LIGHT The atmosphere causes light to be displayed in breathtaking ways such as during a sunset iStockphoto Thinkstock 12
THE FUNDAMENTALS OF LIGHT Scientists have learned that all these forms of energy and many other kinds of energy such as radio waves microwaves and gamma rays have the same structure They all consist of electri cal and magnetic fields that work together in a special way to form electromagnetic radiation SoURCES OF LIGHT Unlike many other ani mals humans depend primarily on sight to learn about the world around them During the day early peoples could see by the light that came from the Sun but night brought darkness and danger One of the most impor tant steps people have taken to control their 13
LIGHT A rainbow forms when the Sun's rays strike raindrops falling from distant rain clouds A ray of white sunlight is actually composed of all the colors of the spectrum Inside the raindrops the ray is sepa rated into the individual colors that make it up violet blue green yellow orange and red Jan Mika Shutterstock com environment occurred when they learned to conquer the dark by controlling fire a source of light Torches candles and oil lamps are all sources of light They depend on a chemical reaction burning to release the energy we see as light Plants and animals that glow in the dark glowworms fireflies and some mushrooms change the chemical 14
THE FUNDAMENTALS OF LIGHT THE ELECTROMAGNETIC SPECTRUM An X ray revealing the bones of buman hands xpixel Shutterstock com Electromagnetic EM radiation is one of three general categories of radiation the others being mechanical radiation and parti cle radiation EM radiation is sometimes referred to as light or radiant energy It can travel through a vacuum as easily as it can 15
