Falling Water
Students drop water from different heights to demonstrate the conversion of water's potential energy to kinetic energy. They see how varying the height from which water is dropped affects the splash size. They follow good experiment protocol, take measurements, calculate averages and graph results. In seeing how falling water can be used to do work, they also learn how this energy transformation figures into the engineering design and construction of hydroelectric power plants, dams and reservoirs.
Bridal Veil Falls, Yosemite National Park, CA.Copyright 2004 Microsoft Corporation, One Microsoft Way, Redmond, WA 98052-6399 USA. All rights reserved.
Engineers design hydroelectric dams to take advantage of the conversion of water's potential energy to kinetic energy, and then mechanical energy to electrical energy. Since the force of kinetic energy is dependent on the height and mass of the falling water, civil engineers take this into consideration when designing dam turbines. High kinetic energy (caused by a great amount of water or falling from a high distance) results in incredible force on the turbine blades, so engineers design the blade and the assembly to withstand this force. Engineers use this same understanding of energy transfer when they design roller coasters.
After this activity, students should be able to:
- Describe an object's varying potential energy as being dependant on its height above the Earth's surface.
- Explain the path of potential energy converted into kinetic energy as objects fall.
- List ways that the energy of falling water is used to do work.
- Describe how engineers use the potential and kinetic energy measurements of water to design reservoirs and hydroelectric power plants.