Supergiant stars may contain multiple energy sources within shells. Hydrogen in the outer shell burns into the heavier element Helium giving off heat energy and light. The Helium in the inner shell burns into Carbon and Oxygen. The star is getting hotter towards the core. Ultimately the star may contain heavy metals like Iron and Nickle at the core.
Prism When sunlight passes through a glass of water to land on a wall, we see a rainbow on the wall. This would not happen unless white light were a mixture of all of the colours of the visible spectrum. Isaac Newton was the first person to demonstrate this. Newton passed sunlight through a glass prism to separate the colours into a rainbow spectrum. He then passed sunlight through a second glass prism and combined the two rainbows. The combination produced white light. This proved conclusively that white light is a mixture of colours, or a mixture of light of different frequencies. The combination of every color in the visible spectrum produces a light that is colourless, or white.
