1001 Space Earth Nature History Human World Science and Technology Chemistry Materials Force and Energy Heat and Light Electricity and Magnetism Industry Machines Electronics and Computers Cars and Trucks Railways Ships Aircraft Fishing and Agriculture Undersea Exploration

Choose a Page:What happens when colours are mixed?How does the Sun produce light?What is light?How does a vacuum flask work?What is heat?What is colour?How does heat travel?What is temperature?How do thermometers work?What is the coldest possible tempe...How fast does light travel?*How do our eyes detect light?*How do glasses work? How do our eyes detect light? At the back of the eyeball is a layer of light-sensitive cells, called the retina. Photons (packets of energy) in lightwaves stimulate the cells of the retina and send messages to the brain, enabling us to see. The retina's rod-shaped cells work best in dim light, and its cone-shaped cells, which detect colour, in bright light.   Previous: Back Book: 1001 Section: Science and Technology Chapter: Heat and Light