# Buoancy with Pulley and Weights

```Density of Water
Purpose: To determine the density of water using the buoyant
force.
Equipment: Clamp stand, pulley string, masses, metal cylinder.
Theory: Archimedes principle states that the buoyant force on an
object is equal to the weight of the displaced fluid (Fb = mg =
Vg). If an object is completely submerged, the volume of the
displace fluid is equal to the volume of the object.
Hints: Using the pulley, balance your cylinder against a known
amount of hanging mass. Do this twice: when the cylinder is
hanging in air and when it is hanging in water. Do you notice a
difference in the mass you must use to balance the cylinder?
Turn in an individual mini-lab report on loose leaf or graph paper
that includes:
1) A sketch of the experimental apparatus (when the cylinder is
in water).
2) Free body diagram showing all forces on the cylinder when it
is hanging in air.
3) Free body diagram showing all forces on the cylinder when it
is hanging in water.
4) All mass and measurement data collected, clearly labeled.
5) Calculation of the density of water.
6) Percent error, using 1,000 kg/m3 as the standard value for the
density of water.
Purpose: To determine the density of water using the buoyant force..
Theory: Archimedes principle states that the buoyant force on an object is equal to the weight of the
displaced fluid (Fb = mg = Vg). If an object is completely submerged, the volume of the displace fluid is
equal to the volume of the object.
Hints: Using the pulley, balance your cylinder against a known amount of hanging mass. Do this twice:
when the cylinder is hanging in air and when it is hanging in water. Do you notice a difference in the mass
you must use to balance the cylinder?
Turn in an individual mini-lab report on loose leaf or graph paper that includes:
1) A sketch of the experimental apparatus (when the cylinder is in water)
2) Free body diagram showing all forces on the cylinder when it is hanging in air.
3) Free body diagram showing all forces on the cylinder when it is hanging in water.
4) All mass and measurement data collected, clearly labeled.
5) Calculation of the density of water.
6) Percent error, using 1,000 kg/m3 as the standard value for the density of water.
Purpose: To determine the density of water using the buoyant force..
Theory: Archimedes principle states that the buoyant force on an object is equal to the weight of the
displaced fluid (Fb = mg = Vg). If an object is completely submerged, the volume of the displace fluid is
equal to the volume of the object.
Hints: Using the pulley, balance your cylinder against a known amount of hanging mass. Do this twice:
when the cylinder is hanging in air and when it is hanging in water. Do you notice a difference in the mass
you must use to balance the cylinder?
Turn in an individual mini-lab report on loose leaf or graph paper that includes:
1) A sketch of the experimental apparatus (when the cylinder is in water)
2) Free body diagram showing all forces on the cylinder when it is hanging in air.
3) Free body diagram showing all forces on the cylinder when it is hanging in water.
4) All mass and measurement data collected, clearly labeled.
5) Calculation of the density of water.
6) Percent error, using 1,000 kg/m3 as the standard value for the density of water.
```