It looks like they are trying to teach you some of the basics of waves, as well as a little bit of techniques on making graphs from a few data points to determine linear relationships, etc. ## \\ ## When working with light waves from a given source, the frequency of a monochromatic (single color) source is fixed, but when it travels through different media, (e.g. air, water, glass), the speed (of light) will change, depending on the index of refraction of the material, so that the wavelength changes. What you did in this experiment should help give you a good introduction that topic, when you encounter it.