**Specific Gravity of a Solid:**

The specific gravity (SG) of a material is the ratio of its density
to that of water at the same temperature and pressure. The difference between
the weight of a solid in air and under water is equal to the weight of
water displaced by the volume of the sample:

**SG = (weight in air)/(weight in air - weight under water)**

These values are normally reported to only three significant digits.

1. Select water as the liquid and select a solid sample.

2. Tare the balance.

3. Select **sample position** as **weigh in air** and record
the value.

4. Select **sample position **as **weigh under liquid** and record
the value.

5. Click on **change sample**. This gives you a different
sample of the

same material.

6. Repeat steps 2-5 at least twice and calculate values for **SG**.

7. Average your results and estimate the uncertainty of this value.

**Volume of a Solid and Density of a Solid:**

** **All fluids, including air, exert a buoyancy effect. The
weight of a solid immersed in a fluid (**W _{F}**) is related
to the weight in vacuum (

**W _{F}**

The volume may be determined by weighing the solid in two fluids
of known density , such as water (**W _{W}**,

** V = (W _{W}**

Values for the density of water at various temperatures are provided
by the link **density of water**. The density of air may be estimated
at temperature (**t**, ^{o}C) and 1 atm pressure:
**D _{A} = 0.353/(t + 273.15) .**

1. Select **water** as the liquid and select **glass** as the
solid sample.

2. Tare the balance.

3. Select **sample position** as **weigh in air** and record
the value.

4. Select **sample position **as **weigh under liquid** and record
the value.

5. Repeat steps 2-4 at least twice and calculate values for **V**
to four significant digits.

6. Average your results and estimate the uncertainty of this value.

The density of the glass sample can be calculated by correcting the weight in air to the weight in vacuum and dividing by the volume. The densities of other solids may be determined to about ± 0.1% by this method.

**Density of a Liquid:**

After determining the volume of the glass sample (or any other solid),
the densities of other liquids (**D _{L}**) may be determined
by the difference between the weight of the glass sample in air (

1. Select a liquid and select **glass** as the solid sample.

2. Tare the balance.

3. Select **sample position** as **weigh in air** and record
the value.

4. Select **sample position **as **weigh under liquid** and record
the value.

5. Repeat steps 2-4 at least twice and calculate values for **DL**
to four significant digits.

6. Average your results and estimate the uncertainty of this value.

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