Today is rung 4 of 5 on this topic
Forces, motion and Newton's laws
Can do: Applies the three laws to real situations and draws a force diagram.
Why it matters
Newton's first law contradicts everyday intuition, and until that's confronted directly, physics stays confusing.
What it looks like when it's wobbly
Believes a constant force is needed for constant speed, and that a moving object always has a force in its direction of travel.
⏱️ Two-minute check
"A spacecraft coasting with engines off — what force keeps it moving?"
Solid looks like: None. It keeps moving because nothing is stopping it.
The full activity for this topic · 25 minutes
Friction Is the Liar
- 1Roll a car across carpet, then wood, then a polished surface, measuring the distance.
- 2Extrapolate: what if friction were zero? That's the first law.
- 3Test the second law: same push, different masses, and note the acceleration difference.
- 4Find three action-reaction pairs in the room — walking, sitting, jumping.
- 5Draw force diagrams for a book on a table and a car accelerating.
If it's too hard
The friction ramp and the first law only.
If it's too easy
Calculate acceleration from F = ma and predict a distance.
Say this
"Nothing is pushing it forwards. So why is it still moving? What's actually slowing it down?"