102
Almost everything around us is made from some sort of material.
Each has different properties, such as strength or flexibility,
which makes it useful for making particular products. Some
materials, such as wool or stone, grow or occur naturally.
Synthetic materials are manufactured. Composite materials
combine the properties of two or more materials to
achieve the best possible product.Materials
(^1) SILK
This natural fibre is made from the
cocoon of the silkworm. Each cocoon
may produce 3 km (2 miles) of silk.
Silk can be woven into an extremely
fine fabric, and is prized for its
texture and its shiny appearance.
(^2) CONCRETE
Concrete is made by mixing sand,
gravel, cement, and water. It is
a liquid when freshly made, so
it can be poured into a mould,
where it sets to form an extremely
hard and durable material.
Plastics can be
moulded into
almost any
shape or size
(^4) WOOL
This natural material comes from the
fleece of sheep. The structure of its
fibres means wool has a tendency to
shrink, so it is often mixed with synthetic
fibres to make easy-care fabrics.
(^3) KEVLAR
A light, flexible, synthetic material, Kevlar
is used for protective clothing, such as
bulletproof vests. Kevlar molecules are
arranged in long chains with strong
bonds between them, which makes
Kevlar five times stronger than steel.
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2
4
8
7
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5
3
Most metals are
malleable and
can be bent
without breaking
Concrete is the main
material used for
modern buildings
Kevlar is used
to reinforce
helmets, so that
they are light
but very strong
102_103_Materials.indd 102 03/01/19 12:10 PM