Where can energy go when kinetic energy decreases?
Submit: An evidence record, explanation and revision.
Related lesson: Kinetic and Potential Energy
This is a teacher-led extension beyond the short lesson. The task supplies a performance opportunity; completion alone does not certify mastery, full NGSS coverage or state alignment.
Teacher review guideBuild the idea
A moving object has kinetic energy. When it slows, energy can transfer to other objects or become thermal energy through interactions. “Energy was used up” fails to account for where it went. Observable deformation, sound or warming can support an account, though a tiny temperature change may be below a classroom thermometer’s resolution.
Science / engineering practice
Argument from evidenceCore idea
Changing kinetic energy accompanies energy transferCrosscutting concept
Energy and matterEvidence and model inputs
Observation plan: roll a large ball slowly along a cleared surface into a soft barrier. Compare motion before and after contact and record barrier deformation or sound. No numerical kinetic-energy calculation is needed. A model may include thermal transfer that the apparatus cannot directly resolve; label that inference.
Keep actual observations, published findings and invented model cases labeled separately. If a source or required equipment is unavailable, pause that part with a teacher; do not invent results.
Materials and preparation
Large ball, soft barrier, safe floor space and drawing sheet.
Grade-level scope
Qualitative energy arguments only; no kinetic-energy formulas required.
Do the work
- Draw a system boundary containing the ball, barrier and nearby floor.
- Observe at least three safe low-speed trials and record changes in motion and the barrier.
- Draw energy-transfer arrows for contact and distinguish observations from inferred thermal changes.
- Argue that decreasing ball kinetic energy accompanies transfer or transformation elsewhere.
- Challenge the claim that stopping destroys energy; revise any arrow with no physical interaction.
Learner worksheet
Write on paper or type here and print. Entries stay in this page’s memory and are lost when you leave or reload; they are not saved or submitted.
Check your reasoning
- Does a stopped ball have the same kinetic energy as before?
- Does that imply energy disappeared?
- Is inaudible sound evidence of no transfer?
- Can you claim measured warming without a temperature measurement?
Teacher review guide
Review the actual deliverable and discuss the reasoning. For each criterion, use 0 when evidence is absent or fundamentally incorrect, 1 when partly supported with a material error or omission, and 2 when accurate, supported and complete for the stated task. Maximum 8 points is a task score, not a proficiency certification. Give feedback and allow revision.
- Records observable motion and contact changes.
- Defines a useful system boundary.
- Argues for energy transfer using evidence and qualified inferences.
- Revises an energy-disappearance explanation.
Answer guidance for the reasoning checks
Does a stopped ball have the same kinetic energy as before?
No; its kinetic energy is lower.
Does that imply energy disappeared?
No. Account for transfers and other forms.
Is inaudible sound evidence of no transfer?
No. Other pathways can occur.
Can you claim measured warming without a temperature measurement?
No. Label a thermal account as an inference when it was not measured.
Access, support and extension
Offer read-aloud support, labeled diagrams, larger print or an oral/recorded explanation while preserving the scientific reasoning. A partner or teacher can handle physical manipulation while the learner plans, records and interprets. Use a teacher-provided measured dataset only when its provenance and limitations are explicit; it does not replace conducting an investigation when that is the assessed practice. For greater independence, remove prompts and ask learners to compare a second explanation or test another justified revision.
Sources and standard reference
- Official NGSS MS-PS3-5 performance expectation — inspect the practice, core idea, crosscutting concept and assessment boundary.
Instructional text and hypothetical cases are original. Linked source readings supply published evidence where specified. Teachers should judge fit with their course and state requirements.