The Sieving Machine

Almost all the materials to make this sieving machine I had in stock, or recycled or acquired very cheaply. It isn't as sophisticated as the one I have seen at the Natural History Museum but it works. It is based on an idea by David Ward of the Tertiary Research Group.

The working parts are two reciprocating lawn sprinklers attached by a hose pipe to a timer valve, all bought for very little money at Homebase. The coarser sediment settles out in two levels - a bread tray beneath the sieve and the bottom of an old cold water tank that used to be in my loft.