An introduction to separating mixtures. Salt is soluble in water, when salt is added to water most of it dissolves to make a solution. When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation. The water can also be recovered as well as the salt if the water vapour is trapped and cooled to condense the water vapour back into a liquid. This process is called distillation.
This clip is useful as a way of introducing the children to scientific vocabulary including soluble, insoluble, evaporation, filtration and distillation through the use of visual explanations. The visual explanations provide experiments that could be carried out within the classroom.