How does shape affect speed? In this experiment we are going to find an easy answer to the above question.
Things Required:
Card table
2 books of equal thickness
1 large roll of masking tape
2 jar lids, the same size
Marble
Masking table
Helper
Directions:
Tilt the card table by placing one book under two of the legs. Place the lid tops together and tape their edges to form a disc. Ask your helper to hold the disc made from the lids at the top of the incline while you hold the marble and tape roll in line with the disc. Release all three objects at once.
This Is What Happens:
The marble rolls fastest, with the lid disc coming in second, and the tape roll last.
Science Behind It:
The rolling speed is related to the distribution of weight around the centre of gravity of the object (the point where the weight appears to be located). The closer the weight is to the centre of gravity, the faster the object can rotate. The centre of gravity of all the objects in this experiment is at their geometric centre, but each has a different weight distribution. The weight of hollow tape roll is located farthest away from the centre of gravity. It has the slowest rotation speed. The weight of marble is closest to its centre of gravity, resulting in it having the fastest rotating speed.
