Arboretum begins new Monthly Explorations series for educators

October 5, 2015

Preparing Pigment Extract

Arboretum begins new Monthly Explorations series for educators

Preparing Pigment Extract

Learning how to mash leaves to release their pigments in alcohol.

On a windy and rainy Saturday morning, Boston Public School teachers gathered in the Hunnewell Building Lecture Hall at the Arnold Arboretum to learn about fall foliage color and seed dispersal through hands-on experimentation. During the first portion of the morning, teachers learned about leaf function, pigments, and how these change as the days get shorter. Next, they performed a leaf chromatography experiment to separate the carotenoids and chlorophyll pigments of four different types of leaves. The many thoughtful questions asked led to a lively discourse on science!

Materials for Leaf Chromatography

A variety of leaves were used when creating pigment extracts.

While these experiments were given time to work, participants switched their attention to a variety of wind-dispersed seeds. They began with a casual test of the flight patterns of several seeds, and discussed their results. Teachers were careful to make their claims based on evidence and defend their ideas based on their observations and prior knowledge. After closely observing seed packages from tulip, linden, ash, catalpa and maple trees, among others, teachers were asked to consider their structures when hypothesizing which seed would remain aloft the longest. Testing ideas involved a very high ladder and many tosses of seed packages into the air! Teachers marveled at the results, and discussed ways to record information, use technology, and extend these experiences in their own classrooms.

Samples of Wind Dispersed Seeds

A comparison of the various structures of wind dispersed seed packages.

Near the end of the two hour exploration, teachers returned to their chromatography paper strips and learned how to interpret the results. They left the session armed with pigment extracts, filter paper, fresh leaves, and bundles of seed packages. More importantly, teachers felt confident and energized to teach their students outdoors and also bring the outdoors inside for hands-on experimentation and learning.

Participate and learn more about our next Monthly Exploration.

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