Under Pressure
Students learn about Pascal's law, an important concept behind the engineering of dam and lock systems, such as the one that Thirsty County wants Splash Engineering to design for the Birdseye River (an ongoing hypothetical engineering scenario). Students observe the behavior of water in plastic water bottles spilling through holes punctured at different heights, seeing the distance water spurts from the holes, learning how water at a given depth exerts equal pressure in all directions, and how water at increasing depths is under increasing pressure.
Is pressure different at different water depths? In this demo of a soda bottle set-up with upper and lower holes uncovered, the stream from the lower hole spills further due to higher pressure.
An understanding of Pascal's law and hydrostatic pressure applies in many engineering and scientific fields. Engineers who design locks and dams use the known relationships between water depth and water pressure, as described in pressure laws, to estimate the amount of force expected to be exerted. They use these calculations to design functional structures that adequately meet community performance and safety objectives.
After this activity, students should be able to:
- Explain Pascal's law.
- Know that water pressure increases with depth.
- Calculate volume.