The Visible Light Spectrum
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White light includes all primary colors (ROYGBV). Remember prisms from elementary school? This prism separates Red, Orange, Yellow, Green, Blue, and Violet from white light! I do want to point out, Violet does not mean purple! It is the "roses are red, violets are blue" color.
Violet is a flower. Click here to see some. https://en.wikipedia.org/wiki/Viola_(plant) |
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Picture source: http://blogs.nature.com/ofschemesandmemes/files/2015/02/Week-2-Blog-Dispersive-Prism.jpg
ROYGBV is just the visible light wavelengths!
Light penetration
You can see red light penetrate through your finger if you put it in front of a flashlight. You see red on the other side because most of the other colors were absorbed in your finger. Try this at home! Put your phone flashlight, or any white flashlight, on one side of your finger. Then look at what color makes it to the other side!
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www.researchgate.net/publication/316712743/figure/fig13/AS:668385360744448@1536366896067/a-Tissue-penetration-depth-of-light-with-different-wavelengths-NIR-light-penetrates.png
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https://images.theconversation.com/files/201297/original/file-20180109-83559-19kt3yi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip
Red light can be used to see inside your body.
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Something is not right with this finger!
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Got an X-ray and yep, something is there.
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All images are sourced from: http://www.eatonhand.com/img/img00087.htm
Let's shine red light on it. Yep, it's darker where something is sitting. That means there is not good blood flow there.
There is more deoxygenated blood in that spot.
There is more deoxygenated blood in that spot.
