The Height of Water and Its Energy

Let's take a look!

Watch the video on YouTube.

What kind of experiment is this?

Experimental procedure and explanation:

• Poke some holes at different points down the side of a plastic bottle and compare the momentum of water (flow velocity) coming out of these holes. (The holes could be made with push pins, but be careful not to hurt yourself.)
• You can see that water from holes closer to the bottom have larger momenta (flow velocities).
• At higher locations, the water has more “potential energy.” However, as you go down, the “potential energy” decreases while the water pressure increases. The water flows out due to this pressure. Therefore, the higher the water pressure, the higher the flow velocity. In other words, the “potential energy” at the water surface is converted to “kinetic energy” at a hole, and the lower the hole, the larger the flow velocity.
• As such, the water has “potential energy,” “pressure energy,” and “kinetic energy” and their sum is the total fluid energy.

[Keywords]	fluid energy
[Reference]	“The Wonders of Flow,” Japan Society of Mechanical Engineering, Koudansha Blue Backs pp. 98-101