A seed takes in water to swell and sprout — but the chemistry of that water matters. Five groups of 100 carrot seeds are set up in paper towel rolls, each watered with a different concentration of nitric acid. After 14 days, the pattern is clear: the group with no acid has the highest germination rate, the group with the most acid has the lowest, and more acid means fewer sprouts overall.

When rainwater turns acidic, it changes the chemistry of soil and water in ways that can stop seeds from sprouting. In this experiment, you set up five groups of 100 carrot seeds in paper towel rolls, each soaked in water mixed with a different amount of nitric acid — ranging from zero to eight milliliters. After 14 days, you unroll the towels and count how many seeds have germinated. The result is clear: more acid means fewer sprouts.