Cooling Rate of Water 9-20-09 This week’s lab attempted to investigate cooling rate of water. Heat is the total energy of all particles in a substance. Cooling Rate is the rate at which temperature decreases with time. The three variables tested in this lab were the amount of surface area that touched the air, the container material, and crushed or whole ice. The first hypothesis stated that the water in the small beaker would cool off faster for an unknown reason.
The second hypothesis stated the hot water would cool faster in a foam container, because the foam is an insulator, which doesn’t let heat in. The third hypothesis stated that the whole ice would cool a liquid faster because the crushed ice will melt faster. The first conclusion was the larger beaker cools of faster because there is more surface area to cool off the water. The second conclusion was the foam cup cooled off slower because foam is an insulator so it traps the heat in, and glass is a conductor so it releases heat.
The third conclusion was crushed ice cooled the liquid faster than the whole ice because the crushed ice covers more surface area. All of the hypotheses were incorrect. In the first lab, the water wasn’t poured in the beaker at the same time and the initial temperature was not the same in both beakers. In the second lab, there was more water in the foam container than in the glass container. In the third lab, once again, the initial temperature was not the same in both beakers.
The relationship between cooling rate and beaker size is the larger the beaker the faster it will cool because there is more surface area to cool the water. The relationship between cooling rate and beaker material is glass cools off water faster because glass is a conductor, which releases heat, and foam is an insulator, which traps heat. The relationship between cooling rate and type of ice is crushed ice cools of liquids faster because it covers more surface area than whole ice.