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Optics Question

  1. Apr 20, 2012 #1


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    Hi guys, I have an optics question. I am running an activity for kids to simulate being inside a camera. So I am in a dark room, and I have a small hole in one of the doors which allows light in. An image comes in through the hole, and a magnifying glass can be used to focus this image, which creates a brilliant effect and is really impressive. My only problem is that the light shines diagonally in through the hole and lands on the side of the wall which isnt really ideal. The aim is to project the image onto a wall/sheet onto the back. Does anyone have any idea how I can change the direction of the image projection?
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  3. Apr 20, 2012 #2

    Andy Resnick

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    google "camera obscura". A colleague did this for my class recently- he simply put a large roll of white paper at the back of the room, but didn't use any lens at all. It was an incredible demo.

    Why does the light not exit the hole symmetrically? Is the hole too close to the wall? Or am I not understanding something...
  4. Apr 21, 2012 #3


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    I have a door at the front of the room, and am trying to project the image outside to the back of the room. However, just inside the door there is a small side wall. The light seems to be shining here (in full colour), and I can use a magnifying glass to focus on objects from the outside. Ideally, I would be able to change the direction of the light entering the room and project it onto a white sheet at the back of the room. I don't know how to achieve this however. Any ideas much appreciated!

    Another thing I should mention is that the hole is not in the exact center of the door. Does it need to be in the centre for the light to shine straight through to the back??

    Its a great effect, when people walk by you can see them, and you can see any movement. I'd love to be able to achieve this, it really impresses the kids.
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