• Question: How does light form?

    Asked by jberg to Amy, Drew, Julia, Kimberley, Sara on 21 Jun 2011.
    • Photo: Drew Rae

      Drew Rae answered on 20 Jun 2011:

      Hi Jberg. Light is made up of things called photons. Photons are little packets of energy that behave in strange ways – they aren’t really solid things the way we are used to things being solid.

      Photons can come from a couple of sources – they can come from electrons changing their energy level (that’s what happens in fire or a lightbulb), or they can come from nuclear reactions (that’s what happens in the sun).

    • Photo: Amy MacQueen

      Amy MacQueen answered on 21 Jun 2011:

      Light is simply a name for a range of electromagnetic radiation (of the electromagnetic spectrum) that can be detected by the human eye.

      Electromagnetic radiation has a dual nature as both particles and waves. One way to look at it is as changing electric and magnetic fields which propagate through space, forming an electromagnetic wave. This wave has amplitude (which is the brightness of the light) wavelength (which is the colour of the light) and an angle at which it is vibrating, called polarization.

      And as Drew said it is made up of photons! 🙂

    • Photo: Julia Griffen

      Julia Griffen answered on 21 Jun 2011:

      Hey Jberg… Light is part of the electromagnetic spectrum, which mean light is a form of energy and energy comes in the forms of waves. Light can be separated into the different classes of visible light using a prism to give us a rainbow effect.. (think I did this at school.. maybe you have too?) SO white light is made up of different coloured lights. Each different colour has a different energy. Red light having the lowest energy. Purple light having the highest energy. That’s because the purple and red light have different waves of different energies…. Doesn’t exactly answer your question but should give you some pointers if you were to look into this further on the internet etc… hope I’ve kinda helped :-S

    • Photo: Sara Imari Walker

      Sara Imari Walker answered on 21 Jun 2011:

      Oh cool question!! Light is in fact composed of tiny particles called photons. Photons are amazing. As Amy has described these little particles are what mediates electromagnetic interactions. Any electromagnetic interaction is mediated by the exhange of photons – that is how electrons and protons can interact – they exchange photons! What’s cool then is that photons are created and destroyed all the time, every time two particles interact electromagnetically!! And that’s a lot. There also a bunch of light particles in the universe left over from the big bang. Early on in the universe electrons and protons combined to form the first atoms – atoms are electrically neutral – so the universe became transparent to electromagnetic radiation. This means light was getting destroyed less frequently because it interacts with matter less in the atomic state. So today we have a bath of photons called the cosmic microwave background radiation all around us. This is a fossilized relic of the Big Bang!!

      See why I love light (and as such photon particles) so much?!!