Experiment 1: Fluid Statics

Introduction: 
In this experiment we estimated the buoyant force using three different methods. Then we compared the results to see which one might have been more accurate.

Equipment:
-Force probe
-String
-Overflow can
-Beaker (to catch overflow)
-Metal cylinders (with hooks or tied with string)
-Meter Stick
-Vernier or micrometer

Procedure:
A) Underwater Weighing Method
We measured the weight of the metal cylinder in the air then while it was completely submerged in water using a force probe and logger pro. The buoyant force can then be calculated by taking the difference of the two resulting string tensions.

B) Displaced Fluid Method
The weight of the beaker used to catch the overflowing water is taken before anything. An overflow can is filled to the top with water and the metal cylinder is placed inside it slowly and carefully. The water will spill into the beaker, when the water stops dripping into the beaker, the mass of both the water and the beaker is measured. By subtracting the mass of the beaker you obtain the mass of the water, by Archimede's principle the weight of this water will be equal to the buoyant force.

C) Volume of Object Method
The volume of the cylinder is approximated and the approximate weight of an equivalent volume of water is calculated from this. By Archimede's principle, this should equal to the buoyant force.

Data/Calculations:
A) Underwater Weighing Method

B) Displaced Fluid Method

C) Volume of Object Method

Summary:
1. Compare your three values for the buoyant force. (treat error analysis and answer the question in terms of uncertainties)
The most accurate answers appear to be the ones where the volume and the displaced water method while the underwater weighing method has a larger error bound. All three methods have their own prominent sources of error. The underwater weighing method does not account for the weight of the string and possible inaccuracies of the force probe. The displaced fluid method can have a few differences in weight measurements. The volume of object method inconsistencies with measurement.

2. Which method do you think was the most accurate and why?
The volume of object method seems to be the most accurate because there is less room for mistakes, whereas in the other two methods we had to rely on a lot more than a few measurements to calculate volume.

3. In part A, if the cylinder had been touching the bottom of the water container, how would that have changed your value for the buoyant force? Would your value have been too low or too high? Explain.
The weight of the metal cylinder would have measured to be significantly smaller underwater and this would have resulted in a higher value for the buoyant force.