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: Force and extension
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Study Hack Lab
RP 6 · Physics
Force and extension
Write-up template
Name
Date
Course
GCSE Physics
Board and specification
AQA GCSE Physics (8463), 4.5.3AQA GCSE Combined Science: Trilogy (8464), 6.5.3Apparatus and techniques: AT 1, AT 2
Class and teacher
Aim
Investigate the relationship between force and extension for a spring, and use it to find the spring constant.
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 v2. Original material; not affiliated with AQA, which has not reviewed it.
1 Plan and risk assessment
Hooke’s law: up to the limit of proportionality, the extension of a spring is directly proportional to the force on it. The spring constant k is the force needed per metre of extension, so a stiffer spring has a bigger k.
F = k e
Variables
Independent (you change)
Dependent (you measure)
Control (you keep the same)
Prediction
What will happen to the extension as you add more force?
A second spring is stiffer: it has a bigger spring constant. You hang the same masses on it. What happens to its extensions?
You take the masses off again, one at a time. If the spring has not been overstretched, where will the pointer be when every mass is off?
Risk assessment
Hazard
Harm it could cause
Control
2 Apparatus
Clamp stand with two bosses and clamps Holds the spring and the metre rule.
Spring The object being stretched.
Metre rule (resolution 1 mm) Measures the position of the pointer.
Pointer (splint or wire) Marks the bottom of the spring against the scale.
100 g mass hanger Carries the masses; counts as the first 100 g.
100 g slotted masses (×7) Each adds 0.98 N of weight.
G-clamp or heavy weight Stops the stand toppling.
Eye protection In case the spring snaps or springs off the hook.
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.
Force and extension · Extension = pointer reading − pointer reading with no masses.
Force in N
Pointer reading in cm
Extension in cm
0.00
0.98
1.96
2.94
3.92
4.90
5.88
6.86
7.84
Anomalies
Ring any anomalous result. Say what probably went wrong and whether you repeated it.
5 Graph
Force–extension graph · Choose your axes: the independent variable goes on the x-axis. Label each axis with the quantity and unit.
6 Analysis
Extension
extension = pointer reading − pointer reading with no masses
Answer
Gradient (extension per newton)
Answer
Spring constant
F = k e, so k = F ÷ e = 1 ÷ gradient (with e in m)
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.
Parallax when reading the pointer
Reading before the spring stops bouncing
Zero error in the unloaded reading
Slotted masses not exactly 100 g
Improvement
How could you improve the method? Say why it would help.
8 Make safe and clear up
Take the masses off one at a time, keeping feet clear
Unclamp the spring and the metre rule and put them away