Homework 1/18/11 Water Freezing

Room Temp	Freezing Point Temp	Salt Amount	Time	Time	Inches (height) Before	Inches (height) After
20°C	-7°C	3tsp	8:30  20°C 9:00 13°C 9:15  10°C 9:30   6°C	10:00  6°C 10:15  6°C 10:45  6°C 12:45  -7°C	2in	2.45in
20°C	-4°C	1 ½ tsp	8:30 20 °C 9:00 11°C 9:15  4°C 9:30   4 °C	10:00 2°C 10:15  -1 10:45   -1°C 11:15  -4°C	2in	2.78in
20°C	0°C	0tsp	8:30 20°C 9:00 6°C 9:15 0°C 9:30 N/A	10:00  N/A 10:15  N/A 10:45  N/A 11:00  N/A	2in	2.3in

1.) How much does water expand when frozen?

From my own experiment the water expanded from about 0.3 inches to about 0.78 inches when frozen.

2.) When is water the smallest? at what temperature.

From doing my experiment water was the smallest when it was at room temperature.

3.) What happens when salt is added to the water?

When salt gets added to water, it causes the water to break down the salt molecules, which slows down the process in which water freezes.

4.) Does the amount of salt added effect the freezing point?

I believe that the amount of salt added to water effects the water’s freezing point. I believe this because when I added more salt to my water it took longer for the water to freeze compared to my cup that did not have salt mixed with the water. The more salt I added, the longer it seemed to take for the water to completely freeze.