Density of an object that floats.

[qwertysaur]

No, it is a structured lab. Were are comparing wood from four different species of tree, and then we get a sample from an unknown tree and must find which tree it is the most similar to. Then the botany half I was told that they will investigate why specific traits developed, and which known sample was the closest to the unknown, and then they create a cladogram with the five wood samples.

[Woodinator]

Well if you want to know how much water is abosrbed by the wood, take the mass before it is submerged and after...subtract the masses and you have the mass of water and then since at standart temp and pressure pure water is 1g/ ml you could multiply that out to find ml of water in the wood...

If i were you though, I'd just do simple water displacement though, you're looking at small error values that are inevitable any way you do it, you're probably just over-thinking :P

[Chemical]

I remember doing this...

MASS:
When an object floats, the mass of the water it displaces is equal to its own mass.
Note: The density of water is 1 g/cm3.

Mass of Water
= D x V
=1 g/cm3 x Volume displaced (1mL = 1 cm3)
= Mass of object


VOLUME:
When an object SINKS, the volume of the water it displaces is equal to its own volume. (When two objects are equal in size, this is also the volume of the object that floats)

You have M and V, substitute to find D