Stranger than me?
Without light nothing on Earth would survive. Beaming down from the
Sun, either on an extremely bright summer morning or dim winter’s
afternoon, light is always around us.
Light is in many forms: from large waves that give echoes from the
furthest reaches of the universe or from the very smallest waves that
enable us to see information locked away in the smallest things possible.
Light is not as it seems, it exists almost as two separate entities but one at
the same time (Just as I am a Gemini)! It is a wave much like the ocean
waves that are smooth and constant. But yet it also exhibits a very much
more chaotic characteristic, as particles (photons) that stream away.
Light will diffract as do all other waves. This is when it passes through a
hole or a slit that is close to its wavelength (how far away the peaks of the
wave are) and turn into a circular pattern rather than in lines. We see this
often this year in our physics course. Imagine ocean waves entering a
harbour, as they come from the ocean the peaks of the waves are straight.
As they enter the opening for the boats they spread out into these semicircular waves (As in the harbour in Greece, last year). Diffraction only
occurs when the hole is smaller than the wavelength. Light’s wavelength
is around one hundred million times smaller than an ocean wave, so you
need a very small hole. These small holes are present in the spaces
between atoms and molecules. By shining light with very small
wavelengths on substances and seeing the diffraction pattern, we can
almost see individual atoms and their structures.
Light doesn’t want to be as simple as this though. If you were to view it
as particles it does not obey the wave rules. If you were to shine a light
through a slide onto a photographic plate, but so slowly so that individual
photons were produced, a picture of the slide would build up. A dot of
light here and a dot of light there, as each of these dots is where a photon
has hit. They can appear in any order but will always produce the same
picture, given enough time. It’s almost as if each photon of light knows
where to go and what the last photon has done.
This is very strange as particles do not diffract and waves give their
energy in a smooth continuous way, not in little chunks. So is it a wave or
a particle, no it’s both. In Physics this is what we call the wave-particle
duality. Actually this is not the full story as particles such as atoms or
electrons exhibit wave characteristics. So is it a particle-wave duality or
wave-particle duality?
Either way this is weird being two things at once that are completely
different.
Physics is strange, you say I am, so I suppose it takes one to know one.
495 Words
Aiden Dunne
Dr.Bremmer