The Genecon turns easily when it has no load on it. However, when the leads are clipped together, the handle becomes very difficult to turn. These effects can be explained by the amount of work required to move electrons (or, in the conventional sense, positive charges) through the circuit. When there is no circuit to speak of (the first instance), no work is required to move what amounts to nothing at all. However, at maximum load, the Genecon's handle becomes difficult to turn because more work is required to move electrons (or positive charges) through the circuit. The electrons gain energy in the form of electric potential energy as the Genecon moves them against the potential gradient. When the light bulb is attached, this energy is converted to light and heat, and the electrons' potential energy bottoms-out, and they return to the Genecon to have their potential energy increased yet again.

Q2: Describe how lamp brightness changes with time.

Once the capacitor is charged and the Genecon is removed, the lamp lights, but gradually fades.

Q3: What does this tell you about the discharge of a capacitor as compared to the discharge of a battery?

This shows that the discharge of a capacitor is rapid and smooth from its charged state to its discharged state, whereas a battery--via its internal chemical components--can continue to move electrons (or positive charges, whichever you prefer) for quite some time.

Q4: How does the discharge of a capacitor compare to that of a battery?

 

The discharge of the capacitor is unlike the discharge of a battery. The discharge of a capacitor is relatively quick in comparison to a battery. Also, the output voltage curve is very different, because a battery will output the same voltage for a long period of time before it begins to drop off towards zero, while the capacitor will begin to decrease in output voltage immediately. This can be seen in the brightness of the light bulb, which starts off bright, but slowly and steadily gets dimmer as the capacitor discharges.

 

Q5: Why does the Genecon become a motor in part 3?

With the Genecon and the capacitor connected in series, if the handle on the Genecon is turned, the capacitor will be charged. Once the Genecon is no longer charging the capacitor, it becomes a return path for the discharge of the capacitor. This reverses the current flow in the circuit, and will cause the handle of the Genecon to turn in the opposite direction that it turned when charging the capacitor.

 

Q6: Draw a circuit diagram for each operation above. 

 

Q7: Try to determine what direction current would flow in the circuits you just drew.

Answer to Questions 6 and 7:

Represents conventional current

Q8: What would happen if you left the Genecon and bulb in parallel to the capacitor after you charged the capacitor. Try it. Describe and discuss the results and your prediction.

 

 

If the Genecon and the light bulb were connected in parallel to a charged capacitor, when the capacitor began to discharge it would light the bulb and rotate the handle on the Genecon. The brightness of the bulb and the speed of the handle rotation are both less than they would be if it were only the bulb or the Genecon connected in parallel to the capacitor.