Water Fountain 1 (Using Difference in Water Levels)

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Watch the video on YouTube.

What kind of experiment is this?

Experimental procedure and explanation:

• Cover one end of a tube with a piece of vinyl and use a rubber band to hold the vinyl in place. Use a toothpick to make a small hole in the vinyl.
• Fill the tube with water; then, change the heights of the water on the left and right. The difference (height A) in the heights of the water levels on the left and right acts as the energy source that causes the water to spout. The difference in heights is proportional to the potential energy of the water.
• The height (height B) of the water fountain created by the spouting water is invariably lower than height A. The difference between height A and height B corresponds to energy lost through factors such as the viscosity of the water. This energy loss can be reduced by increasing the diameter of the tube.
• In the second experiment, water in a bucket is used to create a water fountain in the same manner. The difference in the height between the surface of the water in the bucket and the exit (height C) acts as the energy source that causes the water to spout. The difference between height C and height D of the water fountain corresponds to the energy that is lost.
• These two water fountains use the energy of the water height (potential energy).
  The water height corresponds to water pressure calculated by the following equation.
  

  	(Water Pressure) = (Water Density) × (Gravitational Acceleration） × (Water Height)
  Ex)	For example, the density of water is 1 g/cm3 (= 1000 kg/m3) and the gravitational acceleration is 9.8 m/s2. If height A is 30 cm (= 0.30 m), the water pressure becomes 1000 × 9.8 × 0.30 = 2940 Pa. Pa (read Pascal) is the unit of pressure. When calculating, ensure that conversion to kg and m (SI units) is done.

[Keywords]	water depth, pressure, potential energy
[Related items]	Water Height and Energy
[Reference]	“The Wonders of Flow,” [Remark 1] Japan Society of Mechanical Engineering, Kodansha Blue Backs, pp.38-41 and 98-101 “Illustrated Fluid Dynamics Trivia,” by Ryozo Ishiwata, Natume Publishing, pp.18-19 and 192-193