Our eyes can detect only a tiny part of the electromagnetic spectrum, called visible light. This means that there's a great deal happening around us that we're simply not aware of, unless we have instruments to detect it. Light waves are given off by anything that's hot enough to glow. This is how light bulbs work - an electric current heats the lamp filament to around 3,000 degrees, and it glows white-hot. The surface of the Sun is around 5,600 degrees, and it gives off a great deal of light. White light is actually made up of a whole range of colors, mixed together. We can see this if we pass white light through a glass prism - the violet light is bent ("refracted") more than the red, because it has a shorter wavelength and is slowed down more by the glass - and we see a rainbow of colors. This is called 'dispersion', and allows us to work out what stars are made of by looking at the mixture of wavelengths in the light. Too much light can damage the retina in your eye. This can happen when you look at something very bright, such as the Sun. Although the damage can heal, if it's too bad it'll be permanent. In the visible spectrum light is different colors because light has different wavelengths. Each color has their own own width and speed. How does the eye see light? Light rays enter the eye through the cornea, the clear front “window” of the eye. The cornea’s refractive power bends the light rays in such a way that they pass freely through the pupil the opening in the center of the iris through which light enters the eye. The iris works like a shutter in a camera. It has the ability to enlarge and shrink, depending on how much light is entering the eye. After passing through the iris, the light rays pass thru the eye’s natural crystalline lens. This clear, flexible structure works like the lens in a camera, shortening and lengthening its width in order to focus light rays properly. The back of the retina is packed with little receptors called rods and cones. These little receptors convert light into electrochemical signals...its a miracle we see at all isn't it? But this information is for another day, in biology.... Back to the spectrum: When light passes through our atmosphere, rain, clouds, moisture, trees, shadows and flares. We see colors. Sometimes the light breaks down into all the different wavelengths as it passes through different materials, like water drops, creating beautiful rainbows.
14 Comments
jenna
1/27/2017 10:51:38 pm
wow visible light is cool
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Emmalee
1/29/2017 07:19:29 pm
WOW. Light is so amazing
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Katelyn Ashton
1/29/2017 07:30:04 pm
Eyes are so freaky on the inside👁
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Savannah Ursic
1/29/2017 07:58:25 pm
Wow. this is really interesting, i also really liked the experiment with the tubes! It was really cool I hope we do more experiments like that. ;)
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Haley
1/29/2017 09:24:21 pm
wow that is interesting.
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Alivia murie
1/29/2017 10:56:39 pm
Light is so interesting. It makes me wonder about things we can't see
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Lord Voldemort
1/29/2017 10:58:36 pm
⚡
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Brady T
1/30/2017 07:02:02 am
Wow. It still amazes me that when light goes through a prism it breaks into different colors
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sydney
1/30/2017 07:13:14 am
I wish we could see infared
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Zaya
1/30/2017 07:18:27 am
Cool!!!
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Zaya
1/31/2017 07:36:45 am
Thanks for sharing that with us!😁
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Mrs. TaylorI love science! Everything about the world is interesting and never boring. I love to study plants, animals, insects, and people. My favorite subjects are my students who are the most unique organisms on the planet! Categories |