Testing Water: Presence and Purity

In this video, the presenter demonstrates two tests for water - one that tests for the presence of water and another that tests for the purity of water. The first test involves heating hydrated copper sulfate crystals which turn white when the water is driven off. When the crystals are exposed to water again, they turn blue, indicating the presence of water. The second test involves measuring the boiling point of the water sample. The presenter explains that while the presence of water can be useful, it can also be detrimental in certain situations, and testing for water purity is important in determining its suitability for various uses.