HS-PS3-3: Designing an Energy Conversion Device
Also called NGSS HS-PS3-3 · Topic: Energy · Physical Science
The Official Wording
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.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-PS3-3 Means in Plain English
Students design, build and improve a working device that changes energy from one form to another, such as a wind turbine, a solar oven or a chain-reaction machine. They work within limits on materials, size or cost, and judge their device by measuring it.
Measurements compare total energy out with energy in, using only the materials the class provides. This builds on 4-PS3-4 and MS-PS3-3, weighs trade-offs as in HS-ETS1-3, and connects to choosing energy sources in HS-ESS3-2.
HS-PS3-3 I Can Statements
- I can design a device that turns one energy form into another.
- I can measure the energy my device puts out.
- I can improve my design using test results.
HS-PS3-3 Worked Example
A model wind turbine challenge where teams test blade designs in front of a fan.
Which blade design gets the most electrical power from the same breeze?
Set It Up: A box fan on low, a small DC motor used as a generator, a cardboard hub, card blades, a 100 ohm resistor and a multimeter.
- Define the problem and limits: blades up to 15 cm long, fan on low, 1 m away.Goal: most power from the same wind
- Test four flat blades facing straight into the wind.0.0 V, the rotor will not turn
- Twist the blades to a 20° pitch and measure the voltage across the resistor.1.2 V, so P = V² ÷ R ≈ 14 mW
- Try a 45° pitch.0.8 V, about 6 mW
- Keep the 20° pitch and test six blades instead of four.1.4 V, about 20 mW
Blades at a moderate pitch turned the most wind energy into electricity, and six blades raised the output to about 20 mW.
Why it works: Pitched blades turn the moving air's energy into rotation, and the coil spinning past the motor's magnets turns rotation into electrical energy, with some lost as heat and sound.
Common Mistakes with HS-PS3-3
Changing several things between tests
New pitch, new blade count and a closer fan in one trial
Try this: Change one design feature per test and keep the fan setting and distance fixed, so you know what caused the difference.
Judging by how fast it spins
“Ours spins fastest, so it makes the most power.”
Try this: Measure the electrical output across a load. A rotor that spins fast with no load can still deliver less power than a slower one.
Expecting all the energy to come out
“The fan uses 50 W, so our turbine should make 50 W.”
Try this: Only a small share of the wind hits the blades, and some is lost as heat and sound, so output stays far below input.
Where HS-PS3-3 Fits
Practice HS-PS3-3
Quick Check
- A device takes in 50 J and delivers 5 J of electrical energy. Where did the other 45 J go?
- Why test each design more than once?
- What is a constraint in a design challenge?