Electro-Magnet

Electro-Magnet

In our project, we tried to show that it is possible to create a magnetic field using an eletric current, like Oersted once showed us. In order to do so, we made an experiment, whose purpose was to build an electro-magnet.

In the first place, we needed materials that could be found easily at home. We needed a battery, a nail and a copper wire. We started by wrapping the wire around the nail, and connecting the two ends of the wire to the battery. Copper is a good eletrical conductor, so, by doing this, we were creating an eletric current and, with it, a magnetic field.

To do this experiment, we need to be careful with the materials, because we are using electricity but we also need to be careful with the temperature of the copper wire, because it will increase very fast. This happens because of the Joule Effect.

The Joule effect was discovered by James Joule. James Joule was a British physicist who was born in 1818, and died in 1889. The Joule effect tells us that electric energy turns into thermal energy due to  to the resistance of the electric conductor, which is the way a body opposes the passage of the eletric  current . In other words, an appliance, in this case mainly the copper wire, will heat up  connected to the battery. Although the copper wire is a good electrical conductor and its eletric resistance is low, all bodies have resistance. So, even if this increase of the heat is minimum, it is present in all bodies.

With this experiment we were able to reach the same conclusions as Oersted. Hans Christian Oersted was a Danish physicist and chemist who was born in 1777 and died in  1851. Oersted discovered that electric currents can create magnetic fields. In 1820, Oersted  carried out an experiment that proved the relationship between magnetism and electricity, opening,  thus, the path to the development of electromagnetism. He began by observing that the  needle of a compass swayed when there was a thunderstorm. Later, it was found that the current  circuit moved the needle from a nearby compass. This  compass behavior was only justified if a magnetic field was present. Like this  Oersted concluded that an electric current would produce a magnetic field.

Taking all this into acount, we learned that an eletric field can produce a magnetic field and, with this, that it is possible to easly create an electro-magnet at home, with materials that we use in our everyday lives.

Work done by:

Afonso Castanhola, nº1, 11ºA

Duarte Franco, nº4, 11ºA

João Neves, nº10, 11ºA

Rodrigo Silva, nº 19, 11ºA