Investigate how forces change motion with and without contact

Learning goal: Investigate changes in motion caused by forces, compare the effects of different push strengths under similar conditions and recognize examples of forces acting without direct contact. Use a toy car, a safe barrier and an adult-selected magnet with a suitable steel object. Adults manage magnets and keep them away from mouths and sensitive equipment.

A force is a push or pull. It can start an object's motion, make it move faster or slower, change its direction or help stop it. Describe the motion before and after the action. “I touched the car” names an action but does not specify whether the car sped up, slowed or turned.

To compare push sizes, use the same toy on the same level surface from the same starting place. Give it a gentle push and observe. Reset and use a somewhat stronger push in the same direction. A larger push can produce a greater change in motion, but the outcome also depends on the object and conditions. Changing the toy, slope and surface at once would make the cause of a difference unclear.

Record an actual measured quantity or a clear observation. Distance traveled before stopping is affected by the surface as well as the initial motion. It is not automatically a direct measure of the force or of speed. A useful first investigation can report that the toy traveled farther under otherwise similar conditions, then discuss what additional tools would be needed to measure speed precisely.

Some forces act at a distance. Bring a suitable magnet close to a small steel object on a clear surface without touching it. If the object moves toward the magnet, the gap provides evidence that direct contact was not required for this interaction. Do not generalize that every metal is attracted to a magnet. Use only the adult-selected sample and report what was tested.

Gravity is another force that acts without contact between an object and Earth's surface. When a safely held small object is released, it begins to fall toward the ground before touching it. The floor can stop the object through contact later; that stopping contact is different from the gravitational pull during the fall.

The illustration places contact and noncontact examples side by side. In the car panel, a hand touches and pushes the toy. In the magnet panel, a visible gap separates the magnet and steel object. Arrows show the depicted force directions, not measured force sizes. The two arrows have different lengths, but the lengths are layout choices and do not measure or compare force strengths.

Use cautious explanations when an object does not move. An opposing force or barrier may prevent visible motion even while a push is applied. The absence of movement does not prove the absence of every force. Compare a car against a barrier with the same car free to roll, using gentle actions.

Worked example 1: Name a change. A rolling car meets a gentle opposing hand and slows to rest. The contact force changes its motion. A push does not always mean the car becomes faster; the direction and situation matter.

Worked example 2: Read the gap. A magnet attracts the selected steel object across a gap. Because the magnet has not touched it, this is evidence of an interaction without direct contact. The picture's gap matters more than the arrow's decorative length.

Worked example 3: Distinguish falling and stopping. Gravity pulls a released object toward Earth while it is above the floor. Contact with the floor happens later and changes the object's motion again. Do not say the floor touched the object all the way down.

Guided investigation: Observe start, slow, stop and turn examples with the same toy. Compare two gentle push strengths while keeping the setup similar. Then observe an adult's magnet demonstration and a safe release-and-fall example, identifying whether direct contact occurs in the interaction being discussed.

Independent tasks: Describe a before-and-after motion change, identify a condition to keep alike in the push comparison and distinguish contact from noncontact examples. Explain why a stationary object against a barrier can still be experiencing a push.

Feedback: If every arrow is read as a measured amount, revisit its legend. If the learner calls all metal magnetic, ask which samples were actually tested. Credit a precise description of the particular force and observed change rather than a slogan about motion.