Chapter 1 WHAT IS LIGHT Have you ever tried to run away from your shadow Have you ever made faces in front of a mirror Without light you couldn’t play these games Playing games with light can be fun But we also need light Why is light important 4
Light is a form of energy Light lets us see the world around us Light also makes heat The sun gives off a lot of light and heat Sunlight Light from the sun makes life on Earth possible Sunlight carries energy to plants and animals Sunlight also carries heat to Earth All water on our planet would freeze without the warmth from sunlight Most of our light energy comes from the sun 5
Other Light Sources Fire makes light and heat too A fire can be used to heat things or to make an area bright Light energy from lightbulbs brightens buildings and neighborhoods Some lasers use light energy to cut things The red light on this remote controls the television 6
Atoms and Photons Light is very important But where does it come from Light comes from tiny particles called atoms Atoms are so small that billions of them would fit on the period at the end of this sentence Like you atoms can get excited An atom becomes excited when it gets extra energy The particles inside an excited atom move faster If the atom is excited enough a small burst of light energy shoots out This small burst of light energy is called a photon Everything around you is made of atoms Air water plants furniture and even your body are made of atoms 7
