Lab 12: Current, Voltage and Ohm's Law

We started the day by lightning up a bulb through a wire touching either the positive or negative end of a battery and at the same time touching the base of the light bulb. The bulb lights because the wire transfers the electrical current from the battery onto the filament of the bulb, which gets so hot that it glows and give off light.

 In this picture we drew conditions when a bulb will light and when it won't. 

 We used two batteries, and the result of it was that the bulb's light got brighter because there is more energy provided from the power supply which is then used by the bulb.

 Professor Mason introduced the electroscope. He first rubs a rod with animal fur, and then places it on the top of the electroscope. The charged rod transfers the charge into the electroscope which gives the plates the same charge, causing them to repel each other.

 We then work with an ammeter to measure the current flow from the battery to the bulb and then to the ammeter. Later, we measure the current flow through the battery onto the ammeter and then into the bulb. We noticed that the current is the same in both cases, meaning the current in a circuit is always constant, because only energy is used up through the process.

 This is a example problem in finding the drift velocity of electrons through a 12-gauge copper wire.

 Professor Mason introduced use voltage, current and power, and their respectively units.

We then conducted an experiment using a nichrome wire, is a wire used in toasters. This experiment demonstrates Ohm's law by looking at the relationship between the applied voltage across a resistor and the current through the resistor.

 By looking at both graphs we can say that they are relatively proportional due to their linear relationship between each other.

 Finally, we looked into factors that affect the resistance of wires. First, it depends on the resistivity of the material, which is proportional to the resistance, it is proportional to the length, however is it inversely proportional the area.