Outcomes

Pupils can use the equation: Q = I × t
Pupils can identify the direction of movement of charge in a wire, charge in an elecrolyte and the direction of flow of conventional current

Specification References

2.15 understand that current is the rate of flow of charge

2.16 recall and use the relationship between charge, current and time : charge = current × time

2.17 recall that electric current in solid metallic conductors is a flow of negatively charged electrons

Demonstrate potassium permanganate in amonia on filter paper, resting on a slide in an electric field. Alternatively view the movement of ions.

Class Practical: Electrolysis

Use this worksheet to plan an experiment to investigate the variables that affect the rate of completely coating a 10p coin with copper - we are concentrating on how voltage affects the rate.
The pupils make a detailed prediction as to which terminal the 10p should be placed and what the other variables should be set at in order to achieve the quickest coating.
The pupils observe the coin being coated. After a fixed time interval, maybe 4 minutes, the pupils remove the coin, dry it and reweigh it to find the mass of copper transferred. This is done for a range of voltages. The resulting data shows how increasing the voltage (and therefore the current) affects the mass of copper added; therefore the movement of copper ions. * In conclusion, the pupils should link increasing the 'voltage' to an increase in current when all other variables are kept constant. Furthermore, they should start to link voltage to the work done (energy) to coat the coin. Indeed if the voltage is increased then the ions are given more energy, move faster and the coin is coated more rapidly.

Class act as charges in a circuit. Which way would they move if they were i) positive ii) negative? What happens in a solid and a liquid?

To read pages 176-180 in Complete Physics and to write an analogy for current, voltage and resistance in a series circuit.