Two metal forks, Modeling clay, Flat toothpick, A drinking glass
1. Make a ball of clay about the size of a large marble.
2. Insert the tip of one of the forks into the clay ball. The stronger your clay, the better your experiment will work.
3. Insert the second fork at about a 45-degree angle from the first fork.
4. Insert the pointed end of the toothpick in the clay between the forks.
5. Place the end of the toothpick on the edge of the glass.
6.Move it further over the glass until the forks balance. If the forks do not balance, decrease the angle between them.
7. Make any other adjustments until the forks balance.
The angle of the forks spreads their weight so that there is one place on the toothpick where all of the weight seems to be located. This spot is called the center of gravity. If you suspend an object from any point, let it go and allow it to come to rest, the center of gravity will lie along a vertical line that passes through the point of suspension. Unless you've been very careful in balancing the object, the center of gravity will generally lie below the suspension point.
- 적당한 각도를 찾으면 포크는 떨어지지 않고 매달려 있게 되는데 그 점을 우리는 중력의 중심이라 부른다. 중력의 중심은 포크가 매달리는 점을 지나가는 수직선을 따라 있을 것이다.