Homework 1-18-11

1.How much does water expand? I found this very difficult to measure due to my cup and i wasn't sure how it was actually meant by measuring if wate ractually expanded, but when i started i did measure the length of the top of the cup to see how long it was and the length was

approximatley 3 inches long. It was also the same on the top at the end of the expirment.

After looking online for awhile i was able to find that water will expand and this because when its freezing it is better off to make hydrogen bonds while turning to ice.
2. When is water the smallest? What is the temperature?Truthfully, i have no idea when water is the smallest, but if stated above if water expands around freezing temperatures i would best guess that water is the smallest when it is around room temperture. Room temperature would allow it to be activie and still make shapes but no raise the tempeature or the height of the water.


3. What happens when salt is added to water?    
     When you put salt on frozen water an endothermic reaction takes place. this then decreases the temperature of the water.
4. Does the amount of salt added affect the freezing point of water?
     Yes, because it dops the freezing point forcing the temperature to drop in order for the water to re freeze allowing the salt to stop working.

Experiment

Time	Temperature in Cup	Temperature Outside	How thick is the ice in cm?
5:00 pm	18 degrees C or 64 degrees  F	16 degrees F	n/a
5:30 pm	5 degrees C or 41 degrees  F	14 degrees F	n/a
6:00 pm	1 degrees C or 34 degrees  F	14 degrees F	0.1 cm
6:30 pm	1 degrees C or 34 degrees  F	14 degrees F	0.2 cm
7:00 pm	1 degrees  C or 34 degrees  F	14 degrees F	0.3 cm
8:00 pm	1 degrees  C or 34 degrees  F	14 degrees F	0.6 cm
9:00 pm	.5 degrees C or 33 degrees F	14 degrees F	1.0 cm
10:00 pm	.5 degrees C or 33 degrees F	14 degrees F	1.3 cm

2 cups of water were placed in a plastic up. Before the water was put outside at 18 degrees C or 64 degrees F I added 1 tsp of salt into the cup and the water dissolved the salt allowing it to disappear. After seeing what it did at 18 degrees C or 64 degrees F I then washed the cup out and put new water in it and got that water to the same temperature as before and put that water outside. On the graph above, it shows the water at different times and temperatures through the night.

At 10:00 pm I took the ice in from outside and decided to sprinkle the 2 tsps of salt on top of the ice to see what will happen. After putting the first tsp on the ice and getting the second tsp ready, the ice began to crack and make cracking sounds.  This graph shows what I saw every 15 minutes for 1 hour after putting the salt on the ice.

Time	Description of what I saw and heard
10:00 pm	Cracking of the ice began after putting 2 tsp. of salt on the ice.
10:15 pm	Looks like there are little bubbles in the ice, but there just actually grooves in the ice. I also added an additional tsp. of salt.
10:30 pm	When looking at the cup again full of ice, I saw that there was little water on top with a lot of ridges.
10:45 pm	After another 15 minutes, there was more water sitting on top of the ice and you could still see the little bumps or ridges on the ice. I did add another 1tsp. of salt to see what that would bring.
11:00 pm	After observing for the last time of ice,  there was more water on top of the ice and the bumps/ridges were still there but slowing going away as it begins to melt.

At 11:00 pm i brought the cup inside to allow it to melt and when i woke up in the morning at 8:00 am the temperture inside the cup was 20 degrees C or 68 degrees F. The cup changed to room temperture because the heat inside my apartment is at 68 degrees F.