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Sunday, March 27, 2011

The purpose of this investigation is to find which materials slow down the cooling process. For the investigation on heat transfer, I chose to test aluminum foil, plastic wrap, wax paper, and a paper towel. I poured 150 mL of boiling (100 degrees Celsius) water into 8 oz styrofoam cups. I covered each cup with the a 13 cm by 13 cm square of each of the materials and secured them with a rubber band. I then let the cups sit on a counter for 30 minutes. After 30 minutes I checked the temperature of water in each of the cups. The results are in the table below: Material 13 by 13 cm squre Aluminum Foil Wax Paper Paper Towel Plastic Wrap Temperature In °C, after 30 minutes. 48°C 44°C 42°C 46°C This investigation covered heat transfer through two methods, first it was through evaporation and radiation. The aluminum foil is the least porous of the materials, therefore it had the least evaporation of the water and cooled at a slower rate. Aluminum foil also has a reflective surface and reflects the heat energy back to the water in the cup, rather than letting the heat escape. If I were to repeat the investigation with different materials, I would probably use different thicknesses of cloth. The cloth with the biggest thickness would probably keep the most heat because it is the one that would allow the least evaporation. This investigation could be done with other items that are not water. I would love to retry this investigation with a non-liquid like uncooked beans, or lentils. I would heat the beans and place them in cups and cover them with various materials. Since beans do not contain much liquid that would evaporate and speed up the cooling process, the temperatures might vary. * What, specifically, would you like students to learn from this experiment? Did you achieve this goal when you engaged in the experiment?

The purpose of this investigation is to find which materials slow down the cooling process.


For the  investigation on heat transfer, I chose to test aluminum foil, plastic wrap, wax paper, and a paper towel.  I poured 150 mL of  boiling (100 degrees Celsius) water into 8 oz styrofoam cups.  I covered each cup with the a 13 cm by 13 cm square of each of the materials and secured them with a rubber band.  I then let the cups sit on a counter for 30 minutes.  After 30 minutes I checked the temperature of water in each of the cups.  The results are in the table below:


Material
13 by 13 cm squre
Aluminum Foil
Wax Paper
Paper Towel
Plastic Wrap
Temperature
In °C, after 30 minutes.
48°C
44°C
42°C
46°C

This investigation covered heat transfer through two methods, first it was through evaporation and radiation.  The aluminum foil is the least porous of the materials, therefore it had the least evaporation of the water and cooled at a slower rate.  Aluminum foil also has a reflective surface and reflects the heat energy back to the water in the cup, rather than letting the heat escape.

If I were to repeat the investigation with different materials, I would probably use different thicknesses of cloth.  The cloth with the biggest thickness would probably keep the most heat because it is the one that would allow the least evaporation.

This investigation could be done with other items that are not water.  I would love to retry this investigation with a non-liquid like uncooked beans, or lentils.  I would heat the beans and place them in cups and cover them with various materials.  Since beans do not contain much liquid that would evaporate and speed up the cooling process, the temperatures might vary.

  • What, specifically, would you like students to learn from this experiment? Did you achieve this goal when you engaged in the experiment?

4 comments:

  1. Hi Ana,
    I noticed that your temperature changes were different than those experiments that used coffee mugs and that you used Styrofoam cups instead. Do you think you would have gotten similar results had you used ceramic mugs? I did appreciate your explanation of why foil is a good insulator, I hadn't anticipated that when I did my own experiment.

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  2. Ana,
    I too had discoved that aluminum foil was the best insulator. My prediction was such and was correct. I thought of it in the same way you did. I thought if it is used a lot in baking and cooking, it must have some ability to hold in heat. Mine was even colored on the bottom side from the heat. It almost looked scorched.

    You idea about using the beans and lentils is a good idea too. If you think about it there are some of those heating pad bag type things that you can microwave. They have objects in them similar to beans and retain heat for quite awhile.

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  3. Ana,
    It begs to mind the activity where students create solar ovens! Unfortunately in Oregon, with only have 60 cloud free days a year (those being in summer), making one to use with students during the school year is next to impossible unless you have big heat lamps but then what would be the purpose? I tried styrofoam peanuts in a plastic bag, didn't work that well. I suppose I didn't have enough peanuts to really do a good job. My success was several layers of cardboard shaped in a cap around the cup. (like the Starbucks sleeves).

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  4. Solar ovens are a great idea! We have a high percentage of sunny days in West Texas, and temperatures go up to the 100's. Definitely will be trying solar ovens with the kids!

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