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Homework Help: Help me find experimental errors in my bottle rocket experiment, Hurry please?

  1. Sep 28, 2009 #1
    Could you please help me find experimental error in bottle rocket experiment that could have affected my results. The experiment is where a bottle gets filled with water, a third of their volume and then they get pressurized to fly in the air.

    So could you please find me experimental errors for this experiment?
    Hurry please I need them as soon as possible!!!

    Thanx in advance!!
    Last edited: Sep 28, 2009
  2. jcsd
  3. Sep 28, 2009 #2
    What do you mean by experimental errors? Do you mean factors that could affect the flight that you haven't considered, or do you mean uncertainties in your measured and derived quantities?
  4. Sep 28, 2009 #3
    What were you actually measuring.I am guessing the volume of water used,the number of pumping actions and the height reached.How did you display your results..did you plot a graph?
  5. Sep 28, 2009 #4
    I mean factors that have affected my results!
  6. Sep 28, 2009 #5
    What results? what measurements did you take?
  7. Sep 28, 2009 #6
    I obtained the result when I measured the angle between the launching starting point and the apex of the trajectory of the bottle rocket. I was 30 metres away of the starting point whenmy friend started pumping to measure this angle.
  8. Sep 28, 2009 #7
    I don't think you can get anything meaningful out of those measurements. You estimated the height of the apex as well as its horizontal distance from the origin, so those are out.

    And you neglected the important things (Mass of water, pressure of air inside) not to mention those that are out of the scope of your analysis (Air resistance, turbulence, I suppose the rocket propulsion is fairly complicated as well, especially since it deals with pressure as well)
  9. Sep 28, 2009 #8
    If I understand this correctly your friend measured the angle.Knowing the method used you should be able to make a reasoned estimate of the uncertainty in his/her measurement e.g for one measurement the angle was 30 degrees plus or minus 5 degrees( or whatever it happened to be).It is best to express errrors as a percentage rounded down to the appropriate number of significant figures.
    You measured the apex in other words the height reached?Wow how did you do that?I guess that whatever your method the experimental error was huge but you can at least do a reasoned but rough estimate.
    It is so difficult to give advice here without the details of the measuring techniques you used but good luck with it,it sounds like a fun experiment.
  10. Sep 28, 2009 #9
    I agree but he probably has to make some sort of estimates no matter how crude.
  11. Sep 28, 2009 #10
    Yes, I did get the feeling I was a bit too harsh with my criticism, I apologize.

    As far as possible estimates go, the question is what he was trying to measure...
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