Activity Title: D.I.Y Smart Phone Projector
Breathe new life into that old cardboard box lying in the recycle bin by turning it into a cool projector!
What do I need?
For this activity, you will need the following items:
1. a small cardboard box (about 8 x 6 x 12)
2. a magnifying glass or camera lens
3. kitchen scissors, exacto knife, or small serrated knife
5. a smart phone
How do we do it?
1. Place the magnifying glass on the front of the box and trace it.
2. Using the scissors, cut a hole in the box that is slightly smaller than the traced circle.
3. Make a stand for the phone by folding a spare piece of cardboard and secure it with a piece of tape. Slide the phone stand into the box, under the cardboard flap in the bottom of the box.
4. Next, tape the magnifying glass inside the box so that the lens is aligned with the hole in the box.
5. Add the smart phone on the stand and voila, your projector is ready!
6. Find a blank wall, turn off the lights and enjoy your projector
Note: you may need to move the projector to adjust the image if it is blurry.
What is the science behind it?
The lens of the magnifying glass is convex, meaning its sides bend outwards. This allows it to catch, bend, and focus all the light from inside the box and project it onto the wall. You may have noticed the image was upside down and you had to flip the phone to get the picture to show properly. The human eye has a lens similar to the magnifying glass attached to the projector. What the eye sees comes through the eye’s lens upside down but the brain learns to flip the image right side up. The magnifying lens flips the image through refracting the light from the phone’s screen just like your eye flips the light from the world.
Without a “brain” to flip the image in this activity, we had to set the phone in the box upside-down.