Topic: Handing Water
Material: glass, paper, pin, water
1. Make some holes on the paper
2. Fill the glass up of water
3. Hole the paper over the glass
4. Tip the glass over while still holding the paper
5. Remove the hand after a few seconds
Questions and explanation:
1. Why will the paper stay at the same place after ...view middle of the document...
When the glass is full of air at the same pressure, you have the amount of push downwards as upwards. They balance each other. With the glass full of water, when the water starts to move downwards, there is nothing to take its place. This produces an area of extremely low pressure. The higher on the outside is then plenty strong enough to keep the paper in place.
2. Why does not the water leak from the holes?
Water does not lea from the holes, because the surface tension of the water, the water on the paper surface of the film-forming water, the water will not leak.
Difficulty of the experiment:
At the first time of the experiment, we made the holes too big, and the paper fell very soon.
When tip the glass over, it’s not easy to use the paper to cover the top the glass, some water will leak from the edge of the glass.
The construction paper is too thin and gets wet very soon. And the paper will fall down.
We have to tip the glass over very quickly; otherwise, the paper will fall immediately.