An enamel wire wrapped in a small nail results in a very simple electromagnetic experience to be made. Only 3 components are used in this experience where a nail attracts small metal objects such as paper clips, nails, pins, razors, etc.
Note: Ideal for STEM.
What to explain:
When an electric current flows through an enamelled wire wrapped in a nail, a magnetic field is created that magnetizes this nail, that is, it turns it into a magnet capable of attracting small objects.
However, the magnetic field will only exist as long as the circular current.
Thus, only when pressing the pressure switch S1 that establishes the current in the circuit does the nail magnetize and attract the objects.
Explain that the force of attraction depends on the intensity of the current in the coil wound on the nail and its number of turns.
Make a poster showing the magnetic field created around the nail and place some devices and mechanisms that make use of this type of electromagnet, such as cranes that raise huge steel sheets in mills and even in material deposits.
Show that the magnet can not attract non-ferrous metals such as copper, nickel and aluminum.
Assembly:
In figure 1 we have the scheme used to represent the circuit of the electromagnet 3 the aspect of the assembly.
To wind up the electromagnet get fine enamelled wire taken from some old transformer, motor or even reactor.
The wire should be light brown, because if it is darkened, a sign that the component is burned will not work.
The heat destroys the thin layer of enamel that insulates this wire.
A nail is used to serve as a mold for the yarn.
At the switch connection points X and wires of the battery holder, the wire must be scraped.
For batteries, use a suitable holder.
Do not keep switch S pressed for a long time, so as not to exhaust the batteries quickly and not to overheat the electromagnet.
Material list
B1 - 3 V - 2 small, medium or large batteries
S1 – Push Button NA
X1 - Electromagnet - see text
Several:
Support for batteries, enameled wires, clips, pins and other objects to be attracted by the nail.
