Place the object on an accurate scale and record the mass in your notebook. Alternatively, you can measure mass by using a balance. Place your object on one side and place weights of known mass on the other side until both sides are balanced. The total mass of the balance weights is equal to the mass of your object. Make sure object is dry so that absorbed water does not affect the accuracy of the weighing.
Measure the length and radius if it is a cylinder or length, width, and depth if it is a rectangle. Record your dimensions in millimeters or centimeters. Calculate volume using the formula for the shape of your object. For example, volume of a cylinder is length times pi times radius squared, while the volume of a rectangle is the product of length width and depth. Units of volume are centimeters cubed.
Fill a graduated cylinder with enough water to completely submerge the object, but not overflow. Record the water level of the beaker. Gently place the object in the beaker ensuring that it is fully submerged. Record the new water level of the beaker. Subtract the new water level from the starting water level. This is the volume of the object in cubic centimeters. Liquids are generally measured in milliliters however one milliliter is equal to one cubic centimeter. [1] X Research source
Density=Mass/Volume{\displaystyle Density=Mass/Volume}
Place your object in the different liquids to see if it sinks or floats.
Drop your object in a fluid of known density. If it sinks, try putting it in a different fluid that is more dense. If it floats, put it in a fluid that is less dense.
When your object floats within the fluid, you have found the approximate density of the object.
