# How to Measure the Density of Air

## Determine Volume

• 1). Blow up the balloon with air and tie the neck closed.

• 2). Fill the bucket 3/4 full with water and mark the water level with the pencil on the outside of the bucket.

• 3). Push the balloon into the water so it is completely submerged.

• 4). Mark the new water level with the pencil on the outside of the bucket.

• 5). Measure the distance between the two level marks (h) in centimeters.

• 6). Measure the inner diameter of the bucket in centimeters. Divide the diameter by 2 to get the radius (r).

• 7). Calculate the volume (V) of the displaced water: V = π * r^2 * h. The units of volume are cubic centimeters.

## Determine Mass and Density

• 1). Place the balloon on the balance and record the mass in grams.

• 2). Use the pencil to pop the balloon.

• 3). Place the popped balloon on the balance, and record the mass in grams.

• 4). Subtract the popped balloon mass from the inflated balloon mass. This is the mass of the air that was in the balloon (m).

• 5). Divide the mass of the air in grams by the volume of displaced water in cubic centimeters. This is the density (d) of the air. d = m / V