Grade 6 Science And Technology Force And Energy – Force Notes

A force is a push or a pull that can make things start moving, stop moving, change speed, change direction, or change shape. We write force as F. The SI unit of force is the newton (N).

• Pushing a wheelbarrow (push)
• Pulling a jerrycan from the water point (pull)
• Using a hoe (jembe) to dig — force changes the soil shape
• Kicking a ball during football — changes its motion

• Contact forces — forces that need touch: push, pull, friction.
• Non-contact forces — act without touch: gravity, magnetic force.

• Gravity (weight): pulls everything toward the ground. Your weight is a force. (Unit: N)
• Friction: a force that opposes motion between two touching surfaces (e.g., shoes on classroom floor).
• Magnetic force: attracts or repels metals like iron without touching (e.g., magnets).
• Applied force: when you push or pull an object (e.g., push a table).

• Make an object start moving (push a ball).
• Make a moving object stop (apply brakes).
• Change the direction of an object (kick a ball to the side).
• Change the shape of an object (squeezing a sponge).

When two or more forces on an object cancel out, they are balanced and the object does not change motion. If they do not cancel, they are unbalanced and the object will start moving or speed up/slow down.

A spring balance measures force in newtons. You hang an object and read how many newtons show on the scale. Try this simple classroom activity:

1. Hang a known mass (e.g., a 1 kg weight) from the spring balance.
2. Read the value — the weight is about 10 N (on Earth) because gravity pulls with about 10 N per kilogram.
3. Try different masses and write the readings.

If you push harder (more force), an object speeds up more. Scientists use a rule F = m × a, which means:

Force equals mass × acceleration — just remember: more force or less mass = easier to make it move faster.

1. Push an empty wheelbarrow and then push when it is full. Which needs more force?
2. Pull and push a drawer with one hand and then two hands. How does force change motion?
3. Do a tug-of-war. Which side wins — the side with greater force?

1. Give two examples of contact forces and two of non-contact forces.
2. What unit do we use for force?
3. What happens when forces acting on an object are balanced?
4. Why is it harder to push a heavy box than a light box?