[ubuntu-za] [OT] - Off Topic - Wanted in Durban area : Dead DVD-writers

[Nic Roets]

On Mon, Mar 9, 2009 at 9:42 PM, Duncan Withers <duncan at theopenproject.org>wrote:

>
> On that note I am also looking for cheap *high power* laser pointers as
> they may also be suitable. The cheap/dodgy R15 beach front/corner shop
> types are not powerful enough.
>

A nice experiment to do with one of the cheap ones is to prove that light is
a wave. Take a small piece of glass, hold it over a candle to blacken it.
Then put two razor / knife blades on top of each other and draw two lines
across the glass (+- 1mm apart). Now aim the laser at the double slit
(clamps may come in handy) and you should see an interference pattern a
meter or two behind the glass.
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