Does hot water or cold water freeze faster?
Hypothesis: Cold water will freeze faster because it is already at a colder temperature to begin with.
Experiment Performed:
-The objective of this experiment was to find out which will freeze faster, hot water or cold water
-My hypothesis: The cold water will freeze faster because since it is already cold, it will take less time to freeze
-A 16oz. plastic container is filled with a half cup of hot water
-A 16 oz. plastic container is filled with a half cup of cold water
-I made sure to use the same size container, and also made sure that the same material was being used
-Each container is placed in the freezer at the exact same time
-The hot water is placed on the right side, the cold water on the left
-The stop-watch on my cell phone is used to keep track of time, the water is left in the freezer for three minutes, then checked, and continuously checked once a minute until the first glass of water is frozen
-The results: the cold water did indeed freeze faster
-I ran the exact same experiment several times, and the same results occurred.
-Conclusion: The cold water freezes faster because it started out closer to a freezing temperature and will take less time to actually solidify
Does hot water or cold water boil faster?
Hypothesis: Cold water will boil faster because there is more of a chemical reaction to with the heat.
Experiment Performed:
-The objective was to find out whether hot or cold water would boil faster
-My hypothesis: Cold water will boil faster because there is more of a chemical reaction with the heat
- I used 2 cups of water and place them in a metal pot on high temperature. I then used my stopwatch in order to see how long it took to boil the water
-The pot was then placed under cool water in order to lose all of its heat
-the same experiment was then performed with cold water
-On the first trial my hypothesis was rejected because the warm water took approximately 40 seconds less to boil
-New Hypothesis: The warm water will boil faster because it is already closer to a boiling temperature
-Experiment was repeated and the same results were obtained
-Conclusion: Hot water will boil faster than cold water in most cases.
Does salt water freeze faster or slower than regular water?
Hypothesis: Salt water freezes faster than regular water because it has more of a chemical reaction with the cold temperature.
Experiment performed:
-The objective was to find out if regular water or salt water will freeze faster
-Hypothesis: Salt water will freeze faster
-I used a half cup of water as I did in my previous experiment
-The only difference was using 32 oz. containers instead of 16
-each container was filled with a half cup of the same temperature of water
-the container on the right hand side labeled salt was then doused with salt
-results: the salt water froze faster
-experiment was repeated and results were the same
-conclusion: salt water freezes faster than regular water
3. Data in the form of a graph or table
4. Show data of experiment repeated
Cold H2O V. Hot H2O Freeze | Experiment 1: Cold H2O was able to freeze faster than the Hot H2O | Experiment 2: Cold H2O was able to freeze faster than the Hot H2O | Conclusion: Cold H2O will freeze faster than Hot H2O in most circumstances |
Cold H2O V. Hot H2O Boil | Experiment 1: Hot H2o was able to boil faster | Experiment 2: Hot H2O was able to boil faster | Conclusion: The Hot H2O will boil faster than the Cold H2O in most cases |
Salt H2O V. Regular H2O Freeze | Experiment 1: Salt H2O froze faster | Experiment 2: Salt H2O froze faster | Conclusion: Salt water will freeze faster than regular water in most cases |
5. List your controlled variables for your experiment
My controlled variables for all experiments:
-1/2 cup of water for freezing, 2 cups of water for boiling (amount of water)
-plastic containers used
-metal pot used
-temperature of freezer
-temperature of stove
6. Formulate a theory that answers the questions posed.
Question 1: The results that I obtained to the first question posed, “does hot or cold water freeze faster?” told me that the cold water would freeze faster, but there is scientific proof and explanation to hot water freezing faster than cold. A lot of the internet sites that I visited provided statements that claimed hot water did indeed freeze faster than cold. Here is one of those statements.
“The phenomenon that hot water may freeze faster than cold is often called the Mpemba effect. Because, no doubt, most readers are extremely skeptical at this point, we should begin by stating precisely what we mean by the Mpemba effect. We start with two containers of water, which are identical in shape, and which hold identical amounts of water. The only difference between the two is that the water in one is at a higher (uniform) temperature than the water in the other. Now we cool both containers, using the exact same cooling process for each container. Under some conditions the initially warmer water will freeze first. If this occurs, we have seen the Mpemba effect. Of course, the initially warmer water will not freeze before the initially cooler water for all initial conditions. If the hot water starts at 99.9°C, and the cold water at 0.01°C, then clearly under those circumstances, the initially cooler water will freeze first. However, under some conditions the initially warmer water will freeze first: if that happens, you have seen the Mpemba effect. But you will not see the Mpemba effect for just any initial temperatures, container shapes, or cooling conditions.”
Written Nov, 1998 by Monwhea Jeng (Momo),Department of Physics, University of California
http://www.desy.de/user/projects/Physics/General/hot_water.html#Yes
My final theory on Hot V. Cold water freezing: Cold water will freeze faster when there is a definite difference between the cold and hot temperatures. When the Hot or Cold water is comparable in temperature then the hot water may take over, and thus the mpemba effect occurs.
Question 2: The hot water was able to boil faster than the cold water and my original hypothesis was proven wrong
Question 3: The salt water froze faster, and this was my original hypothesis.
9. Describe the scientific method/process and how each step correlates to your own experiments.
The question was: Which will freeze faster, hot or cold water?
Background research: A lot of the websites I visited claimed that the hot water would freeze faster than the cold water because it reacted with the freezing temperatures in a much more significant way. A lot of websites also stated that it depended highly on the temperature of the water. If it was drastically cold or drastically warm. Obviously if the water is so hot that it is almost boiling, or the water is so cold that it will freeze in two seconds, then the results will conclude that the cold water freezes faster. The majority of the sites also said that it depended on the temperature of the water in most cases.
Hypothesis:
Hypothesis 1: My original hypothesis was that the cold water would freeze faster because it was already cold, and my experiments held true to that.
Hypothesis 2: Cold water will boil faster
Hypothesis 3: Salt water will freeze faster
Experiment: I ran an experiment that I thought worked quite well with the materials I had. It was then performed several times and the same results were obtained.
Analyze the data: I was proven right with my original hypothesis and it was clear that cold water will freeze faster in the environment I was in. The second hypothesis proved to be wrong, but the experiments were consistent in doing so. The third experiment went as planned.
Communicating results: I stated that the cold water will freeze faster because it takes less time to reach freezing temperatures. This was the way I went about communicating my results and findings. I also stated that the warm water boiled faster and that I was proven wrong, and that the salt water froze faster and this was a correct theory.
8. Video or animation that shows how water molecules are arranged in the three states of matter for water.
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