Mini-experiment 1:
Investigation of heat, specifically with water and salt
Background:
I remember my mother always telling
me that salt makes water boil quicker, but I always wondered why that was. In class we have briefly investigated the
specific heat of water and how the addition of salt changes the specific
heat. When salt is spread over snow and
ice, it melts faster or it lowers the specific heat. Although I am pretty certain that the water
will boil quicker when salt is present, I want to investigate the variance. This
will be tested by comparing the boiling time of each separate scenario.
Hypothesis: There will be a decrease in boiling time between
water with salt added and without salt added.
Null hypothesis: there will not be a significant difference in
boiling time between water with salt added and without salt added.
Independent variable: whether the water has salt added or
not.
Dependent variable: time to boil.
I will standardize:
· -the salt added (1 Tbs)
· -the amount of water (6 cups)
· -the heat (high)
· -pot (same)
· -the initial temperature of the water (13° C)
Results
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Trial 1
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Trial 2
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Trial 2
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Time to boil w/salt
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789
|
808
|
795
|
|
Time to boil w/out salt
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810
|
814
|
809
|
|
|
With salt
|
Without salt
|
|
Average
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797.3 seconds
|
811 seconds
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|
Standard Deviation
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9.712535
|
2.645751
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|
SEM
|
5.607535 |
1.527525
|
With a p-value of .08, the data supports the null hypothesis
that salt does not have a cause a significant decrease in time to boil. The limitations from this experiment would
arise from possible human error in terms of measuring when the pot was “boiling”. It is tough to stop the time as soon as the
water seems to be boiling. Also, I did
not stir the salt into the water so it did not dissolve in the solvent before I
heated the pot.
Discussion
The null hypothesis was supported
that the salt would not cause a significant decrease in the boiling time of water. Although salt is accepted to lower the
specific heat of water and has been shown through salting streets and prior
research, in this particular setting it did not show a significant change. This experiment would be more accurately observed
and analyzed if there were two identical pots being heated simultaneously. This way, the level of boiling would be able
to be recognized more accurately. It was
hard to tell the level of boiling for each trial, but if there were multiple
being heated simultaneously it would be easier to compare between them as they
heat. This experiment would be
interesting to run with different salt concentrations at different water
volumes; that way an optimal salt to water ratio could be examined.
Pictures
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| Ready to boil! |
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| Water with salt |
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| Materials |
Hey Pat! I loved this experiment. We both had the same question when our mothers added salt to the water. I found your data to be interesting. I actually assumed that the water would definitely boil faster but I guess I should now read up on the subject. I definitely think you should try this using two of the same pans at the same time. This may help you clarify which one went faster. I also wonder if sometime you could test out the materials of pans and see if that has an affect. Great job on your project!
ReplyDeletePat,
ReplyDeleteWhat a cool idea! When I was thinking of an idea to do all that kept popping into my head was to do an experiment on food. You took a whole new approach very out of the box in my opinion and simple. Your results were extremely accurate as well and the graphs were easy to read. In comparison with other experiments I have looked at, yours seems to be the closest in regard to the results you obtained. But despite the closeness your hypothesis proved to be supported so high five for that one there.
Overall, my interest was kept through out the experiment and I learned a few things to improve upon for my own experiments.
Way to Go !
Sarah.
Hi Pat,
ReplyDeleteIt is always good to do an experiment with information we learned about in class. Your explanation of the specific heat and the way salt and water react together were both thing we discussed in class. Interesting conclusion to your experiment, the salt water did end up boiling faster but not enough to be a significant difference. It would be interesting to see if different brands of salts made the water boil even faster.
-TC