Activity 1: Scientific Method and States of Matter

Does salt water freeze faster or slower than regular water?




Experiment 1- Salt Water, Regular Water and Ice Cube Tray




Experiment 2- Salt Water, Regular Water and Plastic Cups

2.  My hypothesis to whether salt water will freeze faster or slower than regular water is that the regular water will freeze first because there is nothing added to it.  I would guess that because of the salt being added to the other container of water it is changing the state that it is in and will cause it to freeze at a different temperature.

3.

Experiment 1: Ice Cube Trays
Time	Regular Water	Time	Salt Water
11:14	Liquid	11:14	Liquid
11:30	Liquid	11:30	Liquid
11:45	Ice crystals are starting to form on the side of ice cube tray	11:45	Liquid
12:00	Thin layer on top	12:00	Small crystals for on edge on top of ice cube tray
12:15	Beginning to freeze, getting hard on top	12:15	More water crystals on top
12:30	Mostly froze, a few water bubbles in the bottom	12:30	Thin layer on top forming
12:45	Froze	12:45	Top is hard, water on bottom

Experiment 2: Plastic Cups
Time	Regular Water	Time	Salt Water
3:05	Liquid	3:05	Liquid
3:20	Liquid	3:20	Liquid
3:40	A few water crystals are starting to appear around edge of glass	3:40	Liquid
3:55	Thin layer of ice on top of glass	3:55	Water crystals are forming- not many
4:15	Bottom of glass of water is still liquid, but top is getting hard	4:15	Thin layer on top
4:45	Froze	4:45	Top part is getting hard

5. Controlled Variables: Water, ice cube trays, plastic cups, Great Value Brand Salt.

6. I believe that the regular water came to the freezing state first because regular water freezes at 0' F whereas if you add salt to wter, it's reezing point becomes lower. 

7.  Image of atoms that make up water molecules:

8. Animation that shows how water molecules are arranged in the three states of matter for water. (Once link is open click on the word Magnify under the picture.)

Solid State: http://www.visionlearning.com//app/obj_tools/library/objects/Flash/VLObject-1435-030317040352.swf

Liquid State:

http://www.visionlearning.com/library/flash_viewer.php?oid=1434&mid=120

Gas State:

http://www.visionlearning.com/library/flash_viewer.php?oid=321&mid=120

9. Scientific Method: 

• Ask a Question
• Do Background Research
• Construct a Hypothesis
• Test Your Hypothesis by Doing an Experiment
• Analyze Your Data and Draw a Conclusion
• Communicate Your Results

Step 1: Ask a question: Does salt water freeze faster or slower than regular water?
Step 2: Do background research: Has there been other research done?  Researched the topic online.  Also looked at options as to how I wanted to setup this experiment.  Will the kind of salt used make a different?  How much salt should I put in?

Step 3: Construct Hypothesis: I thought that the regular water would freeze first because there has been nothing added to it.
Step 4: Test with an experiment: As my pictures and graph show above, I tested this experiment twice.  I used the same amount of water both times but used ice cube trays and plastic cups.
Step 5: Analyze results/Draw Conclusion: When looking at my results it showed that the regular water froze before the salt water both times that I tested it.
Step 6: Hypothesis is True or Hypothesis is False or partically true:  My hypothesis was true as my data shows the results of a quicker freeze time for regular water.
Step 7: Retest the experiment: This time I used plastic cups instead of the ice cube trays. 

Step 8: Report Results: After performing this experiment for a second time I found that regular water freezes faster than salt water.