The colours that make up sunlight are the colours of the rainbow: red, orange, yellow, green, blue, indigo, and violet. These colours are caused by the refraction of light as it passes through the Earth's atmosphere. The different colours of light are refracted at different angles, with violet light being refracted the most and red light being refracted the least. This is why we see a rainbow when we look at sunlight shining through water droplets or ice crystals.