Lab Partners: Max McCandless and Vincent Mele
Date of Completion: May 30th
Date of Completion: May 30th
Purpose
The purpose of this lab is to investigate Archimedes' Principle.
Theory
Archimedes' Principle states that the buoyant force of an object is equal to the weight of the water that the object displaces. In addition to this, apparent weight, or the weight an object seems to have when submerged in a fluid, is equal to the actual weight minus the buoyant force.
Note: in the second equation shown below, the density of the fluid times the volume that the object displaces is substituted in the place of the mass of the displaced fluid. |
Experimental technique
1. Derive an equation that can be used to solve for the density of a fluid using information gained from putting an object in it. (See: Theory)
2. Mass the object in the air.
3. Tie a string through the object and set the balance to use the hook rather than the surface.
4. Put one of the four fluids in a beaker, put the beaker on the balance, and hang the object on the hook in a fashion so that it is submerged in the fluid but does not touch any of the sides of the beaker.
5. Record the apparent mass.
6. Repeat this process with two more of the fluids.
7. Adjust the balance so it works with the surface rather than the hook once more.
8. Zero the balance with a beaker on it.
9. Pour some of one fluid in the beaker, and record the mass and volume the fluid takes up.
10. Repeat with the other two liquids used previously.
11. Find the volume of the object by dropping it in the fluid and seeing how much the volume changes (only do this once)
12. Calculate density, and compare the results to those found using the first method.
2. Mass the object in the air.
3. Tie a string through the object and set the balance to use the hook rather than the surface.
4. Put one of the four fluids in a beaker, put the beaker on the balance, and hang the object on the hook in a fashion so that it is submerged in the fluid but does not touch any of the sides of the beaker.
5. Record the apparent mass.
6. Repeat this process with two more of the fluids.
7. Adjust the balance so it works with the surface rather than the hook once more.
8. Zero the balance with a beaker on it.
9. Pour some of one fluid in the beaker, and record the mass and volume the fluid takes up.
10. Repeat with the other two liquids used previously.
11. Find the volume of the object by dropping it in the fluid and seeing how much the volume changes (only do this once)
12. Calculate density, and compare the results to those found using the first method.
Data
Analysis
Conclusion
In this lab, Archimedes' Principle was investigated. Using the idea that the buoyant force of an object is equal to the weight of the fluid displaced by the object, the density of the fluid the object is submerged in can be calculated. This information is confirmed when this calculated density is compared to the density calculated by simply taking the mass of the fluid divided by the volume. These results yield a very low percent difference, and from this information it can be concluded that the values are nearly the same. This information confirms Archimedes' Principle, and its value in practical situations.
Some possible sources of error are the measuring equipment, as some of the values are likely to be slightly inaccurate due to the fact that no piece of measuring equipment is perfectly accurate. Also, the weight of the string does have a slight effect on the apparent masses found when the object was submerged in the fluids. The string's mass is only nearly negligible.
Some possible sources of error are the measuring equipment, as some of the values are likely to be slightly inaccurate due to the fact that no piece of measuring equipment is perfectly accurate. Also, the weight of the string does have a slight effect on the apparent masses found when the object was submerged in the fluids. The string's mass is only nearly negligible.
References
The Physics Classroom.com. Retrieved on May 30th, 2014, from http://www.physicsclassroom.com