Nothing speeds up, slows down or changes direction without a force. At Gravity Gorge, Year 5 scientists meet three forces that shape everyday life: gravity, which pulls things down; friction, which grips; and air and water resistance, which push back.
Apa yang akan dipelajari anak anda
- Know that gravity pulls objects towards the centre of the Earth
- Explain how friction slows moving things and helps us grip
- Describe air resistance and water resistance
- Explain why streamlined shapes move more easily
Gravity pulls, resistance pushes back
Gravity pulls a skydiver down. As she falls, air pushes up against her — that is air resistance. Open a parachute and the air has far more to push against, so she slows down.
Friction: nuisance and helper
Friction happens when surfaces rub. It slows a sliding box and wears out shoes — but without it we couldn’t walk, hold a pencil or stop a bicycle. Rough surfaces give more friction than smooth ones.
Contoh soalan
Berikut ialah beberapa soalan seperti dalam misi pertama. Bolehkah anda menjawabnya?
1. Which force slows a sliding box?
- Friction
- Gravity
- Light
- Magnetism
Tunjuk jawapan
Jawapan: Friction. Friction acts between the box and the floor.
2. Which surface gives the most friction?
- Polished glass
- Smooth metal
- Rough carpet
- Wet ice
Tunjuk jawapan
Jawapan: Rough carpet. Rough surfaces grip more than smooth ones.
3. Which is harder to walk on?
- An icy path
- A dry pavement
Tunjuk jawapan
Jawapan: An icy path. Ice is smooth, so there is very little friction.
Tip untuk orang dewasa
- Drop a flat sheet of paper and a scrunched one together — which lands first, and why?
- Slide a toy car down a ramp covered with carpet, then with foil.
- Look at the shapes of fish, boats and planes and talk about streamlining.