Mass is important because of two major factors affecting how things move in space: inertia and gravity. The more mass something has, the more of both it experiences. That is why heavy things (things with a lot of mass) are hard to move.

Density is calculated by the dividing the mass by the volume, so that density is measured as units of mass/volume, often g/mL. If both water samples are at the same temperature, their densities should be identical, regardless of the samples’ volume.

The most accurate way to determine an object’s volume, especially in the case of an irregularly shaped object, is to immerse it in water and measure the amount of water it displaces. A graduated cylinder large enough to hold both the object and enough water to fully immerse it is the best tool for this job.

The five steps for determining density can be expressed in simple form as follows: measure the mass of the container, measure the volume of the liquid, measure the combined mass of the liquid and the container, determine the mass of the liquid alone and divide the mass by the volume.

The formula for density is d = M/V, where d is density, M is mass, and V is volume. Density is commonly expressed in units of grams per cubic centimetre. For example, the density of water is 1 gram per cubic centimetre, and Earth’s density is 5.51 grams per cubic centimetre.

The density equation is density equals mass per unit volume or D = M / V. The key to solving for density is to report the proper mass and volume units. If you are asked to give density in different units from the mass and volume, you will need to convert them.

Density is a measure of how heavy something is compared to its size. If an object is more dense than water it will sink when placed in water, and if it is less dense than water it will float.

If an object’s density is less than water’s density (1 g/cm³), it will float. When an object is neutrally buoyant, meaning it neither sinks nor floats, then the weight of the object is equal to the upward buoyant force exerted by the water. When neutrally buoyant in water, the object also has the same density as water.

If the object is denser than water it is more massive than the water that it displaces. This means that the object experiences greater gravitational force than the water and so sinks.

If the buoyant force is less than the object’s weight, the object will sink. The buoyant force is always present whether the object floats, sinks, or is suspended in a fluid. Archimedes’ principle states that the buoyant force on an object equals the weight of the fluid it displaces.

1. 1) Find the density of the object.
2. The density of the object is the mass of the object divided by the volume of the object.
3. 2) Divide density of object by the density of the liquid and express as a % to get % submerged.
4. For floating in water of density 1.0 gm/cm^3, dividing yields 0.8 or 80% of the object is submerged.

The buoyant force on a submerged object is equal to the weight of the fluid displaced. This principle is useful for determining the volume and therefore the density of an irregularly shaped object by measuring its mass in air and its effective mass when submerged in water (density = 1 gram per cubic centimeter).

Sea water on the other hand is more dense since it has salts, therefore we shall use Rhow = 1.035 g/cm3 (or 1035 kg/m3). So, the fraction of ice underwater, Vw/Vi, is given by the ratio of densities Rhoi/Rhow=0.87. Over 87% of an iceberg’s volume (and mass) is underwater.

Density also explains why most of an iceberg is found beneath the ocean’s surface. Because the densities of ice and sea water are so close in value, the ice floats “low” in the water. This means that ice has nine-tenths, or 90 percent of water’s density – and so 90 percent of the iceberg is below the water’s surface.