Traits of Life: Exhibits

Experiment with water, temperature, and light to see what makes a seed come out of its shell.

What Do I Need?

o 3 black 35-mm film canisters, with lids
o water
o a paper towel cut into 1-cm x 4-cm strips
o 9 seeds each of cabbage, radish, and parsley

What Do I Do?

1. Add water to just cover the bottom of each film canister.

2. Insert three paper towel strips into each of the canisters, tipping the canister to moisten the strips.

3. Divide nine cabbage seeds among the three strips in one canister, nine radish seeds in the second, and nine parsley seeds in the third.

4. Put the lids on the canisters. Label each canister with seed type, date, and time. Check your seedlings every day. If they haven’t germinated within a week, try changing the temperature or moisture, or opening the canister lids to add light (just add one variable at a time), and record your changes.

What’s Going On?

While all seeds serve the same purpose—passing genes and new life from one generation to the next—most require unique conditions to do so. When the proper environmental conditions appear, the seed
germinates, or sprouts. Some seeds prefer darkness while others prefer heat to germinate, but they all need water. Water triggers germination, causing the seed coat to expand and rupture, allowing the plant embryo inside to emerge and resume growth and development.

Cabbage and radishes are fast germinators (usually within five to seven days) that need light and warmth to germinate. Parsley is notoriously difficult to germinate, and may take up to a month to sprout.

Experiment with different methods:

If your seeds don't sprout, try presoaking them in warm water overnight, storing them in a moist paper towel away from the light, or invent your own method to coax these recalcitrant seedlings out of their shell.

EXHIBIT SECTIONS : The Stuff of Life , Life Needs Energy , Making More Life , Change Over Time