How to write a scientific lab report

Merita Haxhia

Components of a lab report �  Purpose – What is being studied, independent

variable, dependent variable, constants.

�  Procedure – must be clear for everyone to follow. Materials and apparatus must be included.

�  Data table – well organized

�  Evaluation of data – calculations, graphs, analysis of the graph.

�  Conclusion – what did you find.

Lab – Calculating the free fall acceleration of a wooden block on

Earth

The lab requires finding the experimental value of the free fall acceleration (g) of a wooden block on Earth.

In order to find it, the relationship between the height from which the block will be dropped and the time it takes to reach the ground will be studied.

Lab – Calculating the free fall acceleration of a wooden block on

Earth

�  Purpose – The goal of this experiment is to find the relationship between ______and the ______.

•  IV – time

•  DV – height

•  CV – mass of the block, measurements will be performed near the Earth’s surface.

Lab – Calculating the free fall acceleration of a wooden block on Earth

�  Procedure

It should be written in the way that anyone following your steps should be able to produce the same thing without confusion.

-

-

-

Lab – Calculating the free fall acceleration of a wooden block on Earth

Procedure (continues) Materials:

Apparatus (with labels):

Example Data Table

Time (sec) (+/- 2%)

Height (m) (+/- 2%)

Trial 1 Trial 2 Trial 3 Average

0.2 0.196 0.189 0.195 0.193 0.4 0.726 0.811 0.7848 0.774 0.6 1.692 1.765 1.735 1.731 0.8 3.044 3.139 3.255 3.146 1.0 4.877 4.905 4.935 4.906 1.2 6.988 7.063 7.070 7.040 1.4 9.578 9.633 9.614 9.608 1.6 12.557 12.345 12.440 12.447 1.8 15.892 15.448 15.778 15.706 2.0 19.540 19.488 19.620 19.549

Constants: m = 100 +/- 0.1 gr

Evaluation of Data (Analysis)

A parabolic relationship is noticed. Therefore, a linearization (h vs. t^2) is needed.

Evaluation of Data (Analysis)

Evaluation of Data (Analysis)

Evaluation of Data (cont.)

h = 4.908ms2t2 + (−0.01158)m

slope = 4.908ms2

m =ΔhΔt2

=g2

g = 2m = 2× 4.908 = 9.816 ms2

Δgg=Δhh+2Δtt= 0.02+ 2×0.02 = 0.06

Δg = 0.06×9.816 = 0.589 ms2

g = 9.82± 0.59 ms2

Comparing the equation of the graph with the

equation of the Constant Changing Motion (Free

Fall) of the block dropped from a height,

we have:

Conclusion

The purpose of the experiment was to find the experimental value of the free fall acceleration of

a wooden block. The value is obtained after studying the relationship between the height and the time it takes for the block to reach the floor from that height. The plot of the data collected

showed a parabolic relationship which required a linearization. After graphing height vs. time

squared, the shape of the graph was a straight line and the slope of the line has the units of

acceleration. The value of the acceleration found is g = 9.82 ± 0.59 m/s^2.

Conclusion (cont.)

%error =gexp − gtheorgtheor

×100%=9.816− 9.807

9.807×100%= 0.09%