Things We Use Every Day
Primary 1 · Science and Elementary Technology
Things We Use Every Day
Lesson 2 of 3
12 min
Let's begin
Umutoni closes her eyes. Her friend puts two things in her hands: a stone and a towel.
"Which is which?" asks her friend. Umutoni does not need her eyes at all. "This one is the stone. It is hard and cold. This one is the towel. It is soft."
Her hands told her. Today you will learn the words your hands already know.
Press a stone with your thumb. Nothing happens. It does not squash. The stone is hard.
Now press a pillow. It goes in. Take your thumb away and it comes back. The pillow is soft.
Hard means it does not squash when you press it.
Soft means it squashes when you press it.
Hard things: a stone, a nail, a metal pot, a wooden desk, a baked clay pot, a glass window.
Soft things: a towel, your uniform, a pillow, cotton wool, wet clay before it is baked.
Careful! Wet clay is soft. You can squeeze it in your fist. But bake it in a hot fire and the same clay becomes hard. One material, two feelings, before the fire and after the fire.
Rub your hand slowly along a brick wall. It scratches. It has tiny bumps. That wall is rough.
Now rub your hand along a window. Your hand slides. There are no bumps at all. The glass is smooth.
Rough means bumpy, and it scratches your hand.
Smooth means flat, and your hand slides easily.
Rough things: a brick, a stone, the bark of a tree, sandpaper, a dusty road.
Smooth things: glass, a plastic bottle, a metal spoon, a polished desk, a banana peel.
Take a plastic ruler in two hands. Push. It curves! Let go, and it jumps straight again. The ruler is bendy.
Now try to bend a nail with your fingers. It will not move at all. The nail is stiff.
Bendy things: cloth, a plastic ruler, rubber, a thin stick, paper.
Stiff things: a nail, a metal pot, a wooden door, a clay pot, glass.
Cloth is the most bendy of all. That is why you can fold a bedsheet small and put it in a box. Try folding a window!
Pour a little water on a towel. The water disappears into the cloth. The towel gets heavy and wet. Cloth soaks up water.
Now pour water into a plastic basin. The water just sits there. Not one drop goes through. Plastic holds water.
Soaks up water: cloth, paper, a sponge.
Holds water: plastic, metal, glass, a baked clay pot.
Now you know why nobody carries water home in a paper bag.
Gatete sorts four things into two piles: hard or soft.
Two piles. Two of each. He did not guess. He pressed.
Tip
Do not guess with your eyes. Use your hands.
Press it → hard or soft?
Rub it → rough or smooth?
Bend it → bendy or stiff?
Wet it → does it soak the water up, or hold it in?
Do the test in your head first, then tap Show answer to check.
You press a nail hard with your thumb. Nothing happens. Is a nail hard or soft?
Answer: hard. Hard things do not squash when you press them.
Is a brick wall rough or smooth?
Answer: rough. It is bumpy and it scratches your hand.
Uwase folds her bedsheet into a small square. Is cloth bendy or stiff?
Answer: bendy. Cloth bends any way you like. That is why you can fold it.
Habimana pours water into a cloth bag and into a plastic bucket. Which one holds the water?
Answer: the plastic bucket. Cloth soaks up water and lets it through. Plastic holds it in.
Sort these into the hard pile and the soft pile: a stone, a towel, a glass window, your school shirt.
Answer: hard → the stone and the glass window. Soft → the towel and your school shirt.
Note
What you learned today:
Quick check
Match each test to what it tells you.
Tap one on the left, then its partner on the right.
