"The subject of this film is the particle model. It helps us to form an idea of the structure of substances and describe and identify various processes. Substances can be split up. For example, sugar can be found in different sizes: as sugar candy, as granulated sugar and as icing sugar. But that is not the smallest form of sugar. If sugar is dissolved in water, it practically becomes ""invisible"". We can no longer see it, but the sugar solution's sweet taste tells us that it is still there.
That's where the particle model helps us to understand what has happened to the sugar. When picturing the structure of substances, we assume that all substances are made up of the smallest, inseparable particles. Imagine these particles were small balls. We can neither see them with the naked eye nor under a microscope. A substance's particles are all identical. Different substances have different particles. This film visualizes the particle model using different experiments."