system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does shampoo foam look white even if the shampoo was green, pink or whatever?
gpt
In the shampoos initial state, the little pieces that make the shampoo colored are so near together that only let light of the same color pass through. As you use the shampoo, tiny bubbles develop, that expand so much, that the colored pieces are seperated and every color of the light spectrum can pass through, which in the end join and make white light.