Aluminum foil, an everyday item used to keep food safe in the kitchen, is possibly the thinnest material in your home. Manufacturers of aluminum foil often provide the width and length of the foil roll on the package, but the thickness of the foil is often not advertised or displayed. Instead, it's common to see labels like "standard duty," "heavy duty" and "extra heavy duty" to describe foil thickness. It is difficult, but not impossible, to measure the thickness of such a thin material, and impossible to do with common measuring tools, like a ruler or a measuring tape.
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Measure the thickness of aluminum foil with a precision measuring tool called a micrometer, but if you don't have access to a micrometer, you can use another, indirect means of measurement. This involves one or more mathematical formulas. The values needed to measure the thickness of aluminum foil are the length, width and weight of the sample and the known density of aluminum, which is 2.7 g/cm3.
Use a ruler to measure the length and width of the aluminum foil in centimeters. Crumple the piece of foil into a small ball or fold it into a small shape and place it on a milligram balance to find the weight. Records the values on a sheet of paper or data table.
Remind yourself of the relationships density = mass ÷ volume and volume = length x width x height. When working out the thickness of aluminum foil, you are simply working out its height dimension. This simple formula allows you to measure the thickness of aluminum foil.
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Use the formula mass of foil ÷ (length of foil x width of foil x density of aluminum) to find the thickness of aluminum foil. The density of aluminum is 2.7 g/cm3. So if you have a piece of aluminum foil that is 15 cm long and 20 cm wide and weighs 1.8 g, the calculation is 1.8 ÷ (15 x 20 x 2.7). The answer is 0.00222 cm, or 2.52 x 10-3 cm.
Convert the thickness into inches if you desire to by multiplying the answer in cm by 0.39370, because 1 cm is equivalent to 0.39370 inches. In the example above, you would work out 0.00222 x 0.39370, which is 0.000874 inches, or 8.74 x 10-4 inches.