South Dakota Science MS-PS2-1

ScienceGrades 6–8Physical Science

The Standard

Design a solution to a problem involving the motion of two colliding objects that illustrates Newton’s Third Law. (SEP: 6; DCI: PS2.A, ETS1.B; CCC: Systems) Alignment may include MS-ETS1-1

South Dakota Science Standards (2024) · Motion and Stability: Forces and Interactions

Teacher's field guide

What This Standard Means

What Students Need to Do: Students design a bumper for two colliding toy cars, then test whether it protects both cars. They explain how each car pushes on the other during the crash.
What Mastery Looks Like: A student sets a test goal, such as keeping paper passengers on both cars, and improves a bumper after a trial. They show equal, opposite force arrows on the cars, even if one car changes speed more.
Common Misconceptions: Students may think the heavier or faster car pushes harder, or that a stopped car does not push back. They may also think equal forces mean both cars change speed by the same amount.
How to Assess It: Exit ticket: Two toy cars collide and both paper passengers fall off. Sketch an index-card bumper, describe one test, and draw the force arrows on both cars during contact.

Lesson moves

Ways to Teach It

Build folded index-card bumpers for two toy cars, then roll the cars together and check whether paper passengers stay on.
Ask: If a heavy car hits a light car, which pushes harder during contact? Have students explain their answer in two sentences.
Give pairs three collision sketches and force-arrow cards; have them match the cards and fix any unequal arrows.
Show a photo of two bumper cars colliding and ask students where they would add padding to reduce jolts to both riders.

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