Archimedes Principle with Overflow Can
Brief Description
This demonstration uses an arbitrary object of known volume and an overflow can to show that the volume of a displaced fluid is equal to the volume of a submerged object. A can with a spout near the brim is completely filled with water and a beaker is set under the spout. As an object is submerged into the can, it has to push water out of the way to create space for it. This results in an increase in the water level, which is poured out of the spout and into the beaker. By taking the weight of the displaced water, or the volume displaced, the experimental volume of the object can be determined and compared with its actual volume.
Materials
Overflow can, small beaker, object(s) of known volume, and a digital scale.
Setup
To set up this demo, completely fill the overflow can and allow the water to pour out of the spout until surface tension holds the remaining liquid in; this ensures that the volume poured out of the spout is accurate. Next, determine how the professor wishes to measure the displaced volume in the beaker. If it is to be measured directly, it can simply be read off of the beaker. On the other hand, if it is measured by weight the beaker needs to be tared on the digital scale. The water in the beaker can be weighed and its volume calculated using the density of water value of 0.98 g/cm³.
Performing the Demo
To perform the demo, set the can and beaker next to one another such that the spout is above the beaker. If the surface tension breaks as the overflow can is moved, make sure to repeat the filling process for consistency. Next, slowly submerge the object into the can completely and remove it after the water is done pouring out of the spout. In this case, a steel ball is being used. Now, the displaced water can either be read off of the beaker directly, or by weighing it. If the beaker was tared previously, it can be read off of the scale directly. Otherwise, the weight of the beaker must be subtracted from the total weight. Its volume can then be determined using the density of water. With the experimental volume of the object calculated, it can be compared to the actual volume.
