Insulation project didn't turn out as we hoped

AFTER you've done your research and concluded your experiments, it is time to prepare for the science fair. Ask specific questions about preparing for a science fair, including how to set up your display board, how to prepare a presentation, etc. (Please post questions about selecting a project or conducting your experiment by posting in the appropriate "area of science" forum.)

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Insulation project didn't turn out as we hoped

Postby mamanachan45 » Mon Nov 18, 2013 2:01 pm

Hi, my 5th grade son is working on his science project with insulation.
His Question is: Which type of insulation (cotton, wool, or fat) slows down the heat loss compared to no insulation? We divided a shoe box in 4 equal parts, and placed a canning jar into each space. We filled gaps in each sapce with those insulation materials with one gap left unfilled (no insulation) . We poured tap water into the jars and place lids on them, and stored the whole box in a freezer. recorded water temperature every 20 mins for 100 minutes.

The result is:
the temperature in a jar with no insulation went down steadily and reached 32F after 80min. Other three went down slowly and reached 50F after 80 min, but the way the temperature went down in those three jars were almost same, no much difference at all. When my son made a line graph to show how the temperture went down , those three line are almost one thick line. We were expecting to see wool keeping heat better that cotton, and possibly lard ( as fat) is the best material to keep you warm. But, They were all same. We are very disppointed to see no difference.

We are wondering if our procedure was not good. Could you tell us please what went wrong in our project? We would really appreciate that. We would like to conclude this project suggesting what we could have done to see more reasonable results.

Thank you very much!
mamanachan45
 
Posts: 1
Joined: Mon Nov 18, 2013 1:08 pm
Occupation: parent
Project Question: How much insulation materials (cotton, wool, or fat) slows down the heat loss compared to no insulation?
Project Due Date: NOv 26, 2013
Project Status: I am finished with my experiment and analyzing the data

Re: Insulation project didn't turn out as we hoped

Postby theborg » Fri Nov 22, 2013 2:40 pm

mamanachan45,

Welcome to the forum and thank you for your question.

Results in science are not always as expected, which is the point. It may be that the materials you chose have very similar insulating properties. However, one must really monitor the control variables.

I'm assuming, but verify:
1) The size and shape of the jars were the same. The glass of the jar itself provides some insulation to the water inside, you have to ensure it is the same for all test subjects.
2) Ensure the amount (weight) of water in each jar is exactly the same.
3) Ensure the starting temp of water in each jar is exactly the same (say from 100 deg C).
It sounds like you probably did all of that...now also:
4) Ensure the "thickness" of the insulation material around each jar is the same on all side (including the bottom and top) for all samples. For example ensure 1 cm thickness of wool around jar 1, 1 cm of cotton around jar 2, and 1 cm of lard around jar 3, and of course control left without insulation.

I could see that the heat loss from each insulated case was probably slightly different from each other, and obviously quite different from the uninsulated control, but the result may be masked by the heat loss out the top and bottom, which from your description, sounds like they were left uninsulated. Also, between insulated jar sections, you have double insulation of different materials.

I would re-run the experiment by completely encasing each jar in insulating material and placing them separately in the freezer vs in the same box where the surface area exposed to the cold could be just different enough to skew results. I would even run the test on each case individually so that each test subject could be placed in the exact same spot in the freezer, eliminating the possibility of one test subject to be in a slightly "cooler" or "warmer" part of the freezeer. Also, i'd repeat at least 3 times to verify results and get an "average" insulating index factor for each test material.
I hope this helps.

theborg
----------
"As the circle of light increases, so does the circumference of darkness around it."
~ Albert Einstein
theborg
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Posts: 224
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Occupation: US Air Force Space & Missile Operations
Project Question: "To explain all nature is too difficult a task for any one man. 'Tis much better to do a little with certainty and leave the rest for others that come after you, than to explain all things by conjecture without making sure of anything." - Sir Isaac Newton
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Project Status: Not applicable


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