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More Than a Walk in the Park?: Demonstration Carts Personalize Interpretation

Number 18 - July 1999

S. Mintz & S. Rode

A Common Dilemma

'Why don’t we have this kind of tree in Missouri?' a young visitor wonders, after discovering that biodiversity is greater in the tropics.

'How can "dirt and gravel" purify water?' another ponders as she stares at a terrarium ‘ecosystem’.

'I told you! It’s the people who are having all those babies who are destroying our environment,' a third exclaims after watching a counter tick off increases in population and dropping acreage of rain forest.

Garden staff wince as they overhear statements like these. As educators, we are pleased that visitors are thinking. At the same time we are chagrined to hear their erroneous conclusions.

Visitors' questions often require complex answers. The very best exhibit can only provide so much information. And the lesson the visitor takes home may not be the one intended.

As botanical gardens assume a greater role in helping the public make sense of global environmental change, they are increasingly challenged to help their visitors understand complex conservation issues. While their plantings can present biodiversity, and their collections may exhibit fascinating adaptations, plants cannot speak for themselves. How can we engage visitors, and answer their questions, while using the power of these collections?

Eco-Cart demonstrations at Missouri Botanical Garden successfully address this challenge. These demonstrations use several approaches that are known to have great power in stimulating learning:

  • live presenters talk with visitors
  • visitors participate in the presentations
  • the content of each presentation is linked back to visitors' daily lives
  • visitors leave with a memento of their contact.

Bringing the Message Home

In 1990, Missouri Botanical Garden began renovating exhibits in its conservatory complex to help visitors understand the biomes represented in conservatory plantings. The garden also sought to help visitors understand the global processes and local conditions that determine the health of our environment in its new Brookings Interpretive Center.

The setting that was to be created was dramatic. As visitors entered the center from the Climatron, they would confront a startling sight. A life-size bulldozer would roar aggressively in front of a backdrop of charred tree stumps. The sight would be disorienting, even discouraging, after a walk through lush rain forest. Behind the bulldozer, textual and interactive exhibits would present ideas the silent plants in the conservatory could not explain.

Because the best interactive exhibit cannot be as engaging as a well-prepared, enthusiastic live human being, the garden also sought funding to create a series of short, live demonstrations that would actively involve visitors in exploring a single science concept. The McDonnell Foundation generously funded the development of informal Eco-Cart demonstrations and their associated props, for use with both public and school audiences, in a small amphitheatre within the center.

Linking Science and Environmental Action

The McDonnell Foundation supported this project to increase public understanding of how ten major science concepts are linked to modern environmental problems. All these concepts fall well within the natural subject matter for botanical gardens. The topics range from photosynthesis and decomposition to chemical reactions and energy. Some are readily illustrated; others are very abstract-such as energy. Each relates to a pressing environmental quality issue such as sustainability of food supplies; availability of metals, air pollution, and availability of fuel supplies. (Table 1)

Table 1: Linking science concepts to environmental problems

Science Concept

Environmental Problem/Understanding


Plants are the base of all life on earth and must be protected


We must recycle what we use because nutrients recycle

Food chains

All life depends on energy from the sun. When we eat meat we eat food that requires more energy in its production

Plant products

We all depend on the diversity of plants in the tropical rain forests.


What causes loss of species?

Water cycles

We must avoid polluting the water we will reuse one day or clean it


We must conserve energy because our fuel supplies are limited

Chemical reactions

Burning fossil fuels affects the health of people far away


The health of everything and everyone on life is interlinked


The rate of change in many places threatens to drive many species extinct

Instructional Sequence

Each Eco-Cart demonstration has been designed to use a learning cycle model of instruction, presented in the context of a skit or story that will capture visitors' imaginations. The outline for each Eco-Cart demonstration includes the following elements:

  • an intriguing demonstration to build visitor interest
  • a storyline that helps visitors see how this scientific process or phenomenon affects their lives
  • a narrative device in the skit that helps visitors participate throughout the lesson
  • a sequence for introducing new concepts
  • an environmental application of the science concept
  • a physical memento or handout to carry home.

The demonstration on photosynthesis, for example, opens with the presenter obtaining an assignment to perform some industrial espionage. She is enlisted to find out how sugar is being produced in a leaf. When she hands out sunglasses as a disguise, the audience knows that they are invited to help her. She opens an envelope filled with molecules of carbon dioxide, water, and oxygen and asks the group to put them inside a cloth "leaf". When another pocket in the leaf is zipped open, there are glucose molecules. After this, participants look at microscope slides showing stomates and chloroplasts, and watch her complete some experiments with indicators to show that plants use carbon dioxide, and produce oxygen. Participants take home a sugar packet, as a reminder of what plants make for us.

Hands-on Approach

As each Eco-Cart demonstration was scripted, staff considered ways that visitors might actively participate. Could they hold a worm during a presentation on decomposition? Could they physically sort food products that come from plant and animal sources for themselves? Could they feel waste heat by clapping vigorously during a presentation on energy? Whenever the staff could imagine a simple way that visitors might do, instead of the presenter, this mode of presenting a concept was selected.

This active instructional style was selected because humans rely heavily on all our senses to ‘gather’ information. We know that adults like ourselves, and as much as children, find touching real objects highly engaging. Garden visitors enjoy feeling the texture of a hairy sugar palm as much as they do lingering over the sight of a blossoming rose. By encouraging them to touch, smell, and handle objects we can open minds and stamp the messages we deliver into visitors’ memories.

Audience-Driven Decisions

Because the Eco-Cart Demonstrations serve a very diverse audience, the demonstrations avoid technical language and assume visitors have little prior knowledge of their topics. We want families, foreign visitors, and long-standing members all to find the presentations of interest. Furthermore, we want presentations to enhance, not detract from the quality of visits to the garden. Garden staff therefore scripted each informal presentation to last no more than 15-25 minutes. Presentations are scheduled in periods when visitation is highest, in order to serve the largest possible audience.

Visitor Response

And how effective have the Eco-Carts been in engaging visitors in learning? Visitors are so attracted to the props displayed on the portable carts that it is hard for the demonstrators to leave their posts! The visitors raise all types of questions, both in these informal interactions and the compact presentations. Clearly, the combination of clever stories, intriguing objects, and a personable presenter succeeds in engaging visitors' interest.

The steadily increasing attendance indicates that word of mouth is beginning to draw participants. This indicates that the demonstrations will help Missouri Botanical Garden achieve another goal we share - to encourage visitors to return.

In the initial months of each presentation, the garden has adjusted each script to the knowledge most visitors display and to remove logistical problems. In the months ahead, the garden will begin to more rigorously measure how well the demonstrations build understanding.


Using a story with a scientific theme and a 'take-home' ecological message makes the Eco-Cart demonstrations very effective. Television shows often rely on gimmicks that are dangerous or difficult for viewers to duplicate, whereas the Eco-Carts use simple experiments and props to do the same. Eco-Cart demonstrations can readily be replicated at any garden that wishes to engage its visitors in active learning.