Experiment 2: Fluid Dynamics

INTRODUCTION

The laboratory set-up for this fluid dynamics experiment was a bucket filled with water to a height h. A hole was previously drilled onto the bottom of the bucket and taped shut prior to filling it with water. The purpose of this experiment is to conduct a six-trial experiment to test the time it takes to empty a predetermined volume V onto a 300mL beaker, and compare the experimental results with the theoretical calculations based on
t_theoretical = V/(A (2gh)^0.5) to reach the same volume.

DATA

ANALYSIS

The accuracy of the time for the Volume to empty was far off as the theoretical 6.099+/-0.022secs and experimental 12.95+/-0.01secs values did not agree within the acceptable uncertainty. There was a 111.57% error time calculated (secs). The timed data was uniformly precise; therefore it can be assumed that the laboratory set up could be the source of error. One aspect that was noticeable during the experiment was the imperfect perforation of the drain hole and an uneven lesser area than the theoretical diameter calculated area based on diameter.

            With an error in diameter in mind, the experimental drain time data was used to calculate the actual diameter of the hole. The calculation of true diameter resulted in 0.00432m+/0.00001m. Compared with the initial theoretical diameter 0.00630m+/-0.00001m, this resulted in a 31.43% error discrepancy.

CONCLUSION

This fluid dynamics experiment did not result in accurate but precise data. The initial assumption that the diameter was a perfect circle was an error in calculating t_theoretical. Volume empty time did not agree within the uncertainty of either calculation of actual or theoretical. An actual diameter was therefore calculated from the actual experimental pouring time average calculation. The actual diameter was ~31% smaller than the proposed initial diameter and was the error of accuracy related to this lab.  

Experiment 1: Fluid Statics

INTRODUCTION

The lab conducted three fluid statics laboratory experiments. The first part was an underwater weighting method using a hanging buoyant metal cylinder on a string attached to a computer force sensor. Following, part b employed a displaced fluid method in a water filled graduated cylinder, and weighted the over-spilled water in a scale. Lastly, the volume of object method utilized volume calculations to figure out the mass displaced, or otherwise known as the buoyancy force by the metal cylinder.  The purpose of this lab is to find the buoyant force acting on an object three different ways and see how their measurements compare to each other.

DATA

The underwater weight method had a buoyancy of 0.381N+/-0.002N,

followed by the displaced fluid method with a buoyancy of 0.373N+/-0.020N,

and the volume of object method resulted in 0.370N+/-0.035N.

All three of the results are within the acceptable error uncertainty of each other due to the fact that their values overlap in their range.

ANALYSIS

The most accurate method was the underwater weight method because it had the smallest uncertainty calculation. A small uncertainty from the calculations was due to the sensitivity of the computational readings of the hanging force from the tension of the string. This compared to the other two methods, had the best accurate results.

Additionally, if the weight was touching the bottom in part (a), underwater weight method, then the tension of the string hanging would have had a lower than expected downward force, resulting in an incorrect force value and therefore a non-precise buoyancy calculation method.

CONCLUSION

Overall, the fluid statics laboratory was carried out with much success due to the execution and ability to correctly calculate the uncertainties of each calculation method. It follows to say, the least amount of measurements used to reach a desired value, the most precise and accurate that it will be in relation to the true value.