The Great Plant Debate
A Collaborative Activity
The goal of this activity is for students to have a classroom experience that parallels the process used by US and Russian scientists as they discuss, plan, and conduct joint science on the Russian Mir Space Station. Through this collaborative activity we hope to:
Plants are of great interest to space scientists because of their potential role in yielding insight into new medicines, in keeping the spacecraft air clean, in providing food and recycling wastes, and in helping keep the astronauts happy and healthy!
The complete set of activities can be spread out over three months; individual elements that take one to two weeks can be done in a stand-alone fashion.
PART 1Classrooms around the world discuss and design plant-growing hardware, using the Internet to debate the strengths and weaknesses of various approaches, and then compare with NASA designs and NASA expert guidelines.
Sep 22 - Nov 4: (NOTE: Extended deadline)
Nov 6 - Dec 23:
Constraints and Microgravity Guidelines
Size: All items must be contained within a 1-cubic meter box (1m x 1m x 1m)
Weight: Less than 25 kilograms. (Hint: Tell students that recent estimates show that it costs approximately $30,000 to launch 1 kg into orbit.)
Crew time: Limited to 10 minutes per day to check up on your plant box; remember the astronauts are extremely busy.
Power: 120 volts 10 amps available (not really what's available in space, but we want to keep it to what kids are familiar with); extra points if you devise an innovative approach to producing your own power.
Data/Computer Connection: Standard serial port available for uplink and downlink to your classroom on the ground (for the technologically gifted).
Water: Must be self-contained, within your weight and size limitations; extra points if you propose a system to utilize waste water from the crew.
Air: Drawn from the crew cabin, assume at 20 degrees centigrade. If you want it warmer, you'll have to provide the heat source (don't forget the heat from your lights).
Microgravity Guidelines (Things to Remind Students)
Water: In space, free water forms a sphere. Students can't just have the astronauts sticking their hands in and watering the plants with a bucket.
Soil or other media: All items MUST BE CONTAINED in space, meaning that the astronauts aren't going to be happy with bits of soil, dust, or vermiculite floating around the cabin. (In fact, it's strictly forbidden.)
Convection currents: Remind students that there are none, so without a fan, or some means to blow the air around, hot light bulbs tend to explode, and plants tend to wilt in their own waste gases.
Day/Night: In a typical orbit, sunrise comes every 90 minutes. Use sunlight in your proposed design if you wish, but remember that most of the crew's work area is not in direct sunlight and a 90-minute day/night cycle can wreck havoc with growth and flowering.
Pollination: Though we have flown bees and other insects in space, for this project, none will be allowed in the plant hardware.
FURTHER SUGGESTIONS FOR THE INITIAL PHASE OF THE PROJECT
To better understand and compare growing conditions for plants on Earth and in space, it works best to review what students know about how plants grow on Earth. Refer to these conditions as Earth-normal plant growth requirements.
DIRECTIONS TO STUDENTS
Think about how all types of plants grow on Earth, whether growing outdoors or in a specially controlled area such as a greenhouse. List all of the conditions you can think of that help keep plants healthy and grow to maturity.
Make a chart with three columns. Label the first column "Condition" and use one or two words to name the growing condition needed. Label the second column "Source." In this column name the source of that condition. For example, if light is named in the first column, you might put "sun" or "flourescent lights" as a source. Label the third column "How Helpful." In this column, jot down a few words telling how or why the condition helps the plant grow or remain healthy.
You will have 10 - 15 minutes to complete as much as you can on your own. Next, you will share your thoughts with a small group.
TO THE TEACHER:
After 15 minutes, move students into groups of three or five and instruct them to share their ideas. They should add to their individual lists the new ideas that others in the group had listed. Encourage students by suggesting that any group who can list nine or 10 conditions is exceptional and that eight is good. A list of six or seven is what most kids will come up with.
Allow the groups about five to eight minutes to share answers. Then, using a large sheet of butcher paper or poster board entitled "Earth-Normal Plant Growth Requirements," develop a class poster that will be posted throughout the remainder of all plant activities.
Possible answers: Light, temperature, water for roots, humidity (water in the air) for plant parts above ground, fertilizer, dirt, pesticides (good time to introduce the concept of organic gardening), people caring for plants (talking to and touching plants does make a difference??), carbon dioxide, prepared soil areas (gardens, fields, flower pots, etc.), farm equipment, gardening tools, power to run electrical equipment used in any way to help plants grow, monitoring equipment (computers, light meters, etc.)
TO THE TEACHER ON THE CONSTRAINTS AND GUIDELINES
Inside the space shuttle, in addition to serious concern for safety, everything must adapt to microgravity. The purpose of the Constraints Section is to help students transfer their thinking from Earth-normal growing conditions for plants, to what is normal in spaceflight, or space-normal growing conditions for plants. Remember that the shuttle and space station environments are microgravity environments; the Moon has 1/6 gravity and Mars has 1/3 gravity. Growing conditions for habitats on the Moon and Mars would be somewhat different. For this lesson, we focus on shuttle and station "space normal" conditions.
Discuss with students the term "microgravity." What are some of the differences they know microgravity makes for the astronauts' daily life in space? Many have seen TV coverage of shuttle flights or TV programming that demonstrates the weightlessness of microgravity. Help them apply those conditions to their own daily routine and what differences those would make in common activities such as brushing their hair, drinking water, etc.
Have students review the Earth Normal Growing Conditions list. Through small group work (use the same grouping that was assigned for Part I) have students decide which requirements are affected by microgravity. Have the groups discuss how and why they would be affected. Have each group select two of these conditions for explanation to the class. Each group should choose a spokesperson(s) for this oral reporting. As each group presents, discuss as needed.
How do different cultures negotiate working together in space? For example, how do you decide what language to use, what kind of food to eat, whose rules will be followed?
See Frank Salisbury's journal and biography on the S/MORE Team pages
See Tana M. Hoban-Higgins, Ph.D. discussion of day/night cycles and circadian rhythms
See Gregory D. Goins, Ph.D.'s biography and journals on the S/MORE Team pages
See Why Study Plants?, Article by Sarah Wyatt, Ph.D.
See Why Grow Plants in Space?, Article by Bonnie McClain and Tom Scott
Discussion of Space Biology and the SVET greenhouse on Mir