A Different Type of LensThe lenses we will be talking about here are not the lenses in your eyes, but rather the types of lenses that correct your vision and lenses that are in objects that some of us use everyday, like telescopes.
There are two types of lenses that help correct vision: plus lenses and minus lenses. Here are the proper definitions for both types of lenses from the science.howstuffworks website: Plus lens: a lens that is thickest at the center; moves the focal point forward Minus lens: a lens that is thinnest at the center; moves the focal point backwards. Plus LensesHere are the characteristics of plus lenses:
Minus LensesHere are the characteristics of minus lenses:
Games!Play this game to see images taken by the Hubble Telescope. You will be timed to see how many images you can find.
Click here to do activities like Make Your Own Hand Held Hubble, see Giant Telescopes of Tomorrow, watch a Space Sky Show and more! |
More Experiments for your eyesMake pictures from light using a lens. Click here!
TelescopesHave you ever wondered how telescopes work? The general way they work is that they use a lens to gather a lot of light and then they "focus it by bending or reflection it to form images of faint stars and other far-away objects.
To read a more detailed account of how telescopes work click here.
To connect the dots...If you are Near-sighted:
1. Your cornea is too curved and/or your eye is too long. 2. You cannot see far away objects clearly 3. You need a minus lens because the image is focusing in front of the retina and this lens will help bring the focus farther, so it lands on the retina. If you are far-sighted: 1. Your cornea is too flat and/or your eye is too short 2. You cannot see near objects clearly 3. You need a plus lens because the image is focusing in front of the retina and this lens will help make the focus shorter, so it lands on the retina. Videos!Check out the video below to see exactly how lenses work.
Watch this next video to see how camera lenses are made.
What's to comeIn the next few pages things that can be used to correct vision will be talked about. So continue reading!
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