Seed traps are a useful way to collect and study seeds. The traps collect seeds from a given area as they are travelling to their new destination. Scientists use seed traps to determine the distance seeds travel, and the method which they use. Simple household items can be used to construct your own seed trap. The following will tell you how to construct and use a seed trap and also poses questions which will help you to discover more within the world of seeds.
Materials needed:
For each team (three to six students):
1 51-centimeter (20-inch) circular piece of screen bent into
a bowl-like shape
(or a 50-centimeter [20-inch] plastic mixing bowl or similar container)
1 61-centimeter (24-inch) circular piece of cotton cloth
Duct tape or wire for attaching cloth to inside of screen (or bowl)
and for attaching screen (or bowl) to stakes
4 wooden stakes 5.1 x 5.1 x 61 centimeters (2 x 2 x 24 inches)
Choose a site -- Find an area or areas where several trees are located
next to
a cleared area
Time -- Each numbered item listed below will last between 20 minutes
to
an hour
INVESTIGATING
1. Initial observation -- Go to the study site. Spend 15 to 20 minutes
exploring
the site. Consider the following questions:
- How many different kinds of trees are there at the site?
- How would you describe each type of tree (its size, shape,
leaf shape)?
- What type of ground surrounds the trees?
- How would you describe the trees' seeds (size, shape, color)?
- Do you see any evidence of animals who have been near or on the
trees?
2. Deeper exploration -- Break into small groups and form a small seed
collection.
- Discover which seeds travel farthest by dropping seeds from
varying heights.
- Record and measure findings.
- Sort seeds by color, weight, shape, texture.
- Present findings to other groups.
3. Brainstorming -- Have a discussion within your group about which seeds
you
think would travel the farthest and why. What method of dispersal do
you
think each seed uses?
- Based on the information you have gathered, come up with one
answer
as a group to each of the above questions. You will test your answers by
doing an experiment using a seed trap.
4. Seed Trap Construction -- Attach the cloth to the inside of the bowl-shaped screen with duct tape. The wooden stakes should be placed around the bowl so it faces upward and can be attached with either tape or wire.
5. Seed Trap Experiment -- The first group will place its seed trap at
a
specific distance from a clump of trees (or forested area). The rest of
the
groups should place their traps one behind the other with that same
specific
distance between each one.
- The traps should remain in place for at least a week (more
depending
on the environment and the time of year); the cloth should be collected
and
replaced every week. Carefully examine the cloth for seeds.
6. Reflective thinking -- During the experiment, consider the following
questions:
- Why is it helpful for seeds to travel?
- How might the shape, size, or texture of a seed help it travel,
or keep it from traveling?
- How might seeds that only travel short distances on their own
reach
new locations?
7. Present findings -- Groups should present their work and findings to
each
other and be able to discuss the following questions:
- What types of seeds fall in your schoolyard?
- Which seeds are most numerous?
- Which seeds in your area travel the farthest?
- What traits do seeds that travel long distances have in common?
- What traits do seeds that travel short distances have in common?
- On what type of days (windy, rainy, etc.) did you collect the most
seeds?
- Consider the season in which you perform this experiment. Could
that be a reason for the amount or type of seeds you collect?
- This experiment and discussion questions was adapted from the Dragonfly article: "Every Forest Begins with a Seed" by Dr. David Gorchov, Miami University, Oxford, Ohio.