World Book Trivia Quiz For Kids---light-australia

Explanation
The violet waves are the shortest waves we can see, and red waves are the longest.

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Waves too short to be seen are called ultraviolet rays. They cause sunburn and suntan. Waves too long to be seen are called infrared rays. They cause the warming we feel in sunlight.

Explanation
One kind of light bulb is an incandescent bulb. It passes electricity through a metal wire called a filament. The filament heats up and glows. It sits inside a glass bulb. Fluorescent bulbs pass electricity through special gases in a glass tube. The gas gives off energy. The energy is invisible. But it makes a coating on the glass glow brightly.

Explanation
Electric power is measured in units called watts. For example, it takes 100 watts of electric power to operate a 100-watt light bulb. The world's power plants produce billions of watts at any given time.

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Gas lamps were used in the 1800's. The gas was piped into the lamp. It burned as it rushed out of a small opening and mixed with the air. Today, gas lamps are sometimes used by campers. Such lamps provide light in places with no electric power.

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A prism is a thick, three-sided piece of glass or a kind of rock called quartz. It can change the direction of light. It can also break light up into the colours of the rainbow.

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Rainbows are curved bands of coloured light that appear in the sky. We see rainbows when the sun shines on raindrops. Sometimes both ends of the rainbow seem to touch the ground.

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A light-year is the distance that light travels in one year. The light-year is used by scientists called astronomers. They use the light-year to describe the huge distances between stars, galaxies, and other objects in space.

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Scientists measure the wavelength, brightness, and speed of light. The speed of light in empty space is always the same. In space, light travels at 186,282 miles (299,792 kilometers) per second.

Explanation
Some light, such as sunlight, comes from nature. Other light comes from things people make, such as lamps. But all light comes from atoms , tiny particles of matter that make up everything in the universe.