Penny Vs Salt Water Essay

607 Words3 Pages
The purpose of this experiment was to see if a penny could hold more drops of salt water or tap water. It was found that a penny could hold an average of 22.3 drops of tap water and only 20.8 drops of salt water. These results are consistent with the hypothesis: If the salt concentration of water impacts the amount of water a penny holds, then the penny will hold less drops with salt water. While dropping the water onto the penny, it was observed that the water formed into a dome-like shape on the penny. It looked like the individual drops of water turned into one large drop of water. This was observed for both the tap and salt water. This happened due to the cohesion and surface tension of water. Cohesion simply means that water molecules are attracted to each other and want to cling together. Surface tension is the special term that is applied to the cohesion of water molecules. According to USGS, “At the surface, however, there are fewer water molecules to cling to since there is air above (thus, no water molecules). This results in a stronger bond between those molecules that actually do come in contact with one another, and a layer of strongly bonded water. This surface layer (held together by surface tension) creates a considerable barrier between the atmosphere and the water. In fact, other than mercury, water has…show more content…
This hypothesis is based off of the idea of water density and how it changes when a substance is added or removed. A material's density is defined as its mass per unit volume. It is, essentially, a measurement of how tightly matter is crammed together (Jones, 2015). Every matter in the world has its own specific density. Density can be calculated by multiplying the mass times the volume. Water's density can change when a substance is added or when the temperature is increased or decreased with the normal density of water is just under 1 gram per
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