| Light 9-10 &11, 2009 period 2
What is light? Light is a form of energy the whole planet needs Light travels through space Lights up a room on a sunny day Helps us see in the dark Sunlight is white light Light sound and electricity are all forms of energy Light comes in several different forms Light is a flow of tiny particles The colors mixed up in sunlight often become separated Light bulbs contain a length of coil called a filament made of metal called tungsten Where does light come from? Heat � hot or chemical reaction (firefly/lightning bug) Light is produced when an excited electron moves out of its normal Path then returns. Energy loss + light All light is created in atoms Light travels more slowly in transparent materials Most of the light that comes from the sun and lamps are invisible Whey you stand outdoors in the sunlight it cannot pass through your body Light rays bend when ever they change speed How do we use light? We use light to grow food Solar panels produce electricity Light for indoors to see Office building shopping malls When your pupils get big it�s because it is trying to catch more light so you can see. When your pupil is small its be cause it�s trying to get rid of some light Humans once depended on candles made of animal fat and oil lamps burning vegetable oil Light travels more slowly through glass and water than it does though air Gamma rays are used t o keep goes forces free of germs What do waves have to do with light? Light travels in waves Longest wavelengths we see are red Shortest wavelengths we see are violet Wavelength= distance from top of one to top of the other Light travels at @186,200 miles per second Electromagnetic spectrum = wavelengths traveling from the sun Microwaves are generated by a tube called a magnetron Fans can spin microwaves Waves change speed and direction as they enter a new medium at an angle All electromagnetic waves travel at the same speed 186,200 miles per second that�s more than 463,000 more faster than the Electromagnetic waves are transverse waves and made up of continually changing electric and magnetic fields Light travels more slowly in transparent materials such as glass water or air than it does in a vacuum Why do rainbows sometimes appear? Water splits light like a prism Prism � any object that refracts light passing through it (white light) Refract = bends A rainbow is the visible spectrum The sharpest rainbows is a primary rainbow ROY G BIV |
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