ne. Remember, to get the turbine to spin quickly, they should tape the blades to the turbine in such a way that wind from the hairdryer will hit the blades with a great deal of force or such that the surface area and the angle of the blades will be maximized.
Instructions for Setting Up the Generator and Voltmeter and Adhering the Propeller (Turbine) to the Generator
Using masking tape, tape a ruler to a desk making sure that at least 5 cm of the ruler is extended off of the table. With the rubber band or electrical tape, attach the toy motor/generator to the part of the ruler that is extended off of the table making sure the shaft of the motor/generator is suspended off the edge of the ruler. This will give some distance between the turbine and the table such that the blades of the turbine do not hit the table. As a practice test, the instructor should attach the turbine that they he or she creates to the shaft of the generator to ensure that the distance between the blades and the table are sufficient to prevent any interference of the blade movement by the table. Wires should be connected from the generator to the voltmeter such that a voltage is registered when the generator’s shaft is rotated. The clay should be placed into the wide mouth straw (central axis of the turbine) to allow the turbine to “stick” to the shaft. By blowing a hairdryer across the turbine, it should rotate, consequently registering a voltage on the meter.
Introductory Discussion Talking Points
The teacher should approach the introduction of the lesson the way they deem most beneficial to their students. However, the key is to allow the students to become active participants in their own learning using prior knowledge, experience and self-inquiry.
Engage the students in a discussion in which they express what they know about wind, electricity and how wind can be harnessed to power an electrical generator. The following video may inform your teaching:
A discussion of how fossil fuels generate electricity should take place. Emphasis on the use of heat and turbines to actuate electrical generators should be emphasized. This can also be a research activity as a preamble to the design activity. Students can identify the kind of fuel and generation system being used in their community, perhaps organizaing a field trip to the power generation plant.
The following are points to cover during the introductory discussion:
- Gases and their properties (air in particular)
- The nature of electricity and electrical generators
- A brief discussion of fossil fuels, their depletion and how they impact the natural environment
- Alternative fuel sources (wind in particular)
- Wind turbines, their design, and how they function. You can share the following Wind Turbine Animation with students as a way to frame this part of the discussion:
Wind Turbine Animation
- The fact that wind turbines can transfer mechanical energy into electrical energy. You can have students compare/contrast steam generated by a fossil fuel boiler and wind as energy source. (NOTE: The students will conduct experiments to find out HOW this transfer takes place.)
Discussion Following Procedure Part 2: The Competition Round 1: What Effect Does Temperature and Pressure Have On Gases?
After part 2 of the procedure (below), start a new discussion in which the students are asked to consider the behavior of air (which is a gas) and how wind is formed. Ask students what affects gases and their movement. After a few responses, discuss how temperature and pressure affect how gases behave.
Refer to the attached document (What Effect Does Temperature Have On Gases?) for a demo and in-class experiment that can be used to further the discussion.
Consider what happens to warm air as it rises. When a gas is warmed, the molecules comprising the gas are not as closely packed together. As temperature decreases, however, the molecules come closer together. This closeness of molecules reflects the density of the gas as given by the equation:
Density = Mass/Volume
Thus, as the volume increases, the density decreas