Digital Interactive Content

Water and Changes of State

The water cycle

Water’s ability to change in state from liquid to gas and back to liquid is responsible for the water cycle, which in turn gives us a continuous supply of fresh water to sustain life on Earth.

The need for water conservation

Although 70% of the Earth is made up of water, fresh water that is readily available makes up but a fraction of the water on Earth.

Evaporation and condensation in a solar still

The salt content in seawater is too high and cannot be drunk to sustain life. Devices such as solar stills make use of the processes of evaporation and condensation to separate water from salt in seawater to produce fresh water that is potable!

Harvesting water from air

Maximising the condensation of water vapour in the surrounding air to form water droplets is essential to meet the water demands of people living in hot and dry environments such as deserts.