Plants in Space

Stems grow up. Roots grow down. At least, that's what happens on Earth. In the microgravity environment of the International Space Station (ISS), things work a little differently. Plants do not sense "up" or "down," so their growth can be erratic. Astronauts on long-distance space flights will rely on plants as a food source, so it is important to learn how to make plants grow normally in the absence of a dominant gravity direction.

The Plants in Space student investigation focuses on the growth of roots in microgravity. The plants, Brassica rapa (Wisconsin Fast Plants), will be grown in a transparent medium on the ISS so that their root development can be studied and compared to that of plants grown in normal gravity in classrooms on Earth.

Light affects the direction in which plant roots grow. Typically, roots grow toward light sources with strong red wavelengths, and away from light sources with strong blue components. These responses are referred to as phototropic (plant growth responses to light). The Plants in Space investigation will examine whether white light with a strong blue component will cause plant roots to grow into their growth medium, even without gravity's directional clues "telling" them to do so.

Using similar chambers and the same plants on Earth, students will make daily observations to compare plants in normal gravity with those in microgravity. Images of the space plants will be made available for examination and measurement on the BioEd Online website (www.bioedonline.org). Four, 5-day planting experiments will be conducted during fall 2011. The first experiment is scheduled to begin September 19.

BioEd Online is the place to go for student investigations on the International Space Station. By registering your home school, museum or organization, you will receive free access to the Plants in Space educator guide and all the flight images and videos from the investigation. Many additional resources are available, and the ISS images and videos will be archived, so you can repeat the investigation whenever, and as often as you like.

Hourly images of the plants are available here on BioEd Online (see photo gallery below), and also as downloadable PowerPoint files. The free Plants in Space guide contains instructions for setting up ground-based plant chambers and helping students to design their own plant investigations. Students are encouraged to compare their Earth-based plants to photos of plants growing in space.

From 2011, A Framework for K-12 Science Education, National Research Council

SCIENTIFIC AND ENGINEERING PRACTICES

• Asking question
• Developing and using models
• Planning and carrying out investigations
• Analyzing and interpreting data
• Using mathematics, information and computer technology, and computational thinking
• Constructing explanations
• Obtaining, evaluating, and communicating information

PHYSICAL SCIENCE

Types of Interactions
Grades 3-5
• Electric, magnetic, and gravitational forces between a pair of objects do not require that the objects be in contact
• The force of gravity of Earth acting on an object near Earth's surface pulls that object toward the planet's center.
Grades 6-8
• Gravitational forces are always attractive.
• There is a gravitational force between any two masses, but it is very small except when one or both of the objects have large mass—e.g., Earth and the sun.

Conservation of Energy
Grades K-2
• Sunlight warms Earth's surface.
Grades 3-5
• Light transfers energy from place to place. Energy radiated from the sun is transferred to the earth by light.
Grades 6-8
• The path that light travels can be traced as straight lines.
• A wave model of light is useful for explaining brightness, color, and the frequency dependent bending of light at a surface between media (prisms)

Energy in Chemical Processes and Everyday Life
Grades 3-5
• Plants capture energy from sunlight.
Grades 6-8
• The chemical reaction by which plants produce complex food molecules (sugars) requires an energy input (i.e., from sunlight) to occur.
Grades 9-12
• The main way in which that solar energy is captured and stored on Earth is through the complex chemical process known as photosynthesis.

Electromagnetic Radiation
Grades K-2
• Objects can be seen only when light is available to illuminate them.
• Very hot objects give off light.
Grades 3-5
• A great deal of light travels through space to Earth from the sun and from distant stars.
• An object can be seen when light reflected from its surface enters the eyes; the color people see depends on the color of the available light sources as well as the properties of the surface.
Grades 6-8
• The path that light travels can be traced as straight lines.
Grades 9-12
• Electromagnetic radiation (e.g., radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons. The wave model is useful for explaining many features of electromagnetic radiation.

LIFE SCIENCES

Structure and Function
Grades K-2
• Plants also have different parts (roots, stems, leaves, flowers, fruits) that help them survive, grow, and produce more plants.
Grades 3-5
• Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior, and reproduction.
Grades 6-8
• In multicellular organisms, the body is a system of multiple interacting subsystems and groups of cells that work together to form tissues and organs that are specialized for particular body functions.
Grades 9-12
• Feedback mechanisms maintain a living system's internal conditions within certain limits and mediate behaviors, allowing it to remain alive and functional even as external conditions change within some range.

Growth and Development of Organisms
Grades K-2
• Plants and animals have predictable characteristics at different stages of development.
• Plants and animals grow and change.
Grades 3-5
• Plants and animals have unique and diverse life cycles that include being born (sprouting in plants), growing, developing into adults, reproducing, and eventually dying.
Grades 6-8
• Plant growth can continue throughout the plant's life through production of plant matter in photosynthesis.
Grades 9-12
• In multicellular organisms, growth occurs via a process called mitosis: a fertilized cell divides successively into many cells.
• Cellular division and differentiation produce and maintain a complex organism, composed of systems of tissues and organs that work together to meet the needs of the entire body.

Organization for Matter and Energy Flow in Organisms
Grades K-2
• Plants need water and light to live and grow.
Grades 3-5
• Animals and plants alike generally need to take in air and water, and plants need light and minerals.
• Plants acquire their material for growth chiefly from air and water and process matter they have formed to maintain their internal conditions (e.g., at night).
Grades 6-8
• Plants use the energy from light to make sugars (food) from carbon dioxide from the atmosphere and water through the process of photosynthesis, which also releases oxygen.

Information Processing
Grades K-2
• Plants respond to some external inputs (e.g., turn leaves toward the sun).
Grades 3-5
• Different sense receptors are specialized for particular kinds of information.

Interdependent Relationships in Ecosystems
Grades K-2
• Plants depend on air, water, minerals (in the soil), and light to grow.
• Different plants survive better in different settings because they have varied needs for water, minerals, and sunlight.
Grades 3-5
• Organisms can survive only in environments in which their particular needs are met.