Lab 1 - Fluid Statics

Fluid Statics

The purpose of this experiment was to find a value for the buoyant force of a mass submerged in water. In or to perform this experiment the following equipment was used :

Force Probe

Overflow Can

Beaker to catch overflow

String 

Metal Cylinders with hooks or tie with string

Meter Stick

Caliper

 Part A:

For the first part an apparatus was set up in order to measure the weight of the metal cylinder using the force probe and logger pro on a laptop and a ring stand after obtaining this value a container of water was then placed in such a way to allow the metal cylinder to float freely in the water. These two values were then used to calculated the buoyant force by taking their difference. Resulting in values:
Fair(weight in air)= 1.1 ±0.24 N
Fwater(weight when submerged) = 0.7189 ± 0.18 N
Fbuoyant = Fair - Fwater = 0.3811 ± 0.202  N

F.B.D. of set-up

Force Probe -Set up

Logger pro +  Laptop a+  lab Pro

Metal Cylinder

Part 2:

For The second method of finding the Buoyant force a beaker's ( a styro foam cup for us) mass is recorded, another container is then placed inside of the beaker. The container within the beaker is filled to the very top. the cylinder is then placed within this container the mass of the overflow of water plus the cup is measured. The mass of the cup is subtracted from the mass of the cup plus water giving the mass of the water. The waters weight should be equal to the buoyant force according to Archimedes' principle. Using this method the recorded mass of the water was, 0.03809 Kg this gives the buoyant force a value of, 0.374 N, which coincides with the value found in part A.

Part B set-up

Part C:

For the final part of the experiment the cylinders volume was calculated by measuring its height and diameter using the equation V= hπr². The volume of water displaced should be equal to the volume of the cylinder, therefore the displaced water's can be theoretically calculated using the volume of the cylinder. This value can then be used to calculate the weight of the water and thus the buoyant force, using the density of water and p(rho) = m/V . using this method the value of the buoyant force for the cylinder 0.3748 N

Summary

In this experiment the values of the three different methods are within 5% error of each other using %error = ((1st value - 2nd value)/average) x 100. Out of the three methods I believe the third was the most accurate. I believe this because the calipers appear to be the more accurate tools used in this experiment. Over all this experiment yielded very solid results. 

Lab question:

If the cylinder had been touching the bottom of the container the value of the buoyant force would have been too high because the cylinder would be acted upon by both the buoyant force and the normal force of the container, and our methods would calculate both forces as one.