Forces as arrows, balanced forces, what unbalanced forces change, and the difference between mass and weight. Concept tutorials with a live force diagram that can also run the motion.
Each lesson works two ways. Students can work through the online tutorial at their own pace (it checks their answers and saves their progress in their browser), or you can teach it to the whole class from the slides, then send students into the tutorial for the Modify and Make steps.
Every lesson guide has plain-language notes, the answers to every check, a solution for every task, and slides and a worksheet for Waypoints Prepare. These guide pages are not linked from student pages, but they are not secret either: keep printed Teacher editions for answers you do not want students to find.
Representing forces, what balanced forces do (and don't) mean, what unbalanced forces change, and gravity (AC9S7U04).
A force is a push or a pull. It has a size (in newtons, N) and a direction, so we draw it as an arrow: longer arrow, bigger force. A force diagram shows every force on one object, each named (weight, support, friction, push, air resistance…).
Node 5 brings the unit together, so it is a class task, not a tutorial. The checkpoint: students can say which of two objects speeds up more under the same force, and read the pattern in force data.
Investigation (about 30 minutes). Pull a trolley along the bench with a stretched rubber band (one band, then two side by side) and time it over 1 m from rest; then add a mass to the trolley and repeat. Keep the surface, distance and starting point the same. Groups record the time for each run and say what changed.
Predict first. "The same rubber band pulls an empty trolley and a loaded one. Which speeds up more?" (The empty one: same force, less mass, bigger change in motion.)
Data to read (example figures, not real measurements): time to roll 1 m from rest.
| Trolley | One band | Two bands |
|---|---|---|
| Empty (0.5 kg) | 1.4 s | 1.0 s |
| Loaded (1.0 kg) | 2.0 s | 1.4 s |
Questions: Which pull changed the motion most quickly, and how can you tell? What did adding mass do? Which two runs are the fairest test of mass alone? (The same column.) Why do two bands on the loaded trolley match one band on the empty one?
Success criteria (from the progression): states the relationship in words (a bigger unbalanced force gives a bigger change in motion; a bigger mass gives a smaller change for the same force); predicts which object speeds up more under the same force; identifies the pattern in data. Keep it qualitative: F = ma waits for Year 10.
Watch for: "heavier objects need a force to keep moving" (from node 2), and mixing up mass and weight (node 4) when students explain why the loaded trolley is slower.
On screen: the short tutorial Same push, different mass covers node 5 (the qualitative relationship and the data pattern); the investigation above still comes first.
Optional ideas if you run a practical for this unit: pick one, adapt it to your equipment, or use your own.
Safety and ethics: keep feet clear of falling masses, and drop from standing height, not from chairs or desks.