What Is Light Made Of?

Light moves at incredibly fast speeds, and it allows us to see everything in the world. What is it made out of? Trace is joined by Debbie Berebichez to explain how light is both a particle and a wave.

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"One of the most famous experiments in quantum physics, which first showed how particles can bizarrely behave like waves, has now been carried out on the largest molecules ever."

Young's Double Slit Experiment
"In 1801 Thomas Young was able to offer some very strong evidence to support the wave model of light."

Wave-Particle Duality
"Wave--particle duality is a theory that proposes that all matter exhibits the properties of not only particles, which have mass, but also waves, which transfer energy."

Double-Slit Experiment
"The double-slit experiment is a demonstration that light and matter can display characteristics of both classically defined waves and particles; moreover, it displays the fundamentally probabilistic nature of quantum mechanical phenomena."

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[sandenium]

so basically what they are saying is that still nobody knows what exactly light is.

[Theth]

Light, is not to be taken lightly!  :P I tried.. 

[scrapetv]

I'm no scientist, but I think it's at least possible light is made of Unicorn blood. I could be wrong but probably not.

[AceRazor]

Quantum mechanics is one of my favorite fields of science.

[AnotherCasualViewer]

i was expecting Morgan Freeman to show up, i was disappointed!

[marksmithwas]

Light is both a wave and a particle? That's not too surprising to me XD
I have this theory (It's probably already been theorised many times before) that a photon is a wave, is invisible but always exists. When it comes into contact with energy (eg a particle), then it picks up the energy (like mobile phones use carrier waves to send unique data depending on the phone number, AKA the frequency of the wave). When you see light fading, all you're seeing is the energy dispersing from the photon but the photon still exists. Think about it, a massless particle always will travel at the speed of light (aka the speed of a massless particle) and has no mass which means it passes through other matter. The reason why mirrors reflect light is because the energy that's manipulating the wave itself changes direction, and pulls the photon with it. At least, that's my theory

[KageRyuu]

Anyone else remember a documentary on BBC that aired sometime in 2011 done by Horizon called "What is Reality?" Yeah, seeing light change from wave to particle and back again depending on how it's observed is far more impressive when you see it happening in real time.

[lafcadiothelion]

she should be on the show more often, I really liked her explanations!

[DimitriosDenton]

Seriously, is there someone who didn't know about the double slit experiment before that?

[ekatehtderllip]

There seems to be great similarities between the nature of photons and the nature of electrons. Like most things, maybe the particle/wave dichotomy exists within a spectrum.

[dantemeriere]

I could listen to her all day. Loved her accent.

[fullyawakened]

It is not BOTH a particle and a wave... it is NEITHER a particle NOR a wave.  We just use those terms to help laymen understand some of the quantum characteristics and behavior we are observing.  You just confuse people when you say they act like both... they do not... they act like neither.

[bogdanelbogdan]

The one electron universe theory says is that the electron travels forward and backward through time creating multiple instants of itself considered by us electrons when it goes to the future and positron when it goes towards the past creating like this the space-time. When electron/positron interact(all the time) they create a spiral shaped motion (photon) like a twisted two way band. So a spiral (wave) is a path through space-time. Light is also a wave or a spiral therefore a path through space-time.

[maesr]

This is exactly what i'm doing in AS level Physics at the moment, thank you it helped so much!! :)

[MrGridStrom]

So that's why we need to sweep the floor; because of all the used up light particles gathering on the floor and in the corners of a room? I'm gona hold a cup under my light and full it up with little particles.

[peteranilov]

This is probably my favourite episode of DNews I've watched :)
It's just great how light is both a wave and a particle

[bits]

Veritasium has the best visual demonstration on this topic

[MrJarrah]

I think what everyone needs to understand is that these guys aren't here to produce a scientific paper. They're here (as far as I can tell) to introduce scientific content for people of all intelligence that is simple and easy to digest. They do a pretty good job.

[crooked-halo]

Is light subject at all to gravity? Does it "fall" with distance? What fascinates me is the theory (is it theory?) that light cannot escape the massive gravitational pull of a black hole.

[RodneyWilder]

In my universe, light is made of gummy bears and I'm going to eat them up.  nom nom nom