Christina Svensson Mr. Porter

SCH3UE- 03Partners: Sonya Minhas and Kinsey Beck

September 23rd 2008

Design lab: The thickness of an Aluminium sheet

Purpose: The purpose of this experiment is to determine the thickness of a sheet of Aluminium foil. By using a set of data and deriving known equations, we will find a way of determining the thickness of the foil.

Materials: Three rectangular sheets of Aluminium foil (approximately the same size) Centimetre ruler Calculator Electronic Balance

Procedure: 1. Make a table (of which you are to put in the info)2. Measure the piece of aluminium foil (mass, length and width). Record your

measurements (mass, length, width and density) and put in data table 1.3. Trade your piece of aluminium foil with another group and repeat until you have data

on three pieces. Repeat step 2.4. Use this info to determine volume, area and thickness of the Aluminium foil sheet

Data table 1:Al. foil sheet #:

Mass(g) ±0.01g

Length(cm) ±0.05 cm

Width(cm)±0.05

Density(g/cm3)± 0,01 g/cm3

Thickness (cm)

2 0,51 ± 1,96 % 12,8 ± 0,39 % 10,0 ± 0,50 % 2,70 ± 0,37 % 0,0014± 0,0045 3,2 %

8 0,70 ± 1,42 % 17,5 ± 0,29 % 9,8 ± 0,51 % 2,70 ± 0,37 % 0,00106± 0,0036 3,4 %

7 0,52 ± 1,92 % 12,9 ± 0,39 % 9,9 ± 0,51 % 2,70 ± 0,37 % 0,0014± 0,0045 3,2 %

Sample calculations: Aluminium sheet #2:

Uncertainty of Mass:= (0.01/0.51g) X 100= 1.96%

Uncertainty of Length:= (0.05/12.8) X 100= 0.39%

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Uncertainty of Width:= (0.05/10.0) X 100= 0.50%

Uncertainty of thickness:Mass: 1,96 %Length: 0,39 %Width: 0,50 %Density: 0,37 %…and than the thickness uncertainty is:

= ± (1,96 %+ 0,39 %+ 0,50 %+ 0,37 %)= ± 3,22

…that means that the thickness equals to:

= 0,0322x 0,0014= 0,0045

Conclusion/Evaluation:This experiment demonstrated the purpose (hypothesis) of that we can have a given set of data, and by rewriting the equations, solve for T (thickness). As you can see in the sample calculations, all we did was to rewrite the equations, and solve for “x”.

We were able to determine the thickness of the Al. foil sheet, but there is several uncertainties to these measurements. Nr 1; aluminium foil is wrapped in aluminium oxide, to prevent radioactivity, which have a different density than aluminium itself. This would have an impact on the lab, but it would be a continuously error, which means that your way of calculating will be right, just not the answer. The impurity of the sample might also have an impact on the result (the writing, dirt, etc).There are also several factors that make the weight an uncertain measurement tool. Someone breathing, etc, can have an impact on the measurement results. This would also be a continuously error. But if there is something wrong with the weight itself, it is no longer a human error; it is a systematic error.

What we could do to make this experiment even better is to isolate the air around the weight(no movement), have a more exact weight, used pure aluminium(or have a different density), not write on the sample and keep it pure.

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