Pieter the Seed Eater; a device made of a tall pipe, base box and camera/computer to capture images of falling seeds.

Pieter the Seed Eater

Exploring the interface of ecology, mathematics and digital making

Seeds that are well adapted for wind dispersal have structures that increase drag, making them fall slowly so that they spend more time in the air. This means that they are more likely to travel further, increasing their dispersal distance. Being able to predict dispersal distances is fundamental to understanding how plant populations can spread across landscapes.

Seed terminal velocity is a key biological trait that influences a plant’s potential dispersal distance, alongside the height from which the seed is released, and the strength, direction and turbulence of the wind blowing at the time of release. Pieter the Seed Eater is a custom-made device that captures and process images of a falling seed, and calculates the seed’s terminal velocity. Pieter the Seed Eater was designed to measure the terminal velocity of pine (Pinus species) seeds from invasive trees in New Zealand, allowing us to assess the effect of slow and fast seeds on dispersal distances, and predict invasive species spread (Wyse et al. 2019).

The biosciences fall significantly behind other STEM subjects in employability statistics, yet the study and practice of biology is increasingly quantitative and computational. We want to highlight the interdisciplinary nature of biology by providing opportunities to wear some of the many different hats a bioscientist may wear: from traditional scientist to natural historian, coder, statistician, mathematical modeller, creative thinker and engineer.

The Seed Eater project has two aims:

  1. To increase knowledge of and access to the interface of computing and mathematics with biology, by developing teachers’ resources and activities for school-aged children.
  2. To create and develop a dataset of terminal velocity of wind-dispersed seeds.
Pinus nigra cone at Mount Barker, New Zealand.
Diagram showing how trigonometry is required to calculate the speed of a falling seed.

Calculating the speed of a falling seed as it passes through the field of view of a recording camera requires some trigonometry!

Below, you can find links to cross-curricular teaching activities and supporting resources, taking students from tree identification and seed collection, through the creation of their own Seed Eater to measure terminal velocity, to considering the implications of seed physiology and velocity on the potential spread of plant species across landscapes.

Each section of the teacher notes contains background information, suggested activities for groups and individuals, data recording sheets (printable and links to pre-formatted google sheets), and stretch activities for students to carry out in class or at home. These are provided as google slides under a Creative Commons license so that you can edit and adapt for your own educational needs, with links to the National Curriculum highlighted throughout. Accompanying interactive graphics are hosted online, and Python 3 code for the Seed Eater can be downloaded here or written from scratch (or in Scratch!), so that you can set up the device or let students engineer it from first principles. Students can also contribute their seed data to the Seed Eater project, which will be made available online in due course to all interested parties.

Illustration of ash seeds and leaves hanging from a branch.

Teaching Resources

Gif showing falling helicopter seed

Read the original research

Wyse SV, Hulme PE, Holland EP (2019). Partitioning intraspecific variation in seed dispersal potential using a low‐cost method for rapid estimation of samara terminal velocity. Methods in Ecology and Evolution, Volume 10, Issue 8, pages 1298-1307.

KidsLab podcast

Hear the Seed Eater creators Sarah Wyse and Pen Hollandtalk about Pieter with Sven Haiges, on the KidsLab podcast series at kidslab.dev

Link to google form to submit tree species and seed velocity data.

Link to google form to submit feedback about teaching resources.

Currently on hold due to Covid-19 - please check back soon.

Link to google form to apply for a Seed Eater kit for your school-age group (dependent on POLAR data).