Moving water

Simple syphon             Bending a stream of water

Another way to move water is to use a syphon. By using a piece of tubing, water can be transferred from a higher container to a lower one. Fill a bucket with water. Put one end of a flexible tube into the water and slowly lower in the rest of the tube so that it fills with water and there are no air bubbles. Holding one end of the tube firmly under the water, close the other end by putting your thumb over it and lift this over the edge of the container. Have a suitable container down below and guide the closed off end into it. When you release your thumb the water will flow uphill and out of the higher container to the lower one. Syphons work because atmospheric pressure acts on the surface of the liquid. In fact, if you had a long enough tube, you would find that atmospheric pressure would support a column of water 9.75 metres (32 feet) high!

Figure 14 - Syphon at work

Bending a stream of water

Pupils can try bending a stream of water using static electricity (Fig.15). If they charge a plastic rod or ruler by rubbing it on their clothing or hair and then hold it near a steady stream of water from a tap, they will find that water is pulled towards the plastic object.

Figure 15 - Stream bend

  Pouring oil on troubled waters