How we see color
There are three types of color receptors in your eye: red, green and blue. But how do we see the amazing kaleidoscope of other colors that make up our world? Colm Kelleher explains how humans can see everything from auburn to aquamarine.

Is light a particle or a wave?
Can we accurately describe light as exclusively a wave or just a particle? Are the two mutually exclusive? In this third part of his series on light and color, Colm Kelleher discusses wave-particle duality and its relationship to how we see light and, therefore, color.

What is color?
Have you ever wondered what color is? In this first installment of a series on light, Colm Kelleher describes the physics behind colors-- why the colors we see are related to the period of motion and the frequency of waves.