Pinhole Camera

Principle: When light passes through this hole, an inverted image of outside objects is projected on the opposite side where it is recorded on a photographic film.
Applications:In surveillance (close observation) and spy cameras
Items Required to make:A shoe box / Corrugated Box of any reasonable size
Aluminum kitchen foil
Greaseproof paper
Black tape / Or normal tape and black colored paper
A sharp needle for pinhole
Fun Facts to know:
Clock Radios were fitted with hidden pinhole color camera in which the camera and transmitter in such away that they are invisible to the human eye. Obviously that’s the actual purpose of using them. They can be used as spy cameras and in surveillance system

Shoot A Reel

Principle:
When you pull the fixed reel, elastic energy is stored in the stretched rubber band. When you release it, this elastic energy gets converted to kinetic energy, and the reel moves upwards.
Applications:Catapults, Trebuchets, Canons, etc.

Items Required to make:
2 sticks (cycle spokes)
2 long rubber bands
2 empty thread reels
1 stick, shorter length
String & Cycle value tube
Fun Facts to know:
Can you Improvise the toy so that it has a trigger (same like a gun)
Make the same toy using some other sticks.
Can you make the bullet travel a distance of 50 feet (upto 4th floor)?