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This might come across as a very rudimentary question. My fundamentals of Optics are weak. In the optics chapter of my physics text book I saw diagrams each depicting an object on the left and a lens -- typically convex -- in the middle and an inverted image forming on the right side.

Let's say I want to perform this experiment, how can I do it?

I have always seen such lenses as parts of complex systems like cameras. Do I get such stand-alone lenses from the market off the shelf? And if I keep a candle on the left side, on what screen do I capture the image on the right side? A vertical plate, paper, or the like won't show an image. (Why is this so?)

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Buy some magnifying lens. A cheap one made from plastics will do. As object use a candle and to see the picture use a white paper as screen. – Georg Oct 8 '11 at 16:55
up vote 3 down vote accepted

Edmund Scientific sells very inexpensive optical components (probably items with slight manufacturing defects that commercial optics companies can't sell). For example, as of this writing they have an optical component grab bag available.

Then you need something to hold the components; some sort of modeling clay is fine for your purposes, most likely: it will make the edges of the lenses, prisms, etc. cloudy, but that doesn't really matter as long as you only handle and stick down the edges. You can use most anything, from upside-down cups to legos as a stand to hold up a lens at the same height as a candle, or you can cut a hole in a cardboard box as a lens holder, etc. etc..

Seeing objects on a screen is tricky because of all the other light in the room--only a very tiny bit goes through a lens and then is projected on a screen. So it's best to either use something very bright (candle, flashlight, LEDs, etc.) or do it in a dark room with only the object that you want to image illuminated (with a stand-lamp or somesuch).

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also have a look at for cheap optics... or go to a thrift store and pick up an old slide projector. – user2963 Oct 8 '11 at 20:38

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