View the Science Fair Projects about Heat Retention

Abstract: The Feat of Heat
Student: Nikhil
13 years old
Michigan, U.S.

My experiment is about heat retention. The experiment compares the heat retention of salt water against tap water.

My experiment uses two thermometers and special equipment that is used for amateur lab studies. The goal of the experiment is to see if salt has an affect on the heat retention of water.

Question: Does fresh water have a slower or faster heat retention than salt water?

Hypothesis: If salt is added to water then it will it will cool faster then fresh water.

Purpose: The purpose of my experiment is to compare salt water to fresh water and see which one will cool the slowest. I am doing this because keeping heat in foods and materials is very important. If there is a basic material that can increase the heat retention of an object then it can help us in times of need. The variable that I was testing for was the amount of Salt in the water. My constants were: The same container to hold the water. The same starting temperature for both the water samples. The same two thermometers used throughout the experiment.

Procedure

1. Collect all of the Materials listed.
   
2. Fill both containers with two cups of fresh water.
   
3. Let the containers of water sit for about 10 minutes.
   
4. Add four tablespoons of salt to one of the containers and mark label it - salt water.
   
5. Get out a CBL and compatible calculator.
   
6. Connect the two temperature probes to the CBL and link the calculator to the CBL.
   
7. Turn on the Calculator and load Datamate software, prepare a run for data collection every minute for 80 minutes.
   
8. Put the temperature probes in the water and look on Datamate to see the Temperature of both probes.
   
9. Start the stove when the temperature of the Water is at room temp.
   
10. When the Temperature of the water reaches approximately 90 degrees Celsius start the Data collection of the CBL.
    
11. When the water starts to boil turn off the stove.
    
12. The CBL and Calculator should be taking readings every minute so wait until the water reaches room temperature and stop the Data collection. (Take a look at the calculator to make sure it is recording the temperatures properly.)
    
13. When the water reaches room temperature, stop the data collection and save the Data.
    
14. Using a computer to upload the results.
    
15. Do this as many times until satisfied with the results.

Materials used: Two identical containers, Two Vernier CBL combatable thermometers (I used stainless steel thermometers), CBL, TI-Calculator compatible with CBL and Datamate software, Clock, Two cups of Water, Two tablespoons of salt, and a Stove.

Conclusion: My hypothesis was right. The salt had an effect on the heat retention of water. As it made the water cool faster after completing two runs, the results were surprising as no obvious differences could be observed. But when the third trail was made the scientific theory came to sense.

Even with this happening I can still find a trend line in that adding salt to water has very little to no effect on the heat retention of water.

On my third trail I added more salt to see if adding more salt made a difference. The salt water-cooled in much less time then the tap water. On my fourth trial the salt water-cooled faster.

However, I wanted to see more dramatic results so on my 5th, 6th, and 7th trial. At this point, I added the amount of salt needed to completely saturate the water. This only raised the boiling point of the water.

Now I thought I could see a difference by analyzing the data. When I looked at the graphs that had been made I could not tell what had happened so I went into the raw data and found the difference between the temperatures of the salt water and the fresh water.

I came to a conclusion after running the tests 7 times. The graphs and the analysis showed that by adding salt the time taken for salt water to reach room temperature decreased.

My Scientific Research included specific heat and lateral heat. In my experiment I changed the specific heat of water by adding salt. Specific heat is the joule per kilogram kelvin, J•kg-1•K-1 or J/(kg•K), which is the amount of energy required to raise the temperature of one kilogram of the substance by one kelvin. Heat capacity can be measured by using calorimetry. (Refer to research for more info). When I added Salt I changed the specific heat from 1 (fresh water) to .94(salt water).

When researching I came up with an article about salt changing the boiling point of water. I added 3 tablespoons of salt in my third trial to see if adding more salt were to make a difference in the heat retention. It made the boiling point of the water 101 degrees.

Another scientific term I came across was an endothermic reaction. This type of reaction deals with the loss of heat. This loss of heat by adding salt could have caused an endothermic reaction. If it did we could help keep foods and materials warmer by adding salt to them. But with more research I have found that salt does not cause this special reaction.

My Future questions were: What other chemicals help water retain its heat for longer? Does the Dead Sea have a different temperature or different properties because of its level of Salt? What properties of water can we change to make its heat retention longer? Does the density of the substance have anything to do with its heat retention?

Bibliography & References

1. “Specific Heat”, Winkipedia, 18:43, March 3 2006, http://en.wikipedia.org/wiki/Specific_heat

2. “Ask The Scientist” Newton, March 1 2006, http://www.netwton.gep.anl.gov

3. “Specific Heat”, Hyperphysics, February 22 2006, http://hyperphysics.phy-astr.gsu.edu

4. Viegas, Jennifer- The Laws of Thermodynamics – An anthology of Current Thought, Rosen Pub Group - 08/01/2005

5. “Experiment to investigate cooling water”, Coursework. Info, February 23 2006 http://www.coursework.info

6. “Evaporating water” Oracle Education, Feb 28 2006,
   Click Here to View
   -evaporating water

7. “Heat Retention” Oracle Education, March 2 2006,
   Click Here to View