Recreate Darwin’s Experiments In Your Backyard

I. Sink or Swim: Seeds in a Pickle

Darwin’s “seed salting” experiments were aimed at determining, first, how long seeds might retain their vitality after exposure to saltwater, and second, how long they can float versus sink in saltwater. He performed several versions of this experiment using seeds from many species, including garden vegetables, common weeds, and tropical plants.

A. Materials

Saltwater: prepare anywhere from 1 to 10 gallons (3.8 to 38 liters) of saltwater, depending on the scale of your experiment. We’re interested in approximating seawater. Like Darwin, you can readily make artificial seawater with commercially available salt and mineral preparations. You can purchase your salt mixture from any of the numerous online aquarium supply retailers (Instant Ocean® and Natural Sea Aquarium Salt Mix from Oceanic Systems, Inc. are less expensive brands), or from a local pet shop or aquarium supply store. Or, make your own with this recipe: