Investigating Seed Dispersal

This lesson covers: 

  1. How to set up experiments to compare seed dispersal distances
  2. Important controls when investigating dispersal as a fair test
  3. Using a fan to assess the effect of wind on dispersal

Investigating dispersal by dropping fruit seeds

You can investigate how far different seeds disperse when they fall from height in your classroom.

Illustration showing a sycamore seed being dropped from a height above a marked point on the floor with a tape measure to measure dispersal distance.

Follow these steps:

  1. Obtain fruit containing seeds, e.g. sycamore seeds and horse chestnut seeds.
  2. Decide on a fixed height to drop all seeds from.
  3. Drop one seed at a time from this height directly above a marked point on the ground.
  4. Measure using a tape measure how far along the ground the seeds travelled from the drop point.
  5. Repeat at least three times for each seed type.
  6. Calculate the average dispersal distance.

Conducting a fair test

To fairly compare seed types, the following must stay the same:

  • The person dropping the seed.
  • Height the seed is dropped from.
  • Location of experiment (avoid draughts from doors/windows).

Using a fan to investigate the effect of wind

Adding a fan creates wind to test how it affects seed dispersal.

Diagram showing a fan, sycamore seed, tape measure, and mark on floor to investigate the effect of wind on seed dispersal.
  1. Position a fan a set distance from the seed drop point.
  2. Drop seed with the fan on at a constant speed.
  3. Measure and compare travel distances with fan on versus off.