1. Learning Objective Describe and calculate current and charge
To be able to:
Describe and calculate current and charge
Key Words:
Current, charge, electrons, flow

2. What are the symbols? Sunday, 26 May 2019 Current and Charge
Date and title in books. You need a pen, pencil & ruler.
Starter Activity – 5 minutes
What are the symbols?

3. Rearrange the equation to calculate current and time
(F)
Target 9-1
Identify what is meant by current and charge
(F/H)
Target 4-9
State and use the equation to calculate charge
(H)
Target 5-9
Rearrange the equation to calculate current and time
Extension: Application of Knowledge
Target 8/9
Explain the flow of current in a circuit in terms of electrons
Learning Outcomes

4. What is current?
Current is a measure of the rate of flow of electric charge in a circuit. Electric charge is measured in coulombs.
How is current measured? A
An ammeter must be connected in series as it measures the current flowing through it.
Current is measured in amperes (A) using an ammeter.
A current of 1 A is 1 coulomb of charge flowing every second.
So, a current of 5 A is 5 coulombs of charge flowing every second.
Teacher notes
It may help some students to conceptualize the idea of electrons moving around a circuit by introducing the idea of electron drift velocity. This is a measure of how much electrons move in a material. For example, when a 1 ampere current travels through a copper wire with a 1mm2 cross section, the drift velocity is less than 0.1 mm per second.
More information about drift velocity is available at

5. What is conventional current?
Before the discovery of the electron, scientists assumed that current was due to positively-charged particles moving from the positive terminal around a circuit to the negative terminal.
This way of representing the direction of current is called conventional current.
It is now know that charge is carried by electrons, flowing from the negative terminal to the positive terminal. This is called electron flow.
Today, both conventional current and electron flow can be used to represent the direction of current.

6. How to calculate Charge
Boardworks GCSE Additional Science: Physics
Resistance and Resistors
How to calculate Charge
The Current in a circuit can be seen as the rate of flow of charge. We can calculate the current flowing through a wire if we know how much coulombs flows in a given amount of time. Alternatively we can calculate the Charge if we know how long a current flows for:
Q = I x t
Where:
Q = Charge (C)
I = Current (A)
t = Time (s)
Teacher notes
This slide could be used with higher ability students to help improve their understanding of the subject matter.

7. Current and Charge Electric current is a flow of electrical charge.
The size of the electric current is the rate of flow of electrical charge