# AP Physics Lab: Density of a Solid by Under Water

```AP Physics Lab: FLUIDS - Density of a Solid by Under Water Weighing
Names _______________________ Class__________Date______ _Row____
Purpose: To determine the density of an unknown metal by under-water weighing,
based on the physics of buoyancy.
Background: When the mass of a solid object is known, as well as the density of a
liquid in which the solid can be submerged, it is possible to calculate the unknown solid
object density from a measurement of its weight un-submerged and when fully
submerged in the liquid.
Challenge: Devise an experiment to do the above, using the materials presented to you,
a container for the water, samples of the metal of known mass, and a force sensor.
Write the steps of the experiment you will do:
Derive an equation for the unknown density in terms of the liquid density, metal mass or
weight, and the underwater weight.
Make a table of your data including description of metal: (all groups may not have same
metal: what is shape, color etc)
Calculate your result: ______________________ (measured density in Kg/m3 )
Write a brief description of the problems you encountered when performing the
measurements. Finally make an educated guess (possibly based on book or Internet