- Ask learners what shape the wheels of the toy car are (round/circle).
- Ask them why they think the wheels need to be round.
If they were square, it would be bumpy when you push it.
If they were oval it wouldn’t turn smoothly:
- Show learners the picture of Egyptians pulling a huge stone block. You will find this picture on pg 53 of THUNDERBOLT KIDS.
- Ask learners why they put the blocks on round logs.
To move it more easily; to work together; because they can’t lift the block.
- Show learners the following simple demonstration:
- – Place a stone on a piece of cardboard.
- – Place the cardboard on a number of pencils.
- – Now push the stone gently forward.
- – Ask learners what they notice about the demonstration.
The pencils moved forward and in a circular movement when you pushed the stone; the pencils acted like wheels.
- Show Presentation 1, explaining as you go through it.
- Explain to learners that when we have to move a real heavy load, we have to use a great deal of force to push it, because of:
Friction: A force that resists the motion of the object on the ground.
Gravitational force: Force that pulls the object to the ground.
This problem is solved through the uses of wheels and axles.
- Show Video Clip 1 (12.46 minutes). This video explains the functioning of simple machines (wheels and axles).