E.M.F and Resistance
E.M.F and Potential Difference, connect a cell to two lamps in series and take a reading of the first lamp:I predict that the reading of the voltmeter will be less than the voltage of the battery we use.
E:M:F and Potential Difference, connect a cell to two lamps in series and take a reading of the second lamp:
I predict that the reading of the voltmeter will show even less than the voltage of the first lamp. Also less than the voltage of the battery.
E:M:F and Potential Difference, connect a cell to two lamps in series and take a reading of both lamps:
I predict that the reading of the voltmeter will show that the voltage gowing through the lamps will be a little bit less than the voltage of the battery.
E:M:F and Potential Difference, connect a cell to three lamps in series and take a reading of the first, second, third and all the lamps:
I predict the same thing for this experiment as for the previous experiments only that the third lamp will show even less than the second lamp.
When we connect all three lamps to the voltmeter I predict that the total amount of volts will be a little bit under the voltage of the battery.
Resistance, connect a dry cell to a lamp. Use a short piece of thick copper to connect one side of the lamp to the other:
I predict that the lamp will go out and show no light what so ever.
Resistance, use a 30 cm piece of nichrome wire to complete the circuit. Move the crocdile clips further apart/closer together on the piece of wire:
I predict that when the crocodile clips get closer together the lamp will shine more and when the crocodile clips move further away the lamp will become dimmer.
Results:
E.M.F and Potential Difference, connect a cell to two lamps in series and take a reading of the first lamp:
The voltmeter showed a reading of 1.5 volts which is the voltage of the battery we used.
E:M:F and Potential Difference, connect a cell to two lamps in series and take a reading of the second lamp:
The voltmeter showed a reading of 1.5 volts which is the voltage of the battery we used.
E:M:F and Potential Difference, connect a cell to two lamps in series and take a reading of both lamps:
The voltmeter showed 1.5 volts going through the two lamps.
E:M:F and Potential Difference, connect a cell to three lamps in series and take a reading of the first, second, third and all the lamps:
The voltmeter showed 1.5 volts. This is the voltage of the battery.
Resistance, connect a dry cell to a lamp. Use a short piece of thick copper to connect one side of the lamp to the other:
When the voltmeter touched both sides of the lamp the lamp turned of.
Resistance, use a 30 cm piece of nichrome wire to complete the circuit. Move the crocdile clips further apart/closer together on the piece of wire:
When we moved the crocodile clips further away from eachother the lamp became dimmer. When we then moved them closer to eachother the light started to shine more.
Coclusion:
From this experiment I can conclude several things.
I can conclude that the volts going through a circuit stay the same. It does not matter how many applictions you add to the circuit. The volts allways stay the same.
I can also conclude that electricity will always take the easiest way to get through the circuit. This means that if you make an easier path for the electrons to flow it will allway follow it.
I can also conclude that a battery pushes electrons around the circuit. The force that the electrons are pushed away at is called volts. Electrons are pushed away from the battery at the negative pole of the battery. At the positive pole there are no electrons being pushed out. The difference from the negative to the positive pole is called potential difference.
From these experiments I can also conclude that in a circuit there is resistance. Resistance causes electrons to flow slower. The more resistance the more volts are needed to push a current through the resistance. There are four things that can affect resistaance. The length, it takes a longer time for the current to flow through a short wire than a long wire. The cross-sectional area, if the cross-sectional area of a wire is big it is easier for the currant to flow through. Material, some materials conduct electrisity very well and other very porly. A material can even be an insulator and conduct no electricity at all. Temperature, when the temperature increases the resistance of the wire increases.
Discussion:
The information in my conclusion are used daily in our lives. We do not think so much about it.
When we want to make the current less in a circuit we use a resistor. This is used in several occasions everyday. For example in a light knob that you twist to make the light get dimmer or lighter. When we have the light on very dim then the resistor is letting through a little electricity but when the light is on for full there is almost no resistance.
When we have lights in our christmas tree there is a circuit like this:
In every lamp there is 1.5 volts. There is allways the same amount of volts in every lamp.
