Theory question about density using Achimedes Principle

[Koscher]

We were conducting a lab experiment in my physics lab. And one of the questions that our TA asked the class was:

If there was a bubble of air trapped in one of your objects, how would it affect the density measurements? Would the density go up, down, or not change at all? Explain.

The experiment was based on Archimedes Principal, and we were looking at the affects of the buoyant force of a fluid, such as water. The objects being used were cubes. One method was density=m/v. The other was with archimedes principle. Density of object = (density of fluid)(mass of object in the air/ (mass of object in air - mass of object when in fluid)). Obviously using the first method the density would be lowered. But i am not so sure about what would happen to the density when using archimedes principle. Any suggestions or ideas would be greatly appreciated.

 

[jbsteele]

If there is a bubble of air trapped in one of your objects, it would affect the density measurements when using Archimedes Principle. The density would go down because the mass of the object that is in the air would be greater than the mass of the object when in the fluid. This is because the air trapped inside the object takes up space, therefore increasing the mass of the object in the air compared to the mass of the object when in the fluid. Therefore, the density would go down because the mass of the object in the air would be greater than the mass of the object when in the fluid.