A 2v Power Supply
- An Ammeter
- A Variable resistor
- An Iron Bar
- Wires
- Crocodile clips
- 100 Paper clips
Method
To carry out the investigation, I will first collect all apparatus and set up the circuit (as shown below). Then I will start with OA and eventually increase to 3A by altering the resistance. The current at which I will record the number of paper clips will be every 0.5 of an amp (e.g. 0 , 0.5 , 1 , 1.5 , 2 , 2.5 , 3). To make the experiment more precise and reliable, I will repeat the investigation so I have 2 results for every 0.5 of an amp, I will then make an average number.
Prediction
I predict that when the current is increased, the electromagnet will become more powerful, and therefore will hold more paper clips on it.
To support my prediction I have included a quote by Encarta Encyclopedia:
An electric current passed through a coil induces a strong magnetic field
Diagram
Below is a circuit diagram of what the experiment will look like:
After carrying out the practical experiment, I recorded the results and worked out an average, both of which are displayed in the following tables:
Analysis
By looking at the tables above, I can tell that the biggest amount of current, which is 3A , has the most paperclips attracted to the electromagnet. The lower amounts, such as 0A and 0.5A do not have any paperclips attracted to the electromagnet.
To prove my results furthermore, I have presented them in a graph (next page) with a curve. The graph shows that at 3A there are 72 paper clips attracted to the electromagnet. 3A is the highest point on the graph, which proves that as the current increases, so does the number of paper clips
The scientific explanation for this is that when current flows through a wire, a magnetic field is generated. When the wire is wrapped around an Iron bar, the magnetic field magnetises the Iron bar, which makes it attract to metal objects (paper clips in this case).
These results also fully support my prediction because there is a stronger magnetic field as the current increases.
Conclusion
I think my method of carrying out the experiment, was a good and reliable one because when repeating the experiment there was only a 3 paper clip difference.
As there was only 3 a paper clip difference, I think the experiment was carried out accurately. To improve the reliability of the results I could have repeated the tests again, but I am certain there will always be a maximum of 3 paper clips difference.
I think my results are good enough to support a firm conclusion that when the current is increased, so is the strength of the magnetic field.
To improve my investigation I could change the supply voltage, change the number of coils around the Iron bar and even increase the amperage to make the investigation longer.
