Where is the centre of gravity of an object? This is what we are going to reach for in this experiment.
Things Required:
Paper hole punch
Push tack
Washer
String, 12 in. (30 cm)
Scissors
Manila folder
Ruler
Tack board
Directions:
Cut one side of the manila folder into an irregular shape. Punch four randomly spaced holes in the edge of the paper with the paper hole punch. Tie one end of the 12-inch (30 cm) string to the washer. Attach the free end of the string to the push tack. Stick the tack through one of the holes in the paper and into the tack board.
Allow the paper and string to swing freely. Use the ruler to mark a line on the paper next to the string. Move the tack to the other holes and mark the position of the hanging string each time. Do this for all four holes. Place the paper on the end of your index finger. Your finger is to be below the point where the lines cross.
This Is What Happens:
The paper balances on your finger.
Science Behind It:
The earth’s gravitational force-gravity-pulls downward on everything. The centre of gravity is the place on an object that acts as if all the gravitational force pulling on the object is pulling from that spot. The centre of gravity point of the paper is that point where the four lines cross. The paper can be balanced at this spot because all the weight of the paper is evenly spaced around its centre of gravity. Hold your finger under that point and observe the balance.
