Everything Science Grade 10

16.4 CHAPTER 16. ELECTROSTATICS

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- - - - +

This happens because when you rub the glass with silk, tiny amounts

of negative charge are transferred from the glass onto the silk, which

causes the glass to have less negative charge than positive charge, mak-

ing itpositively charged. When you rub the plastic rod with the fur,

you transfer tiny amounts of negative charge onto the rod and so it has

more negative charge than positive charge on it, making itnegatively

charged.

Water is an example of a substance which is

made of polarised molecules. If a positively

charged rod, comb or balloon is brought

close to a stream of water, the molecules can

rotate so that the negative sides all line up

towards the rod. The stream of water will

then be attracted to the positively charge ob-

ject since opposite charges attract.

Water being attracted to a charged balloon

Photograph by NASA

Chapter 16 | Summary

276 Physics: Electricity and Magnetism