Page 159 - DK Children's Encyclopedia

Materials SEE ALSO

▸ ▸ Atoms p.34
▸ ▸ Buildings p.48
Materials are what all things in the world are made of. ▸ ▸ Electricity p.87
We describe them using their properties, which are how ▸ ▸ Gases p.117
they behave and what they do. They can be hard, bendy, ▸ ▸ Liquids p.148

waterproof, or magnetic. Materials will either float or ▸ ▸ Plastic p.195
sink, and electricity can pass through some of them. ▸ ▸ Solids p.234

Solubility Conducting heat
Solubility is how easily something Metals are good at conducting heat,
dissolves (mixes into) liquid. If you put which means when something hot
salt in water, the salt dissolves into it, touches them, the heat transfers into The rubber
so salt is soluble. Soluble materials them. Wood, plastic, and rubber are handle stays
can be solids, liquids, or gases. poor conductors of heat. Both cool, so we
can pick up
properties are useful in saucepans. the pan.

Sand is insoluble— This purple
it does not dissolve powder dissolves
in water. into the water.

The flame
causes the
metal pan
to heat up.

Conducting electricity Flammability
Copper conducts electricity, which means Flammability is how easily something catches fire
it allows electricity to flow through it. and burns. Dry wood is highly flammable, which
Plastic is an electrical insulator, which means it catches fire and burns easily, giving
doesn’t conduct electricity. Both are off heat.
useful in wire cables.

Dry wood
catches fire
Copper wire lets and burns
electricity travel easily.
through it.

Non-flammable
Plastic stops stones stop
electricity from the fire from
leaking out of spreading.
the cable.

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