Finding the volume of an odd-shaped solid object that floats, requires a few simple steps.
The Displacement Method (Archimedes Principle) provides an easy way of measuring the Volume of an odd-shaped object that floats.
Remember that Volume = Length x Width x Height or L x W x H. This refers to the amount of space that is taken up by the fluid or solid object.
Cubic Units of Volume (1cm³) are used to measure the volume of solids.
Capacity Units of Volume (1ml) are used to measure the volume of fluids.
1cm³ = 1ml.
You can easily switch from one type of unit to the other. For example, if you have a container that measures 5 x 5 x 5, you know that it can hold 125 ml of water.
Step 1) Set up the measurement tool (measuring cup, graduated cylinder, etc.) by filling it with water to a level that will accommodate the objects.
Step 2) Find and measure the volume of a weight that you can anchor to the floating object to make both objects sink.
Step 3) Once you determine the volume of the weight that you will attach to the odd-shaped object, you can proceed as you would normally, using the displacement method. The only difference being, that you will subtract the volume of the weight that you have used to sink both objects from the original Water Displacement Level.
Observations:
When you submerge both objects in the water, the water level will rise to a certain height. We can call this the Water Displacement Level (WDL).
Then you can subtract the volume of the known object from the measurement of the Water Displacement Level. (WDL)
This leaves you with the original Water Level Baseline (WLB), plus the left-over amount of displaced water from the unknown odd-shaped object that floats.
You must then subtract the original Water Level Baseline from that measurement, to obtain the Volume for the odd-shaped object.
The formula is as follows:
Water Level Baseline = WLB
Water Displacement Level = WDL
Irregular Shaped Object = ISO1
Known Volume Object = KVO2
WLB + ISO1 + KVO2 = WDL
WDL – KVO2 = WDL for ISO1
WDL for ISO1 – WLB = Total Volume of Odd-Shaped Object