Science notes, unit 8

Absorption

Textbook Science Year 1 (DLP), pages 71–80

What this chapter covers

You can test objects and say if they absorb water or not (8.1.1)
You can sort objects into water absorbent and non-water absorbent groups (8.1.2)
You can compare which object absorbs more water and which absorbs less (8.1.3)
You can say why water absorbent objects are useful in our life (8.1.4)
You can say why non-water absorbent objects are useful in our life (8.1.5)
You can make a simple mini mop and say why you chose the string (8.1.6)

Some things soak up water. Some things do not. In this unit we find out which is which, and why it matters.

8.1Water absorbent objects and non-water absorbent objects

Absorbing water

Water absorbent objects take in water. Non-water absorbent objects do not take in water. The water stays on top as drops.

Syrup is spilled on a glass table, then Alia wipes it up and the table is dry — The glass table does not take in the syrup. The hand towel takes it in.

We can test an object. Put a few drops of coloured water on it and look.

Drops stay on top: the object is non-water absorbent.
No drops on top: the object is water absorbent.

Coloured water, a dropper, notepad, handkerchief, tissue paper, rubber, coins, paper clip, cotton balls and a plastic toy — Objects used in the test.

Keep the test fair. Use the same number of drops on each object.

After the drops go on a coin, the drops stay on top. Is a coin water absorbent?

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No. A coin is non-water absorbent.

Sorting objects

A kitchen with a straw, metal spoons, plastic plates, a glass, a door mat, a hand towel, kitchen paper and a mop — Objects in the kitchen.

Water absorbent	Non-water absorbent
Kitchen paper	Glass
Mop	Metal spoons
Door mat	Plastic plates
Hand towel	Straw

Soft things made of paper or cloth usually take in water. Hard, smooth things made of plastic, metal, glass or rubber do not.

Is a handkerchief water absorbent or non-water absorbent?

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Water absorbent.

Which absorbs more?

Some objects take in more water than others. In the test, strips of newspaper, kitchen paper and cloth stand in coloured water for 1 minute.

Strips of newspaper, kitchen paper and cloth are glued to a stick and dipped in coloured water — Strips of the same size are dipped in coloured water.

The kitchen paper absorbed the most water.
The newspaper absorbed the least water.

Example: a fair test

The three strips must be the same size and same thickness, and they stay in the water for the same time.

Which strip absorbed the most water?

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The kitchen paper.

8.2Why these objects are useful

Water absorbent objects

Object	What it does for us
Towel	Dries our body after a bath
Cotton ball	Cleans a wound
Cloth	Dries a jug
Handkerchief	Wipes away sweat
Mop	Wipes a wet floor

Non-water absorbent objects

A man with a plastic umbrella and rubber boots walks in the rain; an iron barrel collects rain water — Non-water absorbent objects keep us dry.

Object	What it does for us
Plastic umbrella	Keeps rain off us
Rubber boots	Keep our feet dry
Car glass windscreen	Keeps rain out of the car
Iron barrel	Collects and keeps rain water

Do not use a towel as a raincoat or a plastic sheet to dry your body. Pick the right object for the job.

Why do we wear rubber boots in the rain?

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Rubber does not absorb water, so our feet stay dry.

Mini mop

We can make a mini mop from string, thread, a pen and rubber bands. The string is used because it absorbs water. Cloth strips can also be used.

Pictures: Science Year 1 (DLP) textbook, pp. 72, 73, 75, 78.

Summary

	Water absorbent	Non-water absorbent
Water	Taken in	Stays on top
Examples	Tissue paper, towel, cotton ball	Plastic toy, rubber, coin, paper clip
Use	Dry and wipe	Keep us dry