This experiment shows how a cell phone, can lose it's connection by being
wrapped in aluminum paper and when trying to call it, nothing happens. But why does
this happen? Lets see:
It is known that cell phones send and recieve information by
radiocommunication and these are transmitted from the phone to the nearest base
station (Switching centre) and the signal recieved is sent by this Switching centre to the
cell phone with a slightly different frequency
Illustration 1: Example of a telephone switching center connecting 2 cell phones
Besides this, these are coverage areas of the operators called cells, where in
each one there is a base station, has an amplitude to emit and receive information. It is
understood that a mobile device moves or changes its position around to the cell tower,
the magnetic flux passing through the antenna also changes due to the variation in
angle and distance. This magnetic flux variation creates an electric movement
induced in the antenna of the device.
Ilustración 2:
Example of a mobile
phone base.
“Lost Call”
When in the experiment the cell phone has the
aluminum foil placed around, it acts as a
"Faraday cage", this is a structure designed to
block the entry or exit of electromagnetic
fields, where electromagnetic waves are
prevented from entering the interior of the
object, since aluminum is induced, causing the
magnetic field to interfere with the original
(electromagnetic field that would go to the cell
phone).
When the aluminum foil has the electrons
located on the external surface, an electric field
is produced that cancels the external field,
causing them to reach a field value equal to
zero inside the cage, making their magnetic flux
zero.
The electromotive force in the cell phone,
generated by its antenna and the cell phone
network, is affected by the aluminum foil. The
cell phone's electromotive force is used to
amplify and process the electromagnetic signals that receives and to transmit the
signal it emits. By wrapping your cell phone in aluminum foil, you are partially or
completely blocking electromagnetic waves from reaching the antenna, which
decreases the antenna's ability to generate adequate electromotive force and
process signals. As a result, the mobile phone signal is weakened or cut off.
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