MS-PS3-2: Potential Energy and Distance
Also called NGSS MS-PS3-2 · Topic: Energy · Physical Science
The Official Wording
Develop a model to describe that when the arrangement of objects interacting at a distance changes, different amounts of potential energy are stored in the system.
Clarification statement: Emphasis is on relative amounts of potential energy, not on calculations of potential energy. Examples of objects within systems interacting at varying distances could include: the Earth and either a roller coaster cart at varying positions on a hill or objects at varying heights on shelves, changing the direction/orientation of a magnet, and a balloon with static electrical charge being brought closer to a classmate’s hair. Examples of models could include representations, diagrams, pictures, and written descriptions of systems.
Assessment boundary: Assessment is limited to two objects and electric, magnetic, and gravitational interactions.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What MS-PS3-2 Means in Plain English
Middle schoolers build models showing that when two objects that push or pull without touching move closer together or farther apart, the energy stored between them changes. They compare a book on a high shelf with one on a low shelf, or two magnets held close versus far.
Students compare more and less stored energy without calculating it, and they work with two objects at a time linked by gravity, magnetism or static electricity. This builds on kinetic energy (MS-PS3-1) and on forces that act across a distance (MS-PS2-5), and it leads to field models in HS-PS3-5.
MS-PS3-2 I Can Statements
- I can explain why a higher book stores more energy.
- I can show how moving two magnets changes their stored energy.
- I can draw a model comparing more and less potential energy.
MS-PS3-2 Worked Example
A magnet boat test a class can run with a tub of water and two bar magnets.
Does pushing two repelling magnets closer together store more energy?
Set It Up: Two bar magnets, a foam tray boat with one magnet taped on top, a tub of water, a ruler and masking tape marks along the tub.
- Tape one magnet to the tub wall just above the water, north end facing in.Fixed magnet at one end
- Turn the boat so its magnet's north end faces the fixed magnet, hold it 6 cm away and let go.Boat drifts about 5 cm
- Hold the boat 3 cm away, pushing against the repelling force, and let go.Boat drifts about 20 cm
- Hold it 1 cm away and let go.Boat drifts about 45 cm
- Run each spacing three times and record the drift distances in a table.Closer start, longer drift every time
The closer the magnets started, the farther the boat drifted, so more energy was stored when they were pushed together.
Why it works: Pushing two repelling magnets together stores energy in the magnetic interaction between them, and that stored energy becomes motion when the boat is released.
Common Mistakes with MS-PS3-2
Putting the energy inside one object
“The book has the energy.”
Try this: Potential energy belongs to the pair, like the book and Earth together. Change the distance between them and the stored energy changes.
Assuming closer always means more energy
“Magnets touching always store the most energy.”
Try this: For objects that attract, energy is stored by pulling them apart. For objects that repel, it is stored by pushing them together.
Confusing stored energy with motion
A model that labels a book resting on a high shelf as “moving energy”
Try this: A resting book has no kinetic energy. Its energy is stored between it and Earth because of its height.
Where MS-PS3-2 Fits
Practice MS-PS3-2
Quick Check
- A backpack sits on the floor, then on a desk. When is more energy stored?
- Two magnets attract. Do you store more energy by pulling them apart or by letting them snap together?
- Why must a potential energy model show two objects, not one?