K'nex generator

Introduction:

Harnessing energy from our vast water resources is one goal of the Green Revolution. Water covers over 70% of the earth and is a dense fluid. Therefore, the movement of water is able to create great forces to move materials. Perhaps the most common example of water’s force is shown by all of the sediment carried in streams and in rivers as a result of erosion. Just consider the Grand Canyon alone: thousands of feet of rock has been eroded and carried away by the force of the Colorado River. These three hydropower lessons use the power of moving water and can be done inside the classroom with proper attention to water management or outside providing there is an available source of water. As Students investigate water power they will explore K’NEX models as built from the Instructions Booklet and then they will optimize their models so that the force of the water is used more efficiently. Student observations and adjustments to the procedures and the structure of the models are important learning opportunities as students seek to optimize each model’s efficiency. Optimization is an important engineering principle and concept that is highlighted throughout the K’NEX Education Renewable Energy Set. Examining the energy that is available to the model (potential energy) and then how that energy is transformed into movement (kinetic energy) represent the focus of the three lessons related to water power. These two concepts provide real world contexts that state, regional, and local governments and their utility companies must consider as they evaluate the costs, benefits and limitations of proposed water use to generate energy for the future.

1. Build the Hydroelectric Generator model using the building instructions. The black paddles on the water wheel portion of the model should be suspended over the green tub as shown.

2. Explore the model and determine how it operates. Describe it’s operation below.

3. Turn the black paddle wheel gently with your hand and trace the movement of the parts as the energy you have added passes through the model.

4. Explain the flow of motion (energy) through the model.

5. Select one of the variables listed below to test the energy producing performance of the water wheel model.

• The height from which the water is dropped on the black paddles.

• The amount of water that is dropped on the black paddles.

Write down the selection you made and then describe how you will test the variable you have chosen.

6. What did you discover?

7. Write a single sentence that describes the effect of your variable on the performance of the water wheel system.