# How to Calculate the Volume of Voids

Save

A void is the volume of space in a material such as sand or gravel not occupied by particles. The volume of voids is made up of tiny gaps between particles of the material. Calculating the volume of voids can be complex, requiring high-tech tools such as measuring lasers. In other situations, like the one described here, calculating the volume of voids is fairly simple. You have to first determine the specific gravity of the material in question. Specific gravity is the ratio of the density of a substance to the density of water (equal to 1 g/ml).

### Things You'll Need

• Precision scale
• Water
• Sand or other material
• Calculator
• Straightedge
• Fill a 1,000 ml graduated container about half full of water. Weigh the container using a scale calibrated in grams. Record the weight and the exact volume of water in the container.

• Add enough sand to bring the overall level in the container to about 3/4 full. Weigh the container again and record the weight and the volume of material now in the container.

• Subtract the original weight (water only) from the weight of sand plus water to find the increase in weight. Subtract the original water volume from the volume of sand plus water to find the increase in volume.

• Divide the increase in weight by the increase in volume to find the specific gravity of the sand. For example, if the weight of sand plus water was 450 g more than of the water alone and the volume increase was 180 ml, you have a specific gravity of 450/180 = 2.5.

• Empty and dry the container thoroughly. Weigh the empty container. Fill the container to the 1,000 ml mark with dray sand. Use a straightedge to smooth the surface of the sand so it is level.

• Weigh the container of sand and subtract the weight of the empty container to find the weight of the sand. Divide the weight by the volume (1,000 ml) to find the density of the sand. For example, if the sand weighs 1,500 grams, the density is 1.5.

• Subtract the density of the sand from the specific gravity of the sand, then divide the result by the specific gravity to find the voidage (proportion of empty space in the dry sand). For example, with a density for dry sand of 1.5 and a specific gravity of 2.5, you have a voidage of (2.5 – 1.5)/2.5 = 0.4.

• ### Other People Are Reading

• Multiply the voidage by the volume of the dry sand to find the volume of the void. With 1,000 ml of dry sand and a voidage of 0.4, you have a void volume of 400 ml.

## References

• Photo Credit Jupiterimages/Pixland/Getty Images
Promoted By Zergnet

### You May Also Like

• Void Ratio for Common Gravel & Sand

In soil mechanics, the void ratio describes the relationship between the volume of voids, or spaces, in the soil or aggregate to...

• How to Calculate Volume

You can calculate volume with an easy to use formula. The standard shapes such as a square or rectangle all use the...

• How to Calculate Porosity

Porosity refers to the amount of void (or open space) within a volume of sediment. The value of porosity is measured as...

• How to Calculate V/V (Volume / Volume)

The term v/v, or volume/volume, describes the concentration of a solution. Students learn this concept in high school and lower-level college chemistry...

• How to Calculate Backfill

Backfill is used to replace soil or dirt that was excavated from the ground. This can include a garden site for raised...

• How to Calculate Voidage

Voidage is the proportion of unoccupied volume (that is, gaps or empty spaces) in a volume of some material. The term voidage...

• How to Calculate Specific Volume From Specific Gravity

The inverse operation relates specific gravity and specific volume. Specific gravity refers to the mass &#8212; or density &#8212; of a sample...

• How to Calculate Void Ratio

Oceanic production sites that extract and distribute oil-based products require certifications to perform these activities and analyses of the ocean's floor and...

• What Is Soil Porosity?

Porosity is the open space between soil grains. Soil scientists use porosity measurements to determine how effectively air and water move through...

• Size & Type of Gravel for a French Drain

A French drain offers a gravity-assisted means of keeping the yard free from excess moisture. While several sizes and types of gravel...

## Related Searches

Check It Out

### Can You Take Advantage Of Student Loan Forgiveness?

M
Is DIY in your DNA? Become part of our maker community.