Educational video for children to learn about pure substances and mixtures. Pure substances are composed of one single type of matter or element and their composition cannot be altered. Water and diamonds are pure substances. Mixtures are combinations of two or more pure substances. There are two types of mixtures: homogeneous and heterogeneous. In homogeneous mixtures it is impossible to pick out each component because they are not visible to the eye. In heterogeneous mixtures all components are clearly visible to the eye. Two examples of homogeneous mixtures are chocolate shakes and mayonnaise. What about heterogeneous mixtures? A tomato and lettuce salad would be an example. This science video for kids is an excellent resource for elementary school.