# Pinhole Camera

## Students’ Learning Outcomes                                                                                               Explain the scientific principle that works in a pinhole camera.

#### Information for Teachers

 Pin-hole Camera
A pinhole camera, also known as camera Obscura, or “dark chamber”, is a simple optical imaging device in the shape of a closed box or chamber. In one of its sides is a small hole which, via the rectilinear propagation of light, creates an image of the outside space on the opposite side of the box.

A pinhole camera doesn’t have any lens but there is a very small hole (slit) in it. It is a dark box, which has a small hole on one side. Light from an object passes from this small hole and form its inverted image on the opposite side of the hole. Smaller the hole, sharper the image will be.

Activity 1        Pinhole camera works on the principle that light travels in a straight line.

Show a pinhole camera to the students. Tell them that it is a box, which has a small hole (slit) on one side. Inside the box, in front of the slit there is a translucent screen. On the other side of the box there is the peeping hole.
Direct the pin-hole toward an object and call the students one by one to look at the translucent screen from the peeping hole. Ask questions:
1.            Is the image inverted or upright?
2.            Is the image coloured?
3.            What happens to the size of image when the pinhole is larger in size?
Explain the principle of pinhole camera.

A pinhole camera works on a simple principle. Imagine you are inside a large, dark, room-sized box containing a pinhole. Imagine that outside the room is a friend with a flashlight, and he is shining the flashlight at different angles through the pinhole. When you look at the wall opposite the pinhole, what you will see is a small dot created by the flashlight’s beam shining through the pinhole. The small dot will move as your friend moves his flashlight. The smaller the pinhole (within limits), the smaller and sharper the point of light that the flashlight creates.