A scientist named Henry Cavendish proved that water is not an element by splitting it into its elements, hydrogen and oxygen, using electrolysis. Electrolysis is the process of splitting a compound by passing electricity through it. While most substances expand when heated and contract when cooled, water is unusual in that it expands when cooled to just above freezing at 4°C before freezing solid at 0°C.

1. Science- water

2. Electrolysis Of Water:
The chemical name for water is hydrogen
oxide, which obviously means it is a
compound.
A Scientist called Henry Cavendish proved
that water isn't an element. By splitting
water into it's elements hydrogen and
oxygen. He did this by passing electricity
through water using a Hoffmann
voltmeter.

3. Electrolysis:
Electrolysis is the splitting up of a
compound by passing electricity
through it.
Water = Hydrogen + oxygen

4. Expansion Of Water:
As a general rule all substances expand when
heated and contract when cooled. Water
behaves as expected until it is cooled to 4ºC.
On further cooling it actually expands!

5. Properties Of Water:

Water freezes at 0ºC. Ice will melt to form water
at 0ºC. Thus 0ºC is the freezing point of water
and the melting point of ice.

Water is an excellent solvent. A huge variety of
substances dissolves in it.

Water is colourless, odourless liquid.

The boiling point of water is 100ºC

6. The Water treatment:
1. Screening: The water passes through screens or
meshes which trap any floating material.
2. Settling: water is stored in large reservoirs where heavy
particles settle at the bottom.
3. Filtration: The water passes up through thick beds of
sand. Any remaining insoluble particles are removed
from the water.
4. Chlorination: Chlorine is now added to kill any bacteria
that may be present.
5. Fluoridation: fluoridation is added to help prevent tooth
decay.

7. The Water treatment:
1. Screening: The water passes through screens or
meshes which trap any floating material.
2. Settling: water is stored in large reservoirs where heavy
particles settle at the bottom.
3. Filtration: The water passes up through thick beds of
sand. Any remaining insoluble particles are removed
from the water.
4. Chlorination: Chlorine is now added to kill any bacteria
that may be present.
5. Fluoridation: fluoridation is added to help prevent tooth
decay.