A blank nine-step write-up with the correct table headings. Print it for a real lesson and fill it in by hand. See the specimen lab book
Blank write-up: Resistance
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Study Hack Lab
RP 3 · Physics
Resistance
Write-up template
Name
Date
Course
GCSE Physics
Board and specification
AQA GCSE Physics (8463), 4.2.1.3AQA GCSE Combined Science: Trilogy (8464), 6.2.1.3Apparatus and techniques: AT 1, AT 6, AT 7
Class and teacher
Aim
Find out how the resistance of a wire depends on its length, then measure the resistance of two resistors alone, in series and in parallel.
Contents
Plan and risk assessment
Apparatus
Method
Results
Graph
Analysis
Conclusion and evaluation
Make safe and clear up
A blank write-up for use in a real lesson. The headings follow the AQA required practical; the readings are yours to take. Layout v1, practical v1. Original material; not affiliated with AQA, which has not reviewed it.
1 Plan and risk assessment
Resistance is how hard it is for a current to flow: resistance = potential difference ÷ current. Every centimetre of the same wire adds the same resistance, so a longer wire has more. In series, resistances add; in parallel, the total is less than the smallest.
V = I R
Variables
Independent (you change)
Dependent (you measure)
Control (you keep the same)
Prediction
What will a graph of the resistance of the wire against its length look like?
Resistor A and resistor B are joined in series. What will their total resistance be?
Now A and B are joined in parallel. What will their total resistance be?
Risk assessment
Hazard
Harm it could cause
Control
2 Apparatus
Low-voltage power pack (0–12 V DC) Drives a current round the circuit.
Digital ammeter (multimeter on the 10 A range) (resolution 0.01 A) Measures the current through the wire, in series.
Digital voltmeter (multimeter on the 20 V range) (resolution 0.01 V) Measures the potential difference across the wire, in parallel.
Resistance wire taped to a metre rule (resolution 1 mm) The wire under test; the rule measures its length.
Two crocodile clips One fixed at 0 cm, one moved along the wire to change the length.
Five 4 mm leads Connect the circuit.
Resistors A (6.8 Ω) and B (10 Ω) on holders For the series and parallel part.
3 Method
Write numbered steps someone else could follow. Say what you measure, with which instrument, and how you keep it a fair test.
4 Results
The table is drawn before you measure. Record each reading to the resolution of the instrument, then work out the mean of your repeats, leaving out any anomaly.
Part 1: resistance of the wire · Resistance = mean of V ÷ I for the two readings at each length.
Length in cm
Potential difference in V
Current in A
Repeat potential difference in V
Repeat current in A
Resistance in Ω
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
Part 2: resistors in series and parallel
Resistors
Potential difference in V
Current in A
Resistance in Ω
Resistor A
Resistor B
A and B in series
A and B in parallel
Anomalies
Ring any anomalous result. Say what probably went wrong and whether you repeated it.
5 Graph
Resistance against length · Choose your axes: the independent variable goes on the x-axis. Label each axis with the quantity and unit.
6 Analysis
Resistance of 20 cm of wire
resistance = potential difference ÷ current (V = I R)
Answer
Resistance per metre
Answer
Inside a longer wire
Answer
A and B in series
resistance = potential difference ÷ current (V = I R)
Answer
A and B in parallel
resistance = potential difference ÷ current (V = I R)
Answer
7 Conclusion and evaluation
Conclusion
Conclusion: what do your results show? Use your own numbers.
Sources of error
For each, say whether it is systematic or random, and how it affected your results.
The fixed clip not exactly on 0 cm, and the resistance where the clips touch the wire
The wire heating up while current flows
The ammeter’s resolution (0.01 A) when the current is small
The sliding clip’s contact and exactly where it bites the wire
Improvement
How could you improve the method? Say why it would help.
8 Make safe and clear up
Switch off the power pack and turn it down to 0 V
Let the wire cool before you touch it or the clips
Unplug the leads, unclip the crocodile clips and coil the leads