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Unsuccessful lab project :(

  1. Apr 6, 2015 #1
    Hello,

    Last week our group did a project to see out of carbs, protein, and lipid which one produces the more carbon dioxide, and we were unsuccessful.
    Here is what we did:
    • 4 test tubes
    • 1 tube was control (4ml yeast and 10ml water)
    • second tube (4ml yeast; 5ml water; 5ml lipid)
    • third tube (4ml yeast; 5ml water; 5ml protein)
    • fourth tube (4ml yeast; 5ml water; 5ml carbs)
    We put the balloons on the top of each test tube to see which one will expand more. Unfortunately, after 10 hours none of them produced the CO2.

    What could be the possible reason? We will have this project tomorrow again, so how should we design our project now?

    Thank you!
     
    Last edited: Apr 6, 2015
  2. jcsd
  3. Apr 6, 2015 #2

    Evo

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    Staff: Mentor

    Was the water warm enough or too warm? Was the yeast old?
     
  4. Apr 6, 2015 #3
    Water wasn't warm; we used the tap water at normal temp. I don' know about the yeast because we just mixed that with the water, and then put that in the test tube.

    For other groups in the class it worked little bit, but didn't work at all for us.

    What others did: they mixed yeast, protein, lipid, and water (first one); yeast, protein, carbs, and water (second one); and yeast, lipid, carbs, and water (third one).
     
  5. Apr 6, 2015 #4

    Evo

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    Staff: Mentor

    What temperature was recommended for the yeast? Most yeast requires warm water. Did the yeast have an expiration date? If the yeast is old, it may not ferment.
     
  6. Apr 6, 2015 #5
    I don't know about the temperature, but it worked for all other groups. Not successfully, but at least they showed some of their work.
    How should I design combination for the next time?
     
  7. Apr 6, 2015 #6

    Evo

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  8. Apr 6, 2015 #7
    Thank you so much!
     
  9. Apr 6, 2015 #8

    Evo

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    Staff: Mentor

    Good luck!
     
  10. Apr 9, 2015 #9

    BobG

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    This is interesting. It would be fun to analyze the results by the activities of the groups.

    Did the experiment work better for the first groups to get their water? (Most interior water pipes aren't insulated and the water is near room temperature. Eventually, the warmer water is used up and cooler water from the underground water pipes starts flowing.)

    Did the groups with working experiments spend more time handling the test tubes than other groups? (Their body temperature would warm the water in the test tubes.)

    Both variables would affect how well their experiment worked. Some may have handled their test tubes a lot, but started with a lower water temperature, etc.
     
  11. Apr 14, 2015 #10
    In making bread, I have learned the hard way (literally), yeast is very sensitive to temperature. Some packets come dead too, I think.
     
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