Rob from What Is It? provided me a follow up to the Magnifying Glass Optical Illusion post. Rob included the below picture and this explanation.
If you put a magnifying glass a few inches from a wall that is opposite a window, you will see the outside view projected upside down on the wall. But if you put a lens on the window and cover the rest of the window with opaque material, the lens will project the outside view over the entire opposite wall, of course you must have the proper size lens for the room.
This is a picture that Rob took after conducting his lens experiment. You can see the view outside his room is projected on the wall. If you would like to do this for yourself follow the instructions on this site.
3 comments:
oh wow *stares*
The below comments previously archived on haloscan.com
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When I did the lens on the window experiment, I just did it temporarily by covering the windows with black posterboard to block all light, cut a hole for the lens and then taped it on the posterboard. I got a blank lens from an optician, if it's not the right focal length you can have them grind it a little for you. So it's not necessary to do all of the work shown on the web site unless you want to use it for a long time.
Rob
Anonymous | 05.05.05 - 3:31 pm
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Thanks for providing us with this update.
Walt
Walt | Homepage | 05.05.05 - 7:03 pm
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Very interesting little physics here. Really worth reading.
Quentin | Homepage | 05.08.05 - 9:42 am
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Great site! And it seems you're from MN?! Zoinks! I surfed here via http://dzeni.blogspot.com/
Tracy | Homepage | 05.10.05 - 12:51 am
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Tracy,
Thanks for stopping by. I just added your site and Dzeni's site to my sidebar. Been meaning to do that for a while now. Just got around to it today.
I currently hail from North Carolina.
Walt | Homepage | 05.10.05 - 4:29 am
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Tracy,
I meant to say that about two hours before you left your comment I added your site my sidebar.
Small world isn't it?
Walt | Homepage | 05.10.05 - 4:31 am
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You know...I was thinking what a great little activity this would be for my kids and I. And then I read all that goes into it and it started to sound like work. But thanks to Robs comment, I still might try it.
Thanks Rob.
Danny Kaye | Homepage | 05.23.05 - 4:12 pm
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I'm certainly no expert on optics, but it seems to me that it would be quite trivial to throw in another lens to invert the image so it is right side up. Anyone know why this isn't done?
Curtis | 08.18.05 - 10:31 am
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this is actually known as a camera obscura. or a pinhole camera. you can do the same thing with a small box with a hole and some light sensitive material...you dont even need the lens, just a pinhole.
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