Sibo and the rainbowDid you know that 2015 is International Year of Light and Light-Based technologies?

Probably we mostly think of light as being that stuff that Eskom turns off every now and then, but it’s more, much much more.

Can you think of some other ways that light is used?

Hmmm… what about CD or DVD players – they use lasers. In 1982 CD players became the first laser equipped device readily found in the home.

Ooohhh – but what exactly is a laser?

Well, regular light from the sun or from a light bulb really contains all the colours of the rainbow. But you have to split it up to see this. You can split white light up into its colours using a prism (raindrops act like tiny prisms when they make a rainbow in the sky).

A laser is a special source of light of only one pure colour (or wavelength). You can’t break up laser light into other colours.

So what is so cool about laser light?

They can focus. It’s not like a torch at all. Just think when you shine a torch, the beam of light goes wider and wider. But a laser beam can be focussed to a very small spot (it does not spread out) and can shine for long distances.

That laser spot contains lots of energy. So much so that it can even be used for cutting stuff like thick metal.

Even more exciting, small laser beams are used in surgery, like scalpels.


BUT… lasers can be extremely dangerous if used irresponsibly. Recently, some kids at school got permanent eye damage from fooling around with laser pointers. In fact, you are now no longer allowed to take lasers to school in the Gauteng province. Shining a laser pointer into somebody’s eye is just silly. Don’t do it.

We haven’t even touched the surface about all the cool stuff lasers can do. If you know of some other uses of lasers – why don’t you write me a letter care of the African Reporter – I’d love to hear from you. Or email me.

If you visit my website – you’ll find a cool experiment on how to bend light.


Cool word for the week: Photonics

Meaning: Photonics is the science and technology of generating, controlling and detecting photons, which are particles of light.

Example: When I grow up I want to study photonics.

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