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    (Original post by love_4_ducks)
    well surely everything is made out of atoms
    no. matter is made out of atoms. (actually atoms are made out of smaller things, called sub-atomic particles, which are made out of quarks and leptons). energy isn't.
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    Actually everything is made out of waves (or can have wave like properties). Electrons behave just like light in a double slit experiment. Whether something is a wave or a particle depends on which experiment you do.

    If you use the double slit experiment light behaves in such a way that can only be explained throught it being a wave, but the photo-electric effect can only be explained through light being made up of particles, normaly refered to as photons. So light is both waves and particles, but not at the same time.
    Photons are elementary particles that are classed as exchange bosons. This means that they are massless and must travel at the speed of light (except in an Einstein-bose condensate, but that's another story).

    But light is definetly not made up of atoms, which are different types of particles made up of other particles, some of which are again made up of other elementary particles.

    It's all very confusing, but then again modern physics is very confusing.
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    (Original post by haakon)
    Actually everything is made out of waves (or can have wave like properties)...
    good post

    (Original post by elpaw)
    the two slit experiment has nothing to do with photons, it proves the wave nature of light. it is the photoelectric effect that proves the particle (photon) nature of light.
    Sorry, I wasn't very clear. I know the normal two slit experiment proves that light acts like a wave, however I was talking about the variant where photons are fired through the experiment one at a time, yet still gradually build up an interference pattern. To do this, the photon must have to go through both slits at once and interfere with itself, which sounds absurd.
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    (Original post by haakon)
    This means that they are massless and must travel at the speed of light (except in an Einstein-bose condensate, but that's another story).
    Photons always travel at the speed of light, however, since they might be absorbed and emited from atoms, the apparent speed can be less, and in some rare cases even greater, than the speed of light in vacuum. Frequently, one tend to use the wave model of light to explain the decrease in light speed when it passes through a medium.

    A bose einstein condensate is a special case because its atoms act as bosons. This is possible since the total spin of the atoms is a natural integer ( fermions have spins which are halves of integers. Since the atoms behave like bosons, they may occupy the same quantum state, thus they act as one single particle. This particle may absorb photons and emit them again (just like in any other medium, such as air). What makes a bose-einstein condensate so special when it comes to the interaction with light is its extreme refractionary index. The velocity of a lightpulse passing through a bose einstein condensate decrease to about 60km an hour. Thats almost a factor of 75 million. Compare this to dry air where the speed of light is only decreased by a factor of 1,0028.
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    (Original post by elpaw)
    no. matter is made out of atoms. (actually atoms are made out of smaller things, called sub-atomic particles, which are made out of quarks and leptons). energy isn't.
    Energy is property of a system, and is not to be confused with radiation. Even though photons have zero rest mass, it is wrong to say that photons are energy. Energy is just one of several properties a system or a particle might posess. Other properties include charge, mass, velocity, momentum, spin, parity etc etc. Several of these properties are interlinked. As an example, energy and mass are equivalent.
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    You just had to correct me didn't you Jonatan? Eventhough everything i said was correct. It should be because parts of it i learned from you (although not all). Oh well, i guess i couldn't expect you to say away from a discussion about quantum physics.

    Btw, i was just about to enter the discussion about drugs, but then i realised that probably wasn't a very good idea considering how our last discussion on the matter ended (it didn't). So don't think your arguments are uncontestable, and that your 100% right, the picture is more nuanced than you present it.
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    (Original post by love_4_ducks)
    well surely everything is made out of atoms
    well if light was, when u are walking around in a lit room, wouldn't u bump into 'light' then?
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    (Original post by C0nnie)
    well if light was, when u are walking around in a lit room, wouldn't u bump into 'light' then?
    Atoms are mostly empty space with a tiny nucleus at the middle (thank Rutherford for that).
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    (Original post by C0nnie)
    well if light was, when u are walking around in a lit room, wouldn't u bump into 'light' then?
    you can bump into light. photons do have momentum, it's the way that sun sail on a spaceship works, and also how it is possible for lasers to propel spacecraft.
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    (Original post by elpaw)
    you can bump into light. photons do have momentum, it's the way that sun sail on a spaceship works, and also how it is possible for lasers to propel spacecraft.
    isn't that to do with the fact that photons are packets of energy, so the energy is transferred to the sunsail and spacecraft? but i spose they have to hit the photons to get the energy transferred....
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    (Original post by C0nnie)
    well if light was, when u are walking around in a lit room, wouldn't u bump into 'light' then?
    Yes, you are. In fact, if the light did not bump in to teh electrons in the molecules of your rethina, you woul not be able to see anything at all...
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    (Original post by haakon)
    You just had to correct me didn't you Jonatan? Eventhough everything i said was correct. It should be because parts of it i learned from you (although not all). Oh well, i guess i couldn't expect you to say away from a discussion about quantum physics.

    Btw, i was just about to enter the discussion about drugs, but then i realised that probably wasn't a very good idea considering how our last discussion on the matter ended (it didn't). So don't think your arguments are uncontestable, and that your 100% right, the picture is more nuanced than you present it.
    Well, the main point was that photons ALWAYS travel with the same speed. Photons are massless particles and could not exist at any other speed than the speed of light in vacuum.
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    (Original post by C0nnie)
    well if light was, when u are walking around in a lit room, wouldn't u bump into 'light' then?

    well, air is made from atoms and molecules, and yes, you bump into air atoms/molecules all the time, you don't notice thought because you're used to it... We wouldn't live very long walking through a vacuum.
 
 
 
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