Many plants contain dyes that change color depending on the pH value. The H2O mach’s bunt school competition has set out to answer which plants give the most colorful palette of pH indicators by inviting pupils to isolate dyes from plants and use them to measure the pH of water samples.
A jury headed by Professor Peter Menzel, University Hohenheim, Germany, decided out of more than 1,000 entries. The first prize was awarded to the Mittelschule Flöha-Plaue, Germany, for using aquilegia giving a palette of 12 different colours and the Johannes-Vincke Schule, Germany, for their very exact pH measurements and documentation of their experiments.
