### Short Circuits Lab

A short circuit is a circuit that includes no resistance. Short circuits are dangerous, but also very interesting, and sometimes counterintuitive. To learn about short circuits, we are going to build some short circuits using only one battery. Don't worry, as long as we use only one battery, nobody will get hurt, and this is a good way to build and play around with short circuits without the danger.

#### Materials

• A single D battery (only one! Do not take more than one!)
• A battery holder
• A single light bulb
• Several wires

#### Procedure

1. Put the battery in the holder and connect one end of the battery to the other, without including any light bulb in between, only a wire:

This is a short circuit! That is because there is a working circuit, but there is no resistor (like a light bulb in the circuit) Wait for a few minutes, and the battery might become a little bit warm. After this happens, disconnect the circuit!
2. Is there electric current running in your short circuit? How can you tell?
3. Short circuits are dangerous because, with no resistance, there is a very high amount of current! Remember, $$V = IR$$ and $$I = \frac{V}{R}$$, so if $$R$$ is very low, then $$I$$ is very high. People often believe that high voltage is very dangerous, but it is actually high current that tends to make danger. When there is high current is when you start to feel your circuit get warm. In fact, most household items can take only about 15 amps before they break.
Look at the voltage of your battery. If the wire provides only 0.1 Ohms of resistance, find the current and power of your circuit with the formula $$V = IR$$ and $$P = IV$$ Do you think this is safe? [Don't worry, I made up these numbers..it doesn't actually have that much current in reality.]
4. Is wrapping a battery in tin foil a good idea, or a bad idea? Explain why.
5. Shorting a Light Bulb: Connect a light bulb to a battery so that it lights: