Lab 9-1A: Turn Out the Lights

April 18, 2009 Turn Out the Lights Julie Anne A., Block D


Purpose: To gain an understanding of the flow of electrons in a circuit.


Procedure: As described on p. 307 of BC Science 9


Data and Observations:


Circuit 1













Circuit 2














Questions:

1. I'm an electron leaving the negative terminal of the cell in circuit 1.

- There is only one way for me to get to the positive terminal of the circuit.
- I need to travel through two light bulbs.


2. When one bulb is removed in the circuit, the other bulb becomes unlit. This happens because everything in the circuit is connected together. If a bulb is unscrewed, the flow of electrons will be cut off because one of the elements where the electrons will travel and be passed on is disconnected. Because of that, the electrons will not reach the other bulb.


3. I'm an electron leaving the negative terminal of the cell in circuit 2.

- There are two ways for me to get to the positive terminal.
- I need to travel through two light bulbs.


4. In circuit 2, when one bulb is removed, the other one is still lit. This happens because each of the bulbs are directly connected to the battery. When one is unscrewed, it doesn't affect the direct connection of the other bulb in the battery. This is why the other one is till lit.



Conclusion:

In this lab, we confirmed the flow of electrons in a circuit by observing light bulbs.


In circuit I, when the other bulb is unscrewed, the other one turns off because the light bulb acts as a sort of switch, since everything in the circuit is connected. The unscrewing of a material will break the circuit and the flow of electrons. Also, when the two bulbs were connected in the circuit, the other one is very dim because there is not enough potential difference. When the electrons get out of the negative terminal, the first bulb it goes through recieves the most electrons and the other one recieves a little due to the lack of potential difference.


In circuit 2, when the other bulb is unscrewed, the other one is still lit because each bulb has a direct connection with the battery. This is also the reason why both of the bulbs are brightly lit. (Notice that in circuit 1, two light bulbs are connected to the battery, indirectly. Both of them has to share the potential difference of the battery in one flow of the electrons.)

This explains why circuit 1 could not light both lights.