The large variability in the yeast experiments, in both experimental and control groups, is disappointing.
However, my data still fits with Motta's results. Indeed, in his experiments, the 110mT group only had a small CO2 overpressure with respect to control. There was a 30% overpressure only in the 220mT group and only after many hours. Also, a biologist friend of mine pointed out that, in the Motta experiments, the pH was regularly adjusted by hand in both groups. Indeed, increase of CO2 partial pressure would lead to acidification of the growth medium. However I cannot do that since I cannot open the flasks without losing the pressure value.
Another point of concern that has been pointed to me is that the yeast are very sensitive to temperature, and I did not take any measures against air currents.
To avoid all these problems, I will take the following measures in the next experiment.
- The flasks will be enclosed in a plastic box to eliminate current drafts.
- The plastic box will be covered in aluminum foil to protect the flasks from light.
- Each flask will be connected to an empty 330mL Perrier bottle. This will increase the volume to about 400mL, which should:
- Absorb small variations due to the
- Decrease total pressure, leading to less effect on medium pH, and reducing the incidence of leaks
- The flasks will be washed with chlorine bleach before the experiment.
- I will use boiled water.
- I will use 0.9% glucose.
- I will use two square magnets to double the field.
