Materials and Making Things
Primary 2 · Science and Elementary Technology
Materials and Making Things
Lesson 2 of 3
13 min
Let's begin
It is evening at Mutesi's home. Her mother is cutting potatoes with a knife. Her father is tapping a nail into the door with a hammer. Her big brother pushes a wheelbarrow full of bricks up the path — all by himself.
Nobody is doing these jobs with bare hands. Every single one of them is holding a helper. Today you will meet those helpers.
Try this in your head. Take a plank of wood and try to cut it in two with your fingers. Pull, pull, pull. Nothing happens. Your fingers are soft. The wood is hard.
Now pick up a saw. Push and pull, push and pull. The little sharp teeth bite into the wood, and soon the plank is in two pieces.
So here is the rule. A tool is a thing you hold, that does a job your hands alone cannot do.
| Tool | Its job |
|---|---|
| Knife | Cuts food |
| Hammer | Hits nails into wood |
| Saw | Cuts wood |
| Hoe | Digs the soil |
| Needle | Sews torn cloth |
| Scissors | Cut paper and cloth |
| Broom | Sweeps the floor |
| Bucket | Carries water |
Worked example
Umutoni's school skirt is torn at the hem. Which tool?
First ask: what is the job? The job is to sew the cloth together.
Then ask: which tool does that job? Look down the table. Sews torn cloth — that is the needle. So Umutoni takes a needle and thread.
Not a saw. A saw cuts. A saw would turn her skirt into two skirts!
A machine is bigger than a tool. A machine has parts that move, and it makes a heavy job easy.
Worked example
Habimana must move twenty bricks to the back of the house.
Carrying them in his arms? Two bricks at a time, ten trips, and his back hurts.
Now he uses a wheelbarrow. He loads all twenty bricks in. The wheel turns, so the bricks roll along instead of being lifted. He pushes them all in one trip. The machine did not make the bricks lighter — it made the job easier.
Machines at home:
Look at these: an electric iron, a fridge, a light bulb, a phone charger, a television.
None of them will do anything until you plug them in. They need electricity.
But a wheelbarrow needs no plug. A bicycle needs no plug. They are pushed by your own muscles. That is the difference.
Worked example
The beans are cooked. Uwase's mother must lift the pot off the charcoal stove.
She does not grab it with bare hands — the metal handle would burn her in one second. She folds a thick dry cloth, takes hold of the handle through it, and lifts.
Why dry? The heat turns the water in a wet cloth into hot steam. Steam burns your hand very fast. So a wet cloth is worse than no cloth at all.
Fire rules:
Worked example
Ishimwe has just washed the plates. His hands are dripping. He wants to plug in the radio.
He must not. Water carries electricity straight into your body. So he dries his hands well on a towel, and then he asks an adult to put the plug in.
Electricity rules:
Did you notice? With electricity the answer is always the same three words: do not touch.
Warning
Before your hand touches anything, ask three quick questions. Is it sharp? Is it hot? Does it use electricity? If any answer is yes, stop and call an adult. That is not being a baby. That is being clever.
Tip
To pick a tool, always name the job first. "I must cut cloth." Then the tool walks straight into your hand — scissors. If you pick the tool first, you end up hammering a potato.
Answer out loud. Then look below.
What you learned today
Quick check
Match each tool to its job.
Tap one on the left, then its partner on the right.
