Resistance is a measure of how hard it is for current to flow.

A metal ion is formed when a metal atom loses one or more electrons and has a positive charge.

Electrons are the charges in conductors that flow to give an electric current.

Two variables are proportional if one changes as a multiple of the other.

Length of a wire

Science

about the properties of electric fields, moving electric charge, and how to analyse series and parallel electrical circuits.

In the Series circuits unit, pupils learnt about static electricity (electric charge), setting up series circuits using circuit diagrams, finding and replacing faulty components, and the rules for electric current and voltage in series circuits.

Resistance and parallel circuits

Physical activity and equipment requiring safe use

Use of equipment that may require supervision for safety, e.g. scissors in KS1, needles, paint, knives, cooking.

Electrons in the wire are attracted by atoms.

Electrons in the wire collide with metal ions.

Electrons in the wire collide with the sides of the wire.

Which of the following statements describes the cause of resistance in metal wires?

The image shown is a representation of the arrangment of the particles in a metal. 
Which of the following particles do the black spheres represent?

A metal wire has a resistance of 6 $$\Omega$$. 
Which of the following resistances is the new resistance of the wire if its length is increased by three times?

Which of the following resistances is the total resistance of the combination of resistors shown?

A current of 0.4 A flows through a resistance cable which is 12 m long. 
What current will flow through 3 m of the same resistance cable?

The resistance increases by a factor of four.

The cross–sectional area of a wire is doubled and the length is halved. 
Which of the following statements describes what will happen to the resistance of the wire?

Which of the following particles are the moving charges in a metal?

Which of the following statements explain what happens if a bare copper wire is folded in half and doubled back on itself? 

One variable changes as a multiple of the other one.

If one variable increases, the other one decreases.

If one variable increases, the other one remains constant.

Both variables stay the same if the other one changes.

Which of the following statements explain what we mean when we say two variables are proportional?

To stop the metal wires touching each other.

Which of the following statements describe the role of the plastic insulation around the copper wires in the cable shown?

The two wires shown are made from the same material. 
Which of the following resistances is the resistance of the thin wire?

A wire with a cross–sectional area of 1 mm$$^2$$ allows a current of 0.2 A to flow through it. 
What current will flow in a wire of the same material with a cross–sectional area of 4 mm$$^2$$?

Content guidance

Risk assessment required - equipment

Adult supervision required

Introduction

What will you need for this lesson?

Are you ready to learn?

Equipment

Content guidance

Supervision

Worksheet