Prediction:
I predict that as the number of turn of coils increase, the more weight the electromagnetic can hold. This is because when you increase the turn of the coil, the electromagnetic gets stronger. As increasing the turn of the coils is one of the factors that can increase the strength of electromagnet, therefore the electromagnet can hold more weight.
Preliminary Work:
In our preliminary work, we were trying to find the best way to get the result.
First we used different kind of apparatus, therefore the results will be different.
The apparatus we used is an iron (for conductor) instead of nails. Also we change the number of turns of the coils. Here is a table showing what we did our preliminary work.
When we did up to experiment 3, we found out that this method is not efficient therefore we change the method.
Method: (for final result)
- Get the apparatus from the apparatus list below.
- Set up the apparatus as shown in the diagram.
- Find out the maximum weight that electromagnet can hold with 10 turns of coils, 20 turns of coils, 30 turns of coils, 40 turns of coils and 50 turns of coils.
- Fill in the result table from result.
Apparatus:
Diagram:
Result:
Conclusion:
The graph shows that as you increase the number of coils, the average will increase. This is because increasing the number of coils is one of the factors that can increase the strength of the electromagnet. Therefore as the electromagnet getting stronger, the weight that it can hold will be larger. Also, there is a positive correlation between the number of coils and the average. This illustrates that if one of them increases, the other will increase as well.
From my result table, I can also predict that at 60 numbers of coils, the average will be between 1680 to 1780. This is because if we calculate the difference between each average, the answer will be about 300.
Regarding from my result, we can proved that my prediction is correct. This is because by looking at my result; the line of best fit has a positive correlation between the number of coils and the average. This means that the more turns of coils of the magnet, the more weight it can carry.
Evaluation:
According to the graph, there is anomalous result, which is the point (10,100). This point is specifically away from the line of best fit. This shows that this point is anomalous. For the reason that it may caused anomalous is we have used a different power box. Using a different power box causes anomalous result, because each power box has different resistance. Therefore the graph demonstrates that the first power box we used have a higher resistance than the second power box. Also we have used the different wires, which may causes anomalous.
We can also use another experiment to draw out the same conclusion as above, which is using the same method of increasing the turns of the coils, but instead of measuring the maximum weight, we put the conductor on the scale, and then measure how much the conductor is weight. The result of it is the conductor will weight lighter. The more turns of the coils there is on the electromagnet, the lighter the conductor will be. This is because as you increase the turns of the coils, there is more force is being pulled, therefore the weight of the conductor becomes lighter. There are also some factors that can affect the result, which is the way we wrapped the coils on the electromagnet. This is because if we wrap the coils closer together the effect of this is that the weight of the conductor will become heavier, because when the current flowing through the coils, it might flow through once instead of twice.
Fair test:
To make the investigation a fair test, we can:
- Use the same power box, therefore the amount of current flowing through the circuit will be the same, due to each power box have a different resistance.
- Use the same iron core, because different iron core have different size, material, which might affect the final result.
- Use the same voltage. Since if you increase the voltage, the electromagnet will be stronger, therefore it can hold more weight. However, as our investigation is about how the number of turns of the coils affects the strength of the electromagnet.
- Repeat the experiment three or more times and compare the results, because every experiment have different readings, so if we compare it, it will make it better.
- Making sure that when wrapping the bar magnet, it is all in one direction, this is because the direction of the magnetic field is depends on the direction of the electric current creating.
Safety:
In a science lap, there are many rules we have to follow to prevent the risks of having an accident.
- We do not run in a laboratory, because accidents may occur if we run.
- If you have long hair, tie it back, because it might get into your way during the experiment.
- Do not put your hand below the iron core, because when the electromagnet is not strong enough to carry the weight, it will drop on the table, therefore it will hurt your hand. Due to the iron core is heavy and hard.
- When carrying the weights, use both of your hands, because they might too heavy.
- When getting the apparatus, get one at a time, because when accidents happen, it will lower the risk of serious injured.
- Always wear goggles; this is because it can protect your eyes from blindness.
Reference:
- AQA Modular Science-“The Revision Guide” Edited by Richard Parsons.
- http://www.bbc.co.uk/schools/gcsebitesize/physics/electricity/electromagneticforcesrev2.shtml
- http://www.4learning.co.uk/apps/homework/index.jsp