Which is the odd one out?
Gold bar
Silver spoon
Bronze statue
The statue!
Gold and silver are both pure substances whereas
bronze is a mixture of copper and tin.
Metals are mixed together to change their
properties, including colour, strength and hardness.
Properties of mixtures
• Describe some of he properties that can
change when impurities are added.
• Give examples of how adding impurities to
water can be useful.
Why are these different?
Steel cutlery
Steel chain
The Cutlery is made from stainless steel which has different
elements added to help prevent rusting
Which of these metals is gold?
They both are! However, neither is pure gold. They both
have other metals added. Bizarrely, the ring on the left
contains twice the percentage of gold as the ring on the
right.
Everyday contexts
• How can the properties of metals be changed
by adding impuritites to pure metals? Give an
example of how this can be useful.
Everyday contexts
• Explain how does adding salt to the roads in
winter help motorists?
• Apart from changing the flavour, how might
adding salt to a pot of boiling water help a
chef?