Electricity Monica Smith Summary of Demonstration: This experiment will show us how energy current moves through circuits. I will be pointing out the different parts and telling what they do, and how they contribute so that the energy flows through them all. Finally, I will close the cardboard piece so that everyone will be able to actually see the result of the electric current. Scientific Explanation: To explain my demonstration and how it works, we will have to start all the way back at electrons. As we all know, electrons have a negative electric charge and protons have a positive electric charge. The two are like magnets in that you cannot separate them and they repel each other, which is the reason for their constant activity.
This activity is better known as electrical force, which just means that like charges repel and alike charges attract. Electrons can move from object to object and when we acquire an excess of them it is released when say we touch a metal object. The electrons are released and we get a little shock from it. Now how do we pick up these electrons? For example, when you scuff your feet across the floor. This picks up negative electrons and it becomes confined to you until they are released. Now when we touch the metal doorknob the electrons are released because metal is a good conductor.
Metal lets the electrons move about freely whereas plastic does not allow this. That is why plastic and woods are grouped as being electrical nonconductors and also insulators. That is why we used the plastic coated wiring in the experiment because they insulate so that the current does not go anywhere. Now just as a magnet has a magnetic field the electric charges have an electric field. So how do we use these electric charges? Since the charges repel one another, work must be done to move them in or out of their field (electric potential energy). We get the term volt that is the measure of work done between two points, or energy transfer.
Electric current is the charge that flows. To maintain this flow you have to keep the separation of charges, which pushes the charges through a conductor. So the charges move to a higher potential and so they do the work as they come back to a lower potential. The battery is our example of giving charges a higher potential, because it provides the source of energy to do so. The light bulb is where the actual work is done in the circuit.
The plastic wires that are being used are means for the electric current to stay on a continual path. So our potential difference in this experiment between the two wires is in the work done by the battery that creates a higher potential energy, and the work done in the light bulb. The battery is the voltage source whereas the light bulb is the voltage drop. When we connected the wires to the battery and the light bulb the electrons don't move along a smooth path in one direction, but are bombarding with other electrons and positive ions. So it is more like a zigzag motion flowing in one direction. The rate of the current when there is voltage depends on: 1.
How many electrons there are in the wires 2. The charge of each electron 3. The drift velocity, (the material of the conductor and the temperature). 4. The area of the conducting wires (which just means that the longer the wires we use the more resistance and the shorter the wires we use then less resistance).
So depending on those things, it makes the collisions that are needed to make our light bulb glow. Of course our light bulb does not glow unless we make the connection complete by closing the cardboard. We complete the circuit by using aluminum foil on the bottom of the cardboard. The reason we used the aluminum foil on the bottom was because it completed the circuit. Aluminum foil offers very little resistance because of its properties. I hope you have a better understanding of the way my experiment works.
Electric current can be summed up in saying that first an electric potential establishes the electric field though a circuit. Secondly, that circuit causes a flow of current and finally, through the average velocity the electrons move slowly, even though the electric field moves them at the speed of light.