# 4.2.1.2

Electrical charge and current

# 4.2.1.2 Electrical charge and current

## Content

• For electrical charge to flow through a closed circuit the circuit must include a source of potential difference.

Electric current is a flow of electrical charge. The size of the electric current is the rate of flow of electrical charge. Charge flow, current and time are linked by the equation:

charge flow = current × time

Q =It

charge flow, Q, in coulombs, C

current, I, in amperes, A (amp is acceptable for ampere)

time, t, in seconds, s

A current has the same value at any point in a single closed loop.

MS 3b Change the subject of an equation

MS 3c Substitute numerical values into algebraic equations using appropriate units for physical quantities

# Resources

Charge Foundation

Charge Higher

# Videos

gAgTtZHW5tuemtEy.mp4

Static hair

videoplayback.mp4

LIGHTENING strike

TraVOLTa.mp4

John Travolta

My Movie.mp4

Static electricity

## Practicals

### Practical

Demo :

• Balloon to blow up to explain static electricity - show it sticking to the wall
• Use the tesla coil to show a "field" lighing up neons.
• Vandaar graaf
• Bubbles
• 2x Foil with leads (croc clips)

Practical:

11 x collection of cloth and plastic rulers

11 x coke cans for racing.

### Risk

Risk:

• Warn students of posibility of a small shock