Science Projects Index
The effect of pressure on ice
Pressure can cause ice to melt. To observe this, let's do a simple experiment.
Take an ice block which is about the size of a brick. Now put a thin metal wire over it and on both the ends of the wire, you hang heavy bricks. Keep it like this for some time. You will find the metal wire cutting through the ice block and going down.
But you will notice a strange thing. That is, while the part of ice under the wire is melting and allowing the wire to go down, the ice above is continuous fusing together so that the wire seems to be embedded in the ice.
Soap and Surface Tension
One of the effects of washing soap is to reduce surface tension of water which helps in allowing the water to clean better. Now this effect can be seen by a small experiment. Do you remember the needle you floated on water
in an earlier experiment?
Well, do the same procedure and float a needle. Then put a little soap powder, just behind the rear of the needle. You will notice that needle is moving away.
This is because surface tension is disappearing in that area and the molecules are moving apart. If you continue to put some more soap powder into the water, a stage will come when the needle won't be able to float in that water, as there will be little surface tension left.