225
Brittleness
Some materials, such as glass, are
very brittle and will break when
pushed out of shape. Safety glass is
designed to crack rather than break.
Properties of matter
Safety
glass
Yes, a diamond is the hardest mineral of all. It will scratch quartz.
A smooth flow
Some liquids flow more
easily than others. It depends
on their “stickiness”, or viscosity.
Hot lava from a volcano flows
slowly because it is sticky.
1
Talc
Hardness
A scientist called Friedrich Mohs created a
scale of ten minerals to compare how hard they
are. Many materials are graded on this scale.
Compressibility
Gases can be
squashed, or
compressed, by
squeezing more
into the same
space. This is what
happens when you
pump up a tyre.
2
Gypsum
3
Calcite
4
Fluorite
5
Apatite
6
Feldspar
7
Quartz
8
Topaz
9
Corundum
10
Diamond
Gas can be compressed
because its particles are far
apart. A bicycle pump pushes
the particles closer together.
Diamond is
the hardest
mineral.
H
a
n
d
s
o
n
Foot pump
Gas particles
Softest
mineral
Collect some
different pebbles
and put them in order of
hardness. A pebble is harder
than another if it scratches it.
This is how Mohs worked
out his scale.
