HS-PS3-2: Motion Energy and Stored Energy
Also called NGSS HS-PS3-2 · Topic: Energy · Physical Science
The Official Wording
Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as a combination of energy associated with the motion of particles (objects) and energy associated with the relative positions of particles (objects).
Clarification statement: Examples of phenomena at the macroscopic scale could include the conversion of kinetic energy to thermal energy, the energy stored due to position of an object above the earth, and the energy stored between two electrically-charged plates. Examples of models could include diagrams, drawings, descriptions, and computer simulations.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-PS3-2 Means in Plain English
Students build models, such as energy bar charts, diagrams or simulations, showing that the energy of any visible object comes down to two kinds. Part is energy of motion, and part is energy stored by where things sit relative to each other.
The same idea reaches down to particles: thermal energy is the jiggling of atoms, and charged plates store energy by position. The standard sets no extra limits on models. It builds on MS-PS3-1 and MS-PS3-2 and leads to bond energy in HS-PS1-4.
HS-PS3-2 I Can Statements
- I can draw energy bar charts for a moving object.
- I can explain energy stored by an object's position.
- I can describe thermal energy as the motion of particles.
HS-PS3-2 Worked Example
A pendulum lab that turns a swing into numbers and bar charts.
Where does a pendulum's energy go between the top and the bottom of its swing?
Set It Up: A 200 g pendulum bob on a 1.0 m string, a meter stick, and a photogate at the lowest point.
- Pull the bob aside until it is 10 cm above its lowest point.Stored: 0.200 × 9.8 × 0.10 ≈ 0.196 J
- Release it and read its speed as it passes through the photogate.About 1.38 m/s
- Work out kinetic energy at the bottom.½ × 0.200 × 1.38² ≈ 0.190 J
- Draw energy bar charts at the top, halfway down, and the bottom.Stored bar shrinks as the motion bar grows
- Let it swing for two minutes and watch the height of each swing.Swings shrink as air and string warm slightly
The stored energy at the top nearly matched the kinetic energy at the bottom, with about 6 millijoules turned into heat.
Why it works: The bob's energy is a mix of motion and position above Earth, and the mix shifts during the swing while the total stays nearly fixed.
Common Mistakes with HS-PS3-2
Thinking energy vanishes when motion stops
“The pendulum stopped, so its energy is gone.”
Try this: The energy spread into the air and string as thermal energy, the random motion of particles, so it changed form without vanishing.
Giving stored energy to one object
“The book has potential energy all by itself.”
Try this: Stored energy belongs to a system, like the book and Earth together, because it depends on how far apart they are.
Bar charts with changing totals
Total bar taller at the bottom of the swing than at the top
Try this: Keep the total bar the same height in every chart unless energy enters or leaves, and show any heat as its own bar.
Where HS-PS3-2 Fits
Practice HS-PS3-2
Quick Check
- A pendulum bob is at the top of its swing. Which kind of energy is largest?
- Why does a block of wood get warm when you rub it?
- Where is the stored energy of a lifted book?