Ejection out due to the weight of the weight

Let's take a look!

What type of experiment is this?

Experimental procedure and explanation:

• We apply the "Piston and Cylinder" experiment to make the water flow in an upward direction.
• We cut the top of the plastic cup to exactly fit the size of the measuring cylinder. Next, we punch a hole in the bottom, thread a straw through it, and glue it in place. We then cut the straw that comes out from the bottom to ensure that it is short. Further, we cut the top slightly lower than the rim of the cup.
• In this case, we used a brass disk as a weight, with four nuts in between to pass a gap between it and the bottom of the cup (water flows between the nuts).
• Then, we gently place the weight in a measuring cylinder filled with water. In doing so, water gushes out of the straw. This concludes the experiment.
• The increase in internal water pressure is obtained by (the magnitude of the gravitational force of the weight) divided by (the area) (which is then weakened by the frictional force between the cylinder and the piston). Therefore, the heavier the weight, the higher it rises.
• It can be seen that if the cylinder is made narrower, a weight of the same weight will be ejected higher.
• [Tips for making it] The cut circle of the plastic cup should not be too large or too small. It is important to cut it carefully to ensure that it fits the diameter of the cylinder. Further, flow resistance occurs as it passes through the straw. However, the energy loss can be reduced by making the straw wider and shorter. However, when as the straw diameter is increased, its effect will be short-lived.
• This experimental video was produced with the support of JSPS Grant-in-Aid for Scientific Research 18K03956.

[Keywords]	Pressure, outflow velocity
[Related items]	Pistons and cylinders, The Height of Water and Its Energy, Water Fountain 2 (Using Pressure)
[Reference]	Ryozo Ishiwata and Mitsumasa Nemoto, "The Wonder of Flow", Kodansha Blue Backs, P34-37, P98-101 Ryozo Ishiwata, "Illustrated Fluid Dynamics Trivia", Natsume Publishing, P14-15, P102-193

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