| Light
What is light? Light is a form of energy the whole planet needs Travels through space Lights up a room on a sunny day Helps us see in the dark Light sound and electricity are all forms of energy It takes light 8 minutes and 20 seconds to travel from the sun to the earth Light travels from the sun 93 million miles The sun looks big but actually it�s actually a fairly small star Shadows is not an object � it is receiving less light than the area around it An object or material that lets through most of the light such as a window is called transparent Where does light come from ? Heat/hot or chemical reaction (firefly /lightning bug) Light is produces when an excited electron moves out of its normal path then returns � energy loss = light All light created in atoms It takes 0.1 second for light to travel from New York to London Most of the light that comes from the sun and from lamps is invisible 2000 years ago scientist discovered invisible light You can make a light bulb glow by using a battery and two wires The colors you see depend on the light that enters your eyes How do we use light? We use light to grow food Solar panels produce electricity Light for indoors to see Office buildings shopping malls When there is little light the pupil will get bigger to help you see Streetlights shine to help us find our way What do waves have to do with light? Wavelengths make up electromagnetic spectrum All light travels in waves / 186, 200 miles per second Longest wavelengths we see look red Shortest wavelengths we see look violet Light waves measured in wavelengths Top of one wave to the other is a wavelength Colors of rainbow � only light you can see When a wave hits an obstacle or passes from one substance or another it can change in speed direction or shape before the change the wave is called an incident wave In 1801 Wilhelm Ritter investigated the light of energy of different parts of the spectrum and Discovered ultraviolet light Electromagnetic filed changes in strength and direction all the time Why do rainbows sometimes appear? Sunlight refracts off of raindrops Weather must be just right Raindrops act like a prism Refract = bend Prism = any object that refracts light passing through it Sunlight = white light=visible spectrum=ROY G. BIV Compact discs diffract whit light making its colors visible |
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