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- Describe and interpret simple experiments to show the production and detection of electrostatic charges.
Electrostatic attraction can be produced and observed in a simple experiments:
- Inflate a balloon and rub it quickly on any dry surface e.g. a carpet. Then open a tap and hold the balloon next to it (without touching the water). You should see that the water bends towards the balloon!
- Tear up a piece of paper into small bits. Then take a ruler, rub it on your hair and place them just above the bits of paper, without touching them. You should see the paper get attracted to the ruler.
This kind of attraction is called electrostatic attraction. This happens because of the charges on the materials.
- State that there are positive and negative charges.
Since all materials on earth are made up of atoms which contain the positively charges protons and negatively charged electrons, any imbalance in the number of protons and electrons will cause the material to be charged or ionised. A loss of electrons will make it positively charged and a gain of electrons will make it negatively charged.
When you rub the balloon, for example on the carpet, electrons (with a negative charge) build up on the surface of the balloon (they are transferred from the carpet to the balloon). This is called static electricity, which means “non-moving electricity”.
- Describe an electric field as a region in which an electric charge experiences a force.
Just like how magnets have magnetic fields around them, electricity carrying wires have electric fields around them. They are created when an electrically charged object is placed near another charged object.
- State that unlike charges attract and that like charges repel.
Yep, just like magnetic poles, electric charges also attract when they’re unlike and repel when they’re like.
The electrons in the balloon above, have the power to pull very light objects (with a positive charge) toward them – like the positive ions in the water.
- Distinguish between electrical conductors and insulators, and give typical examples.
Conductors are materials in which current can flow. Examples: copper, aluminum, gold and silver.
Insulators cannot conduct electricity. Examples: glass, wood, paper, air and rubber.
Notes submitted by Lintha
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