GoalRemember natural and made materials, their properties, and how to choose and test the right material for a job.
New words
natural · found in nature, not made by peopleproperty · what a material is like, such as hard, soft, bendy or waterproofwaterproof · does not let water throughabsorbent · soaks up water
Explanation
Let us remember our materials. Natural materials come from nature, such as wood, wool, cotton and stone. Made materials are made by people from natural ones, such as plastic, glass, paper and brick. Every material has properties. A property tells us what a material is like. It may be hard or soft, flexible or rigid, strong or weak. It may be waterproof or absorbent, transparent or opaque. We choose a material because of its properties. A raincoat is waterproof, so the rain stays out. To test materials fairly, we change one thing and keep everything else the same.
Worked examples
A tent is made of waterproof fabric, so the campers inside stay dry in the rain. A tent made of paper would get soggy and fall down.
A playground ball is made of rubber, because rubber is flexible and bounces. A ball made of glass would smash.
Nodira wants to find the strongest sheet: writing paper, card or foil. She hangs the same coins on a strip of each. She changes the material and keeps the coins and the strip size the same. The strip that holds the most coins is the strongest.
Class activity
Material hunt (with an adult): walk round one room. Find six objects. For each one say what it is made of, one property, and why that material is a good choice. Then drop a little water on a sponge, a plastic lid and a piece of paper towel. Which soak up the water? Which keep it out? Dry up afterwards.
Practice
1
Write natural or made.
a natural; b made; c natural; d made.
2
Which material would you choose for a paddling pool: paper, plastic or wool? Why?
Plastic, because it is waterproof and keeps the water in.
3
Which of these materials is transparent?
B, the glass. You can see through it.
4
Yuki tests three cloths to see which soaks up most water. Name one thing she must keep the same.
For example: the amount of water, the size of the cloths, or the time they are left in the water.
