Acid Rain and soil PH

[Skrunski]

im doing an expirement about how the change in soil pH due to acid rain will affect plants. i planned to grow 3 indivual pots of wheatgrass in the span of 2 weeks and water each one with a different spray bottle. One was filled distilled water to have a neutral pH so it can stimulate normal gorwth. The two others i used the same distilled water but added a small amount of vinegar so i could get a pH of 3 and 4. however when i measured the regular distilled i got a pH of 5 not 7. my overall question is can i still use the distilled water for the normal growth even if it has a pH of 5?.

[aredlife1]

Hi, that sounds like a really good experiment!
Think about why you are using the distilled water group. Usually, it is used as a “control,” which means it shows how the plants grow under normal conditions. Even if your distilled water has a pH of 5 instead of being perfectly neutral, you can still use it as your control because it is less acidic than the vinegar water.
You can also mention in your “Limitations” section that the distilled water was not completely neutral.

This article explains why the pH of distilled water can change:
https://sensorex.com/understanding-the- ... ter_Change

[MadelineB]

In addition to the excellent suggestions by the above expert, I suggest that, if possible, that you test at least 3 wheatgrass plants in each of your "treatment" groups. This will give you 3 measurements of the effect of each treatment on wheatgrass and you could see whether the measurements within one group are more varied than the other 2 groups. Judges really like to see plots showing several observations per group!

Best of luck with your project!

Madeline