Sound Mirrors

 Have any idea what this is?

Source: http://www.independent.co.uk

I saw this article in the Telegraph today about a 'time capsule'  found under the White Cliffs of Dover:

www.telegraph.co.uk/news/earth/environment/tourism/11750370

In it, was the mention of Sound Mirrors. Well, that got me digging a little bit for more information and I came across this:

Sound Mirror - how does it work?

(Source: http://www.greatstone.net/history/sound_mirror_model.htm)

An accoustic(sound) mirror works like a modern TV receiver dish, but uses sound rather than radio waves. Sound from an aircraft out at sea hits the mirror and bounces back to the focal point. There is a working model of a Sound Mirror by the Hythe Military Canal, just south of Hythe [walk south from Hythe RH&DR station down either side of the canal until you came to the footbridge, where you will see the Sound Mirror model on the west bank.                                                  see picture  right Here you can, with the help of a friend, try it out for yourself. One of you crosses the bridge over the canal to the platform opposite and facing the dish, speaks quietly. Although you will be over 25 yards apart, you should be able to hear your friend easily.                                                             see right

The sound mirrors of Great Britian were not the first time they were ever used!

Hop over to:

http://www.aqpl43.dsl.pipex.com/MUSEUM/COMMS/ear/ear.htm

You will learn the history of their development and see some great photographs, too!