An experiment to demonstrate how minerals dissolve in water and a look at which minerals and metals are found in different types of water. Water is poured into a flask and we see what happens when it starts to boil. As the water heats up it starts to evaporate. The gas travels out of the flask and into a cold tube. The water vapour condenses and drops out as a liquid. The scientist is then able to look at the minerals contained in the sample of water and explains how minerals are dissolved in water as it flows through the ground.

This clip is from:
Science Clips, Changing State
First broadcast:
11 October 2007

A useful way of reinforcing soluble and insoluble materials, as well as explaining how to separate mixtures. Before watching the clip, children could be presented with three or four beakers of liquid (eg mineral water, tap water, lemonade, water with soil mixed in). Pose the question: "Is this liquid safe to drink?" Take answers from the children, highlighting the danger of drinking unknown solutions. By challenging the children to test whether there is anything dissolved or mixed in the water, their knowledge of filtering and evaporation can be taught, tested or assessed. Once the pupils have carried out the physical processes, discuss the residues and identify the original liquid. The clip can be used as a plenary to show how minerals are extracted from water by evaporation and are left behind as a residue.