Effect of Salt on Cooling of Water

[Topf]

Homework Statement

How does the average rate of cooling relate to saturation of salt in water?

Variable: salt, water, surface area of pot/container, initial temp

The Attempt at a Solution

So, to do this lab I started out with saturated water, and then got progressively less saturated when taking the tests. The beginning temperature was 100° C and then I recorded the temperature every 30 seconds (after I stopped the heat). With this data I thought the relationship was linear, that is the less salt the faster water will cool. Now my question is, is this truly the case, and if anyone could refer me to a sources, as for my conclusion I must cite at least two opinions of physicists/books/anything on the matter.

 

[jbsteele]

The average rate of cooling for the water is related to the saturation of salt in the water. As the concentration of salt decreases, the rate of cooling increases. This is because the lower salt concentrations allow more heat to escape from the water, resulting in faster cooling. Additionally, the surface area of the pot or container and the initial temperature of the water also play a role in the rate of cooling. A larger surface area allows more heat to escape, while a higher initial temperature will result in a faster cooling process. Sources that support this conclusion include: 1)The American Physical Society's Physics Education Research Group (PERG): "The rate of cooling of a liquid is affected by the amount of salt dissolved in it. The more salt, the slower the cooling rate." 2)Lecron, L. (1956). Physics and Technology for Future Presidents. New York, NY: W.H. Freeman and Company. The author states, "In general, the rate of cooling is slower when there is more salt in the water, since the salt molecules absorb energy and release it more slowly than pure water molecules."