Lab Report Structure
1. Aim & objectives of the experiment
Explain the aim & objectives of the experiment.
2. Introduction
Mention the experiment.
Explain the principle of the experiment.
3. Equipment used
List the equipment you used.
4. Safety
Did you consider any safety issues while carrying out the
experiment? Explain.
5. Method
Provide any ray diagrams or diagrams that you used.
Explain the formula and terms used with appropriate units.
Explain the procedure.
6. Results
Include the tables.
Attach the relevant graphs.
Show the working for each type of calculation.
7. Uncertainties
Explain the uncertainty involved in the experiment.
Error analysis should be provided here.
8. Discussion
Discuss your result
Relate your findings to the theory.
What result did you expect? What did you get? If you got
unexpected result what went wrong? How it could have been
rectified.
9. Conclusion
Give your conclusions.
10.References & Bibliography
List the references you used (books, websites etc.). Harvard
referencing should be used. Don’t forget the citation. Also, include
all the other sources consulted, even if not directly cited in the
report.
Note:
Read your report and use spell check.
Do not cut and paste from websites.
Don’t forget to provide references
About this experiment：
Experiment 1: Diffraction Grating.
Caution. Follow the specific instructions you are given about working safely with laser
light.
You are provided with a laser light source, and two diffraction gratings. One grating has
known line spacing. Task 1 is to use the grating with the known spacing to determine
the wavelength of the laser light. Task 2 is to work out the spacing on the unknown
grating, using the value of λ found in task 1.
For a diffraction grating nλ = dsinθn
where n is the order of the maximum,
λ is the wavelength,
d is the slit spacing of the grating and
θn is the angle between the direction of the central beam and the direction of the
nth maximum.
Task 1
1. Set up the apparatus to produce an interference pattern on the screen.
2. Draw a labelled sketch of your experiment.
3. Indicate, by labels or explanation, how you will obtain n, d, and θn for each
maximum you investigate
4. List the measurements required.
5. Draw a suitable table for your results.
Include quantities, units and uncertainties in the table headings.
6. Take measurements and record them in the table
7. Plot a suitable graph and use the gradient to find λ.
To find the wavelength of the light
n X (unit) tanθ = x/y θ(unit) sinθ
1 1.4cm 0.035 2.004 0.035
2 2.6cm 0.065 3.719 0.065
3 3.9cm 0.097 5.540 0.096
4 5.2cm 0.13 7.407 0.129
5 6.5cm 0.16 9.090 0.158
8
n is the order
y is the distance between the grating and screen
x is the distance between the central maximum and nth maximum
λ = d sinθ /n
{sinθ/n is obtained from the graph}