Up next in How to Do Fun Tech & Science Projects (52 videos)
School science fair coming up? Don't worry: We've got step-by-step instructions to dozens of science projects in this Howcast video series, including how to build an erupting volcano, how to make glow-in-the-dark art, how to make a weather barometer, how to make disappearing ink, how to make 3-D glasses, and how to make a marshmallow gun.
You Will Need
- Room with 1 window
- 3 or more 28x22-in. sheets black poster board
- Utility knife
- Duct tape
- White sheet (optional)
- Blanket (optional)
- Camera with exposure settings (optional)
Find a room
Find a room that has a window with a decent view. Look for a blank wall opposite the window, since that's where the picture will be projected. If it's not blank, hang a white sheet on the wall.
Create the lens
Unscrew the ring from the top of the flashlight and remove the lens. Place the ring in the middle of the sheet of poster board, and cut a hole around it. Then, tape the ring to the cardboard with duct tape. This will be the lens for the camera obscura.
Prepare the room
Tape the remaining poster board over the window, overlapping if necessary. Leave an area uncovered in the middle of the window for the lens.
Add the lens
Tape the lens backing to the window with duct tape. The window should now be completely covered, and aside from the lens hole, there should be no light passing through.
Darken the room
Turn off all lights in the room and close the door so that the only light entering the room is from the camera lens. After a few minutes, your eyes will adjust to the dark, and an image should appear on the wall opposite the window.
View the image
You should now see an upside-down image of the outside world projected onto the wall. Why? Since light rays travel in a straight line, they hit the objects outside, pass through the small opening of the lens, and transmit an upside-down image of the objects on the opposite wall. This is the same method cameras use to capture images.
Capture your creation
Unless you want to cover your entire wall in photographic paper, you'll need a way to capture what you see. Grab a camera with an adjustable exposure setting and set the exposure to around 30 seconds, which is ideal for low-light photographs. Take a moment to marvel at your contraption; it's not every day that you get to walk inside a camera!