Science 7–10 · Year 10

Newton's first law: coin and card, glass on paper, and a passenger on a stopping trolley

Physical sciences — Waves and motion: motion and Newton's laws (NSW Stage 5 focus area)

PracticalLow risk

The idea

An object keeps its state of rest or steady motion unless a net force acts on it, so removing the surface beneath an object quickly lets it stay in place and stopping a trolley suddenly lets its passenger keep moving.

What you need

coin and a playing card on a plastic tumbler, 1 set
half-full plastic tumbler on a sheet of smooth paper, 1 set
dynamics trolley with a wooden peg or a small figure standing on it, 1
brick or heavy stop at the end of a runway, 1
stack of 5 draughts pieces and a ruler, 1 set

How to do it

Before each demonstration, predict what the object will do and write down the reason.
Balance the card on the tumbler with the coin on top. Flick the card sharply sideways and observe where the coin goes. Then push the card slowly and compare.
Stand the half-full tumbler on the paper near the bench edge. Pull the paper away with a fast horizontal jerk; then repeat with a slow pull.
Stand the figure on the trolley, push the trolley at steady speed into the fixed stop and watch the figure. Then start the trolley suddenly from rest with the figure standing on it.
Stack the draughts and strike the bottom piece sharply with the ruler; observe the rest of the stack.
For each case draw the forces on the object before, during and after the sudden change, and use the observations as evidence for Newton's first law in terms of the net force on the object.

What you should see

A fast flick lets the coin drop straight into the tumbler; a slow push carries it along with the card. A fast jerk does not topple the tumbler, which moves only slightly because of friction; a slow pull drags it off the edge. On impact the figure topples forward off the trolley; on a sudden start it topples backward. The struck draught flies out and the stack drops straight down. The learner knows it worked when each fast action lets the object stay where it was and each slow one carries it along.

What changes

This activity lists no variables to change, measure and keep the same.

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

A moving object needs a force to keep it moving.
The coin falls because the card pushes it down.
The passenger is thrown forward by a force when the trolley stops.

Safety card

Low riskLearners carry it out

Hazards

tumbler falling and breaking
flying draughts piece
trolley hitting hands at the stop

Controls

plastic tumblers only, the water-filled one over a tray
strike the draughts away from people
hands clear of the stop

Note

No hazardous chemicals or naked flames are used. Complete the school's risk assessment for the activity before the lesson; the NSW Department of Education Science safety and compliance page points to CSIS 1.7 (Risk assessment – a pre-requisite for risk control) for how to carry it out.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Science 7–10 Syllabus (2023)SC5-WAM-02 SC5-WS-02 SC5-WS-08
Australian Curriculum v9AC9S10U05AC9S10I01AC9S10I07

Sources

The pages the author read to write this activity.

All Concept Studio activities