answers: Unusual Water

What you should have seen:

When the polythene strip was placed near the water, you should have seen the water moving towards the polythene. The water was attracted to the polythene.

What was happening?

When you rubbed the polythene strip with the cloth you were charging it. It had static electricity. By rubbing the polythene with a cloth, you knocked some negative electrons off the cloth. These negative charges went onto the polythene, giving it a negative charge. The cloth was left with less negatives, so it ended up with a positive charge.

The rod was charged positive. It also attracted the water to it. Two different charges will attract each other. This means water must have a negative charge.

Water, or H2O, is made up of hydrogen (H) and oxygen (O). The hydrogen in water has a positive charge and the oxygen has a negative charge. Water is called a polar molecule because it has a positive end and a negative end.

A diagram to show the charges on each atom in a molecule of water

Click here to find out more about the properties of water.

So why didn't the positive end of each water molecule repel (push away) the positive polythene rod? That's because attractive forces are much stronger than forces that repel!

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