unlike charges attract

like charges repel

Describe and interpret simple experiments to show the production and detection of electrostatic charges by friction

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 charging a body involves the addition or removal of electrons.

- Grounding is the process of removing the excess charge on an object by means of the transfer of electrons between it and another object of substantial size.

- 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.

- Current is the flow of charge (electrons) within a circuit.

- State that current in metals is due to a flow of electrons

- Resistance is directly proportional to length

- Resistance is inversely proportional to cross-sectional area

inversely proportional- the two quantities behave opposite in nature.

parallel circuit

- sum of currents in the separate branches = current from source

- total circuit resistance = 1/R1 + 1/R2 + 1/R3

- current from source > current in each branch

- the lower the resistance, the higher the current.

- combined resistance of two resistors

- voltage across all the components is the same in a parallel circuit

- I = Q / t

current = electric charge / time

amperes [A] = coulombs [C] / time [s]

- R = V / I

Resistance = voltage / current

Increasing the resistance will cause the current to decrease.

- I = P / V

current = electric power / potential difference

- E = IVt

energy = current x voltage x time

- Recall and use the fact that the sum of the p.d.s across the components in a series circuit is equal to the total p.d. across the supply

p.d. = resistance

- Calculate the combined resistance of two resistors in parallel