Grade 4 Science And Technology Machines – Levers Notes
Science & Technology — Machines
Subtopic: Levers (for age 9)
A lever is a simple machine. It helps us move or lift things using less force. A lever has three important parts:
- Fulcrum — the point that the lever pivots on (like a seesaw’s middle).
- Load — the thing you want to move or lift (the weight).
- Effort — the push or pull you use to move the load.
How a lever helps:
If the handle (where you push) is long, you can move a heavy load with a smaller push. The position of the fulcrum decides how easy it is.
Three classes of levers
1st Class Lever — fulcrum in the middle
Seesaw (playground)
Fulcrum is between effort and load. Example: children on a see-saw.
2nd Class Lever — load in the middle
Wheelbarrow (farming)
Load sits between fulcrum and effort. Easy to lift heavy loads.
3rd Class Lever — effort in the middle
Tweezers or fishing rod
Effort is between fulcrum and load. Good for speed and control (not for lifting very heavy things).
Simple class activity (use at home or school)
- Find a pencil (the plank), an eraser (the fulcrum) and a small toy (the load).
- Put the pencil on the eraser and try to lift the toy by pushing down on one end of the pencil.
- Move the eraser nearer the toy and try again. Is it easier or harder?
Observation tip:
When the fulcrum is closer to the load, less effort is needed to lift it. If the fulcrum is in the middle, both sides balance.
Quick quiz (write answers)
- 1. Name the three parts of a lever.
- 2. Which class of lever is a wheelbarrow?
- 3. Give one example of a 1st class lever found at school.
Fun fact: Farmers in Kenya love wheelbarrows because they make moving soil and seed much easier — that is a 2nd class lever in action!