Electric Potential 4/7/2014

Today we started with electrics.  We began with a small experiment of making the light bulb light up with merely one piece of wire and a battery.  We easily accomplished this. Nextm to make the bulb shine twice as bright, we just doubled the power supply in series

Eddie successfully hooking up light bulb OWNING Harvard graduates (even without alligator clips!)

For our first experiment of the day we used a resistor and connect it to an ammeter and power supply, in which only the voltage applied was known.  The catch here was to use a power meter to determine the voltage at the resistor.

Measuring the electric potentials going through the circuits as we go...

Homemde resistors using coiled up copper wires used in this experiment

For each trial we increased the voltage into the circuit using the power supply:

Our setup consists a voltage supplier and a resistor with an ammeter used to measure the current and a voltmeter was used to measure electric potential.

We plotted a graph showing the current vs voltage for the data obtained from our resistor and compared with the data from our neighboring group. 

The two lines were plotted and fitted with linearly which suggests that there is a linear relationship between current and voltage and that they are proportional.  From our graph, the slopes of the lines are actually the resistance of the resistors. In this case, different resistance as slopes of the two lines are different.


Next experiment, we measured the resistance of several different wires with unique characteristic of varying diameters and lengths. As one coil was made of copper and the rest were made of nickel-silver, we were to determine the resistance of each coil.

The graph clearly shows a proportional relationship between the length of the wire and resistance.

Plotting a graph of resistance vs length we get the curve shown above. Most of the points follow a positive linear slope, however two of the points were off for this graph but this is negligible and our result turned out to match our analysis: that is, when the length increased the resistance increased as well.