If you've read any of my previous blogs you will now be accustomed with the knowledge that LIGHT comes in the shape of PHOTONS. PHOTONS come in different wavelengths which denotes their "type" - IE really long wavelength is a RADIO wave and really short wavelength are GAMMA waves.
Next up - how PHOTONS are ABSORBED by ELECTRONS. Electrons absorb photons then emit them. When a PHOTON is absorbed by the ELECTRON, the electron "jumps" to an atomic orbital of higher energy and then "drops" back down when it emits the PHOTON - this happens exceptionally fast.
If you've read my BLOG on GLASS you'll know why it's transparent and why PHOTONS pass straight through the GLASS.
So picture a PHOTON - a massless particle travelling from the Sun to Earth. This PHOTON is of the VISIBLE LIGHT WAVELENGTH. Now picture the PHOTON passing through the windscreen of your PARKED car. It is then absorbed by an electron in an atom of the drivers seat. The PHOTON is then emitted by the ELECTRON but it CANNOT pass back through the GLASS! WHY?
If a PHOTON gives an ELECTRON ENERGY, that means it must be CARRYING energy - PHOTONS ARE ENERGY! So if the PHOTON gives its energy to an electron who then "uses" it to move up and down then gives the energy back - PART of the energy has been USED. The PHOTON that is emitted is of a LONGER WAVELENGTH as it has "lost" energy. The PHOTON is now of the INFRA-RED category. This means that the PHOTON HAS LESS ENERGY and is not able to PENETRATE the windscreen. The PHOTON CANNOT "leave" the car and causes HEAT build-up as it is absorbed and re-emitted by atoms in the inside of the car.
This principle is the SAME for GREENHOUSES and many other similar scenarios.
Thanks.
Much love, Adam. XX
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