This produces an electromagnet. Coiling the wire around a soft iron core increases the magnetic effect. When an electric current flows through the coil it becomes a magnet.
I have decided to investigate increasing the strength of the electromagnet and therefore the magnetic field range of the electromagnet by varying the amount of coils present on the length of the electromagnet. In addition to this I will keep the amount of coils constant, 40 coils, and vary the current to see if this affects the strength of the electromagnet.
I will construct the electromagnet by coiling insulated wire around the length of a long nail made of iron and stripping the two ends of the insulating plastic. These ends will then be connected with crocodile clips to two main wires joined to the battery. When varying the charge I will add an ammeter to the circuit to enable me to take accurate readings of charge.
To actually test the strength of the electromagnet, I will lay it in a pile of paperclips and turn on the electromagnet via the power pack and see how many paperclips the electromagnet has been able to attract. This will be measured at a constant current of 6.4 amps and the variable, the amount of coils will be measured at 10, 15, 20, 25, 30, 35 coils. I will carry out both experiments twice to try and gain more accurate results and acquire a full picture of the experiment.
- Power pack
- Wires (connecting)
- 30 paperclips
- Iron nail
- Wire (to coil)
- Ammeter
- Crocodile clips
The current would be likely to change so I will keep it constant by observing the ammeter and correcting any fluctuations instantly. The soft iron core I use will be the same throughout the experiment so it doesn’t affect the magnetic strength of the electromagnet. The shape of the coils will be uniform and they will be evenly spaced. This is because if I keep the coils at one end only then this end will be more powerful than the other and I twill affect the results. The paperclips will be the same type and size so that they are not harder to attract, or easier as this would affect the results also.
Due to my background knowledge I predict that with the increase in the number of coils, the electromagnet will become stronger. This is because every turn of coil has its own magnetic field. When there are more turns in the same area, the coils magnetic fields overlap and this creates a stronger force.
The increase in current put into the electromagnet will increase its force also. This is because as more power is introduced to each coil, its magnetic field is increased and strengthened, causing the magnetic field to extend its previous limits and be able to attract more paperclips.
-Increasing coils when current was a constant of 6.4 amps
-Increasing current when number of coils was a constant of
My results show that the increase in current and increase in coils both result in a stronger magnetic field and therefore a stronger electromagnet. From my results, I can see that the more coils there are around the Iron Core the stronger the magnetic field becomes. This proves my prediction; I had confidently predicted that any increase in the number of coils would strengthen the magnetic field itself.
Due to my background knowledge I had predicted that with the increase in the number of coils, the electromagnet would become stronger. This was because every turn of coil has its own magnetic field. When there are more turns in the same area, the coils magnetic fields overlap and this creates a stronger force. In other words I had predicted that it strengthens the magnetic field due to the wire having its own magnetic field around the end of each of the tips of the wire. As the wire is bent into a coil this encloses the magnetic field allowing the field to over lap creating a more concentrated magnetic field. This is what increases the strength of the magnetic field.
Both graphs resulted in a rough linear pattern and I can clearly determine that with an increase in both factors there was an increase in the strength of the electromagnet and therefore the amount of paper clips was able to attract.
I had also investigated increasing the current flowing through the electromagnet and seeing if this allowed the Iron Core to attract more paper clips. I had predicted that increasing the current would also affect the strength of the magnetism. This was because the increase in current put into the electromagnet increased its force. This is because as more power is introduced to each coil, its magnetic field is increased and strengthened, causing the magnetic field to intensify and grow allowing more paperclips to be attracted.
The experiment I chose in my investigation was a good method to use as it effectively illustrated my prediction and was fairly simple to construct and carry out.
The results were very accurate and I had no anomalies, I think this was because I was very careful in trying to maintain one variable only and keeping all other factors constant by using, for instance, an ammeter to observe the current in a lot of accuracy.
The method may not have been entirely accurate as I am not sure that using paperclips to ascertain the electromagnets strength was the most accurate method, this is because it is hard to attach the paperclips once they have reached a certain length although this could have been because the magnetic field only reached so far. I am not sure how the method could be improved to gain more accurate results although possibly using a different material would be advisable.
Despite these queries I am certain that my results firmly support my conclusion as they match up with my background knowledge, prediction and follow a very clear pattern.
Further work could include varying the core used in constructing the electromagnet; I could investigate what makes the electromagnet stronger and weaker in the form of core material.
Lucy Gould 25th February 2002