under it.
Discussion Questions
Which part of your device lost the most energy? What evidence (warmth, noise, slipping string) points to it?
Your refinement changed the output. How do you know the change came from the refinement and not from a different input?
If a group reports more than 4.9 J of output, what should they check first?
Modification for Distance Learning
Students analyze the guided-practice data set, then sketch a design and a test plan for a hand-crank generator and post it to the class board for peer feedback.
2
Solar Oven Build and Refine
35 minGroups of 3-4
Groups build a solar oven from a pizza box and heat 0.200 kg of water in a small black can. They measure the thermal energy gained by the water, compare it with the sunlight entering the 0.12 m² window, refine the oven and test again under the same sunlight reading. Solar energy is renewable, which is one of the constraints.
Procedure
Line the box with black paper, seal the window with plastic wrap and angle a foil flap so sunlight enters the window. Keep the flap the same in both tests.
Record the water temperature every 5 minutes for 30 minutes and the solar power meter reading at the start and end.
Refine one feature (for example, pack newspaper around the inner box as insulation) and repeat when the meter shows the same reading.
Safety: never look at the sun or at the glare off the foil, handle the can with an oven mitt, and keep water below 60 °C.
Sample Data (invented)
Meter reading 800 W/m² during both tests, so the input is 800 × 0.12 × 1800 = 172,800 J each time. Version 1: water from 22.0 °C to 33.5 °C. Version 2 (newspaper insulation added): water from 22.0 °C to 41.0 °C. Students compute mcΔT for each version (about 9,630 J and 15,910 J) and the efficiencies (about 5.6% and 9.2%).
Discussion Questions
The insulation raised the output by about 65%. Why was it important that the meter read 800 W/m² in both tests?
If the water warms more slowly near the end of a test, where is the extra sunlight energy going?
Your design brief says the oven must use a renewable energy form. Name one advantage and one limit of that constraint.
Challenge Variation
Groups may use one extra sheet of foil to add a second reflector flap. Because the flap collects sunlight from outside the window, they must redefine the input area before comparing efficiencies.
3
Design Review Stations
20 minGroups of 3-4
Three stations each show invented test results from a different device. At each station, groups decide which version to keep, justify the choice with the data and the constraints, and propose the next test. Groups rotate every 6 minutes.
Station Data
Station 1, mini solar panel tilt (same sunny hour): output 0.52, 0.78, 0.86 and 0.80 W at tilts of 0°, 30°, 45° and 60° from the ground.
Station 2, wind turbine blade count (same fan, 2700 J in over 60 s): output 16.2, 24.3, 27.0 and 21.6 J with 2, 3, 4 and 6 blades. The kit card is enough for at most 6 blades.
Station 3, Rube Goldberg chain: a 0.15 kg weight falls 1.0 m (1.47 J in). The estimated energy passed on is 1.10 J after the ramp, 0.62 J after the lever and 0.45 J in the final lift.
Discussion Questions
At Station 1, which tilt gave the largest output, and would you test 40° or 50° next?
At Station 2, 6 blades gave less output than 4. Suggest a reason, and say whether the constraint on card limits your choice.
At Station 3, which step lost the most energy? What refinement would you try on that step first?
Modification for Distance Learning
Post each station as a slide. Groups meet in breakout rooms and submit one decision card per station on a shared document.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Energy Accounting for a Falling-Mass Generator
The first worked example drawn to scale: the 14.7 J input bar and the output bar have the same length. Only 2.94 J (20%) leaves as useful electrical energy; the other 11.76 J spreads out as thermal energy and sound. Refinements aim to make the green part longer for the same input.
Diagram 2: Refinement Data for Four Generator Prototypes
Efficiency of the four guided-practice prototypes, drawn to scale. Every test used the same 5.88 J input and changed one feature. The larger spool and the string guide helped (P2, P3); the 3 cm spool lowered the output (P4), so the group keeps P3.
04
Homework Assignment
~30 min
HS-PS3-3 Homework: Designing and Refining Energy Devices
Directions: All data sets are invented for practice. Use g = 9.8 m/s² and c = 4186 J/(kg·°C) for water. Every device is built only from the kit materials named. Show each calculation with units, and end each problem with a one- or two-sentence decision that cites your numbers.
Part 1: Output for a Given Input (Problems 1-2)
A group's generator is driven by a 0.60 kg mass that falls 1.40 m. During the 16 s fall, the multimeter reads 1.5 V and 0.045 A. (a) Find the input energy. (b) Find the electrical output. (c) Find the efficiency. (d) Name one place the missing energy went and the evidence you could look for.
Two solar ovens are tested side by side for 40 minutes, each with a 0.12 m² window and 0.30 kg of water. The solar power meter reads 750 W/m². Oven A warms its water by 12 °C and oven B by 18 °C. (a) Find the input for each oven. (b) Find each output. (c) The design brief requires an efficiency of at least 8%. Which oven meets it?
Part 2: Designing Within Constraints (Problems 3-4)
Design a device that uses sunlight to lift a paper cup of paper clips (total mass 0.020 kg) by 0.30 m. The kit is one mini solar panel, one small geared motor, a spool, string, card and tape. (a) Write two criteria and three constraints. (b) Sketch the device and label each energy conversion. (c) Find the minimum useful output energy the lift needs. (d) If the whole device turns 3% of the sunlight on the panel into lifting, how much sunlight energy must reach the panel for one lift?
Two wind turbine designs are tested with the same fan, which uses 3600 J during each test. Design X (3 blades) produces 30 J and uses 4 material credits. Design Y (5 blades) produces 36 J and uses 7 material credits. The budget is 6 credits. (a) Find the efficiency of each design. (b) Which design meets every constraint? (c) Explain why the design with more output is not the right choice here.
Part 3: Refining with Test Data (Problems 5-6)
A generator driven by a 0.75 kg mass falling 1.00 m is tested with four resistors, one at a time: 10 Ω gives 0.51 J, 47 Ω gives 1.03 J, 100 Ω gives 1.18 J and 220 Ω gives 0.88 J of output. (a) Find the input energy. (b) Which resistor gives the best efficiency, and what is it? (c) Why must the group change only the resistor between these tests? (d) Suggest the next resistor value to test and explain why.
A group reports that the last step of its Rube Goldberg device lifted a 0.10 kg block by 0.50 m, and that the chain was started by a 0.30 kg weight falling 0.15 m. (a) Compute the input and the output. (b) Explain why the report cannot be right. (c) Name two things the group should recheck, including any energy source they may have left out.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Energy Input and Output
Input and useful output computed in joules with units, and efficiency found as output ÷ input
Correct method with one calculation or unit error
Design Brief
Criteria and constraints are separate, specific and tied to the kit; the energy chain is complete
Criteria and constraints are mixed together or vague
Refinement Decision
Decision uses a fair comparison (same input, one change) and cites the numbers
Decision stated but the data or the fairness of the test is not discussed
Constraints and Trade-offs
Checks every constraint, including cost or renewable energy, before choosing
Chooses by output alone
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All data sets are invented. Use g = 9.8 m/s² and c = 4186 J/(kg·°C) for water. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again.
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 mini solar panel powers a small fan. What energy conversion happens in the panel itself?
Answer: A
A solar cell absorbs light and produces an electric current. Choice B describes the fan motor, the next step in the chain. Choice D describes a battery, which the panel does not contain.
Question 2 of 20 · Multiple Choice
In a design brief for a solar oven, which statement is a constraint?
Answer: D
A constraint is a limit the design must stay within, such as a cap on how much of a material may be used. Choices A and B describe goals, which are criteria. Choice C is a vague criterion that is hard to measure.
Question 3 of 20 · Multiple Choice
A 2.5 kg mass falls 0.80 m and drives a generator that delivers 2.45 J of electrical energy. What is the efficiency?
Answer: C
Input = mgh = 2.5 × 9.8 × 0.80 = 19.6 J, and 2.45 ÷ 19.6 = 0.125 = 12.5%. Choice A forgets to multiply by 100. Choice B is the share that was lost, not the output. Choice D divides the input by the output; an efficiency above 100% is impossible.
Question 4 of 20 · Multiple Choice
In a solar oven test, 0.40 kg of water warms by 15 °C. How much thermal energy did the water gain?
Answer: B
Q = mcΔT = 0.40 × 4186 × 15 = 25,116 J. Choice A multiplies only the mass and the temperature change and drops the specific heat. Choice C leaves out the temperature change, and choice D leaves out the mass.
Question 5 of 20 · Multiple Choice
A group wants to know whether twisting its turbine blades raises the output. Which plan is a fair test?
Answer: D
A fair test changes one feature and keeps the input the same, so any change in output comes from the feature. Choices A and B change the input as well as the blades, so the effect of the twist cannot be separated. Choice C replaces a measurement with an opinion.
Question 6 of 20 · Multiple Choice
A box fan uses 3000 J while a small turbine in front of it produces 36 J of electrical energy. What is the efficiency of the fan-and-turbine system?
Answer: C
36 ÷ 3000 = 0.012 = 1.2%. Choice A is the share lost, not the useful share. Choice B moves the decimal point one place. Choice D comes from dividing 3000 by 36 and reading the result as a percent.
Question 7 of 20 · Multiple Choice
Which result best shows that a refinement improved a generator?
Answer: A
Choice A keeps the input the same and repeats each test; the gain (about 0.2 J) is much larger than the spread within each set of trials. Choice B changed the input, so the gain may come from the higher drop. Choice D's gain of 0.01 J is smaller than the normal trial-to-trial spread.
Question 8 of 20 · Multiple Choice
A 0.020 m² solar panel receives 1000 W/m² of sunlight for 60 s and delivers 3.0 V and 0.50 A to a resistor for that time. What is its efficiency?
Answer: B
Input = 1000 × 0.020 × 60 = 1200 J and output = 3.0 × 0.50 × 60 = 90 J, so 90 ÷ 1200 = 7.5%. Choice A reports the electrical power, 1.5 W, as if it were a percent. Choice C divides the input by the output. Choice D moves the decimal point.
Question 9 of 20 · Multiple Choice
A group reports that its generator produced 5.2 J of electrical energy from a 4.9 J falling mass. What is the best conclusion?
Answer: D
Energy is conserved, so the useful output cannot be larger than the total input. The group should recheck the meter readings, the timing and the drop height, and check whether someone pushed the mass. Choices B and C contradict conservation of energy.
Question 10 of 20 · Multiple Choice
A design brief says the device must use a renewable energy source. Which device meets this constraint?
Answer: A
Wind is a renewable energy source. Choice B uses chemical energy stored in batteries, which is used up. Choice C stores energy that a person put in, and choice D depends on how the grid generates electricity, so it does not meet the constraint on its own.
Question 11 of 20 · Multiple Choice
In a Rube Goldberg device, a falling weight puts in 0.60 J, and the last step lifts a flag using 0.15 J. Where did most of the other 0.45 J go?
Answer: B
Energy is conserved but spreads out: friction in each step warms the parts slightly, and collisions make sound. Choice A says energy is destroyed, which conservation rules out. Choices C and D ignore that the weight has already fallen.
Question 12 of 20 · Multiple Choice
A generator's multimeter reads 2.5 V and 0.040 A for 12 s. What is the electrical output energy?
Answer: D
Energy = VIt = 2.5 × 0.040 × 12 = 1.2 J. Choice A is the power VI, not the energy. Choice B multiplies the voltage by the time and leaves out the current. Choice C multiplies the current by the time and leaves out the voltage.
Question 13 of 20 · Multiple Choice
A team is designing a wind turbine. Which statement is a criterion?
Answer: C
A criterion describes what success looks like, here the largest output. Choices A, B and D are limits on materials, time and size, which makes them constraints.
Question 14 of 20 · Multiple Choice
Prototype A produces 2.0 J from a 10 J input. Prototype B produces 2.7 J from a 15 J input. Which statement is correct?
Answer: A
A: 2.0 ÷ 10 = 20%. B: 2.7 ÷ 15 = 18%. Choice B judges by the output alone and ignores the input. Choice D is wrong because efficiency divides by the input, which is what makes different inputs comparable.
Question 15 of 20 · Short Answer
A 0.90 kg mass falls 1.10 m and drives a generator. During the 15 s fall, the multimeter reads 1.8 V and 0.050 A. Find the input, the output and the efficiency.
Your solar oven reached a lower water temperature than your target. Plan a refinement test: what one feature will you change, what will you keep the same, and what will you measure?
Sample answer: change one feature, for example add a second layer of plastic wrap over the window. Keep the same water mass, can, test time and sunlight reading (test at the same time of day and check the solar power meter). Measure the starting and final water temperatures and compute mcΔT for both versions; repeat each test if time allows. The refinement helped only if the output rises by more than the spread between repeated tests.
Question 17 of 20 · Short Answer
A solar oven's 0.090 m² window receives 800 W/m² for 20 minutes, and 0.25 kg of water in it warms by 8.0 °C. Find the input, the output and the efficiency.
Input = 800 × 0.090 × 1200 s = 86,400 J. Output = 0.25 × 4186 × 8.0 = 8,372 J. Efficiency = 8,372 ÷ 86,400 ≈ 9.7%.
Question 18 of 20 · Short Answer
Each step of a Rube Goldberg chain passes on 80% of the energy it receives. What share of the input reaches the end of a 3-step chain, and of a 6-step chain? What does this mean for the design?
3 steps: 0.8³ = 0.512, about 51%. 6 steps: 0.8⁶ ≈ 0.262, about 26%. Every added step is another place for energy to spread out as thermal energy and sound, so a longer chain needs a larger input or more efficient steps to finish its task.
Question 19 of 20 · Short Answer
A box fan uses 40 W for 90 s. The turbine in front of it gives 1.6 V and 0.12 A for the same 90 s. Find the efficiency of the whole system and give two reasons it is so low.
Input = 40 × 90 = 3600 J. Output = 1.6 × 0.12 × 90 = 17.28 J. Efficiency = 17.28 ÷ 3600 = 0.48%. Reasons: the fan motor turns much of its input into thermal energy and sound; much of the moving air misses the blades or passes through without slowing; the turbine's generator and bearings lose energy to friction.
Question 20 of 20 · Short Answer
Your generator turns 12% of a 5.0 J input into electrical energy. The design brief sets a target of 15%. How much more output do you need, and name two refinements you could test?
At 12% the output is 0.60 J; the target is 0.15 × 5.0 = 0.75 J, so you need 0.15 J more. Refinements to test one at a time: a different spool size, a string guide to stop rubbing, a tighter clamp so the motor does not wobble, or a different resistor. Keep the same mass and drop height for every test.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does HS-PS3-3 mean?
HS-PS3-3 asks students to design, build and refine a device that converts one form of energy into another while meeting given constraints. It joins physics (energy conversion) with engineering (the design cycle). The code means High School, Physical Science, core idea 3 (Energy), performance expectation 3.
Is HS-PS3-3 physics or engineering?
It is both: the content is energy conversion from physics, and the practice is engineering design. It is usually taught in Physics or Physical Science, often as a project that takes several class periods. Many teachers pair it with the HS-ETS1 engineering design standards.
What is the assessment boundary for HS-PS3-3?
Quantitative evaluations are limited to the total output for a given input, and devices must be built from materials provided to students. So students compare one output energy with one input energy (an efficiency) and do not need power curves or detailed loss models. Anything beyond that is beyond this standard.
What devices can students build for HS-PS3-3?
The Clarification Statement names Rube Goldberg devices, wind turbines, solar cells, solar ovens and generators. Low-cost options include a falling-mass generator made with a small geared motor, a pizza-box solar oven, card-blade turbines in front of a box fan, and mini solar panels driving a small motor.
How do you calculate the efficiency of a student-built device?
Divide the useful output energy by the input energy and multiply by 100. For example, if a falling mass gives a device 8.0 J and the device delivers 1.4 J of electrical energy, the efficiency is 1.4 ÷ 8.0 = 17.5%. Electrical energy is voltage × current × time, gravitational energy is mgh, and thermal energy gained by water is mcΔT.
What is the difference between criteria and constraints?
Criteria describe what success looks like; constraints are the limits the design must stay within. "Heat the water as much as possible" is a criterion. "Use only the kit materials" and "use a renewable energy source" are constraints. The NGSS example constraints for HS-PS3-3 are renewable energy forms and efficiency.
Why is the useful output always less than the energy put in?
Energy is conserved, but in every real device some of it spreads out as thermal energy (from friction and electrical resistance) and as sound. That energy is still there, just not in a useful form. That is why every measured efficiency is below 100%.
How many times should students refine their device?
At least one full test, refine and retest cycle is needed to show refinement, and two cycles are better if time allows. Each refinement should change one feature and keep the input the same, so the data show whether that feature helped.
Can HS-PS3-3 be done online or at home?
Yes, with a mailed or home kit of provided materials, since the Assessment Boundary limits the standard to devices built from materials given to students. Students can film their tests and share measurements. Simulations and shared data sets work for analysis practice, but the standard expects a real build.
What comes after HS-PS3-3?
HS-ETS1-3 asks students to evaluate solutions using prioritized criteria and trade-offs, and HS-ESS3-2 asks them to evaluate competing designs for energy resources using cost-benefit ratios. Both build on the design, test and refine cycle of HS-PS3-3.
07
Related Standards
5 standards
These standards connect to HS-PS3-3: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
MS-PS3-3Prerequisite
Design, build and test a device that minimizes or maximizes thermal energy transfer
NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.
