Electricity is the motion of electrons
in a wire. It's these moving electrons
that allow light bulbs to produce light, fans to turn, microwaves to produce
heat, ...
- Electrons moving in a wire, running a fan -
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To get the electrons to move requires energy.
Fortunately the sun supplies us with this energy by sending us energetic photons.
It's these photons arriving from the sun and
hitting our solar panels that cause electrons ultimately to move down a wire.
- Solar energy to panels -
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What happens when the photons hit the solar panels? As the next diagram shows, panels, like
everything else, are made up of atoms
and atoms contain electrons. When a photon hits an electron, the photon is absorbed
by the electron. The photon's energy is also absorbed by the electron. Since this
electron now has more energy, it breaks free from the atom.
- Photon giving up energy to electron. Electron moves free -
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But if that were all there was to it then we'd just have a bunch of loose electrons
moving around randomly. Something has to organize them to get them to move in one
direction down a wire. Doing that is a big part of the solar panel's job. The
solar panel is made up of two layers of slightly different materials. Keeping the
explanation simple, the result of the two layers is that these free electrons get
pulled to one layer and away from the other layer, resulting in the electrons moving
in one direction only.
- Due to the properties of the two layers in a panel, electrons move in one direction -
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If we then connect one end of a wire to one of the layers and the other end
of the wire to the other layer, these electrons that have gotten their energy
from the photons and that have been forced to move in one direction only, will
now move along the wire. And if we go further and split the wire somewhere along its
length
and put an applicance there, one that works using moving electrons, then we will
be powering that appliance (e.g. the fan in the following diagram.)
- Electron flow in wire, powering fan -
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