Science Fair Experiment: Chlorine Effects on Plants

Simple Comparative Experiment

1. Get 3+ identical small plants (same species, size).
2. Water each with a different source:
   • Plant A: Dechlorinated (filtered/distilled)
   • Plant B: Tap water (chlorinated)
   • Plant C: Heavily chlorinated (pool water)
3. Same light, same watering schedule (when soil surface dry).
4. Observe 3–4 weeks. Healthiest vs. sickest reveals chlorine impact.

Chlorine at drinking levels is usually tolerated; high concentrations damage roots and beneficial soil microbes.