A diagram showing types of energy by color with labels. From left to right, colors are red, orange, yellow, green, blue, indigo, violet. Thermal IR and Infrared in a dark red section with label B. Ultraviolet and X-rays are in a dark violet section with label C. Visible light is between Infrared and Ultraviolet with label A on the red end and label D on the violet end. Long wavelengths begin on the left and become shorter on the right end. Use the drop-down menus to identify the type of energy each phrase describes.

The shortest wavelength of visible light

Energy that can be felt as heat but not seen

Short, invisible rays that can cause eye damage

Visible light with the longest wavelength