The Magic Fountain
You will need:
- One transparent acrylic tube (Length 90 centimeters, diameter 2 centimeters)
- One plastic tub
Step by step instructions:
- Fill up 80% of the plastic tub with water.
- Stick the acrylic tube into the tube and use the palm of your hand to cover the tube while leaving a little sliver of space. This will allow the water to enter the tub. (As shown in Diagram A)
- Use your palm to fully cover the tube and raise the tube slightly. (As shown in Diagram B) The water level will rise as well. (As shown in Diagram C)
- Repeat steps 2 & 3 until water comes out from the top of the tube. (As shown in Diagram D~E)
※Be careful! Acrylic tube can only operate in the bucket, do not pick it up and play around.
How it works
If the tube is lifted when its top is covered (as shown in diagram B), the pressure within the tube is less than the atmospheric pressure (resulting in a semi-vacuum effect). This means that most of the water will stay within the tube (as shown in diagram C). If the tube is lowered at the same time as its top is uncovered (as shown in diagram D),though, some of the water inside the tube will be lost as a consequence of its weight.
However, since the pressure inside the tube is the same as the pressure outside the tube, not all of the water will be lost, and some of the water will remain within the tube (as shown in diagram E). By repeating the process, the level of water in the tube will soon rise and appear as a fountain.
＊Resource come from: NTCU Science Game Lab.