Maggot respirometers

A respirometer is a device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and/or carbon dioxide. They allow investigation into how factors such as age, chemicals or the effect of light affect the rate of respiration. In this experiment, I will be testing the respiration of maggots and its correlation with different temperatures. Therefore, temperature is the dependent variable and light, noise, time and number of maggots are the independent variable.


  • Maggots in order to have a representative living organism
  • Respirometer to measure the respiration
  • Hydrogen carbonate indicator in order to measure the Ph value
  • Pipette in order to measure the carbonate indicator more exactly


  1. I poured in 2,5ml of the hydrogen carbonate indicator in two different respirometers.
  2. I added 10 maggots in each respirometer.
  3. One cup was left at room temperature (20°) and the other was put in a water heater that possessed the temperature of 30°.
  4. The different cups were left in their environment for an unmeasured amount of time and the color of the indicator was observed.


 When heat increases the enzyme Collison would increase as well and therefore the carbon dioxide amount would rise.


  • The indicator in the respirometer in room temperature had turned orange and therefore possessed the Ph rate of 8.
  • The indicator in the respirometer in the heater had turned red and had the Ph rate of 8,6.

The results did not relate to the initial hypothesis. This indicates that there were multiple errors that hindered the desired outcome. For example, whilst the number of maggots was the same some of them were dead and hence did not practice respiration.

The lack of timing led to further inaccuracies. The respirometer in room temperature stayed longer than the one in the heater as we drowned our first experiment and had to redo it.

Another critical point is that the room we did the experiment in was too cold and therefore did not have the exact room temperature of 20°. This could have tempered with the final results as the temperature difference was greater than anticipated.


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