# Identify a metal based on its density

The goal of this exercise is for your group to identify the composition of a small metal object. You will make a series of measurements and calculate its density, together with an uncertainty. Then you will use that density to pick several possible materials from a table of metals.

Here are the devices you will have:

• a small metal object of some simple shape
• a scale
• a ruler or meter stick

• measure the dimensions of your object (plus uncertainties)
• measure the mass of your object (plus uncertainty)
• make a neat table of the measurements
• compute the volume of the object, and its uncertainty
• compute the density of the object, and its uncertainty
• find materials in the list of metals which have densities consistent with your measurement
• write down the candidates, and indicate which one(s) you think are the most likely

The following values can be found at The Engineering Toolbox .

```Metal Density (kg per cubic meter)
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Aluminum             2712
Beryllium            1840
Brass                8400 - 8700

Cobolt               8746
Copper               8930
Gold                19320

Iron                 7850
Magnesium            1738

Mercury             13593
Nickel               8800
Platinum            21400

Plutonium           19816
Silver              10490
Steel                7850

Titanium             4500
Uranium             18900