Science Experiments -  Make A Model Elevator

Elevators of Lifts as they are popularly known are used to transport people up and down in tall buildings.
The lift cage or elevator car is lifted up and down by a spool that is turned by an electric motor. The elevator car is attached to the spindle by a  strong steel cable. Tracks attached to the sides of the elevator shaft ensure that the elevator car moves in a straight line. A counter weight balances the weight of the elevator car so that it becomes easy to pull it up. To move the elevator car up the motor rotates in a direction so that the cable gets wound around the spindle. To move the elevator down, the motor moves in such a direction that the cable gets unwound. Let us now try to make our own model elevator.
Material Required
A sheet of Plyboard or strong cardboard 
Six spindles (thread reels)
A small weight
A small cardboard box
Six Nails

1.Attach the spindles to the wooden board or cardboard using nails as shown in the figure
2.Take the small cardboard box and tie two strings to the top and one to the bottom. This is your elevator car.
3.Pass the bottom string from the box over spindles 3,4, 2, and 1 (make sure to loop the string at least twice over spindle 2) and tie it to the  first string on  the top of the box.
4.Pass the other string from the top of the box over reels 5 and 6 and attach it to a counterweight of about 100 gms.
5.Turn the spool 2 with your fingers. The elevator car should move up and down depending on the direction of your rotation of the spool.