Question: Why is grass green?

Pete Etchells answered on 26 Apr 2012:

Hi debbiehoran! That’s a really good question – grass, like all plants, needs to photosynthesise in order to feed itself. That means that it needs to take in carbon dioxide and water, and use energy for the sun to create food. The most important substance that is used in this process is called chlorophyll, which is the substance that allows light energy to be absorbed. Grass is green, because chlorophyll reflects the green part of the light spectrum, and absorbs the rest. As to why it reflects green instead of, say, red, we don’t really know – it could have quite easily evolved that way! Biologists think that most plants evolved from an ancient form of sea algae which itself was green, and that’s probably the reason why.

Hope that answers your question!