Are there more lightnings with acid clouds?
continuation of a „Jugend forscht“-project
After reading Bruno Lüth's project for "Jugend forscht" about thunderstorm centers in Göttingen and its surroundings" we decided to work on our own project. He noted that there are more centers over big settlements in a valley. We got the idea that this was manly influenced by the acid concentration as there is a higher acid concentrate over bigger cities caused by industries, emission and fires which could have an effect on the conductivity of clouds.

At first we made solutions out of water and lemon juice with a pH-value from 4.7 to 6. It took us quite a while to get what we wanted.


Using those solutions, an aerosol and a spark coil we tried to produce a thunderstorm cloud. We differed the gap between the two balls to check how the acidity of the little water drops would impact on the conductivity.

  back and                                                                                                                  front of the spark coil   

Because of the curved surface of the balls we did not have a good measuring point which meant that our measuring was quite imprecise. That's why we used a “Jakobsleiter” (Hörnertransformator).


Using this we still didn't find a regularity so we detected the pH-value again. Our wonderful solutions had turned from acid to lye. They were probably decomposed by bacteria as there were herbal ingredients in the solutions.

these naughty little bacteria =)

Mrs. Bokeloh-da Silva helped us to produce solutions out of sodium hydroxid and citric acid with a pH-value from 5 to 6 (Thank you very much!)

We repeated our experiment but unfortunately we still didn't get the results we expected. So we thought that the irregularity could be caused by the drops because they haven't got similar sizes. Using an inhalator we wanted to avoid this and produce our cloud with tiny drops which should be more like the actual situation of a cloud. But still there was no result. That's why we bought solutions with a ph-value of 4 and 7. The difference was so big that we thought we could note better results as our last solutions were very close.

                           the inhalator  and                                                                    the spark plug

Instead of the “Jakobsleiter” we used a spark plug to avoid creepages. Still there were no results which was very disappointing. So we sat together and tried to solve the problem.

But all in all we stepped in conclusion that there is apparently no relation between the acid concentration of clouds and the occurrence of lightnings.

by Lisa, Meentje und Julia  |  April 2010