LEGO® Photosynthesis

This lesson allows students to concretely experience the photosyntheis reaction by building models of the reactants and products with LEGO bricks. Students construct a glucose molecule, simply by rearranging the atoms of carbon dioxide and water. They can go on to make chains of starch and cellulose. The lesson teaches students that most of the mass of a plant actually comes from the air and water, rather than from soil.

This lesson meets the following item of the Massachusetts State Frameworks for grades 6-8, Life Sciences (Biology) strand):

16. Recognize that producers (plants that contain chlorophyll) use the energy from sunlight to make sugars from carbon dioxide and water through a process called photosynthesis. This food can be used immediately, stored for later use, or used by other organisms.

It also meets the following AAAS benchmarks:

4c, grades 9-12, Processes That Shape the Earth:

Plants alter the earth’s atmosphere by removing carbon dioxide from it, using the carbon to make sugars, and releasing oxygen. This process is responsible for the oxygen content of the air.

5E, grades 6-8, Flow of Matter and Energy:

Food provides the fuel and the building material for all organisms. Plants use the energy from light to make sugars from carbon dioxide and water. This food can be used immediately or stored for later use. Organisms that eat plants break down the plant structures to produce the materials and energy they need to survive.

Energy can change from one form to another in living things. Animals get energy from oxidizing their food, releasing some of its energy as heat. Almost all food energy comes originally from sunlight.

And it meets the following NSF Content Standard:

Content Standard C, grades 5-8:

For ecosystems, the major source of energy is sunlight. Energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis. That energy then passes from organism to organism in food webs.

Lesson Plan:

An interactive video called “Roots, Shoots, and Wood”, starring Dr. Kathleen Vandiver (inventor of this lesson), and produced by BLOSSOMS (see below) can assist you in teaching this lesson. A teacher’s guide, written transcript, and class handouts can be found at blossoms.mit.edu.

BLOSSOMS (Blended Learning Open Source Science or Math Studies) is a collaborative initiative seeking to begin to develop a large, free repository of video modules for high school math and science classes created by gifted volunteer teachers from around the world, seeded initially by MIT faculty members and by partnering educators in Jordan and Pakistan.

Materials:

This lesson can be taught using the same LEGO bricks described in our Chemical Reactions lesson. The Color laminated LEGO Layout Mat and Atom Key shows the LEGO bricks we recommend for this lesson, the chemical reactions lesson, and other lessons we hope to post soon. We chose these bricks because they can be used to illustrate a number of chemical and biological concepts. Their colors match those commonly used in other chemical models. The layout mat can also be used as an easy clean up tool to check if students have all of their bricks.

Building blocks (such as LEGO) can be purchased from toy manufacturers or the LEGO.com website. Other colors may be substituted. For the photosynthesis reaction, ideally each team of students (2-4 students) should receive the following:

• 12 Black bricks 2X4 size ( model of carbon atom)

• 36 Red bricks 2X4 size (model of oxygen atom)

• 24 White bricks 1X2 size (model of hydrogen atom)

If this is too many bricks to purchase, the lesson can be done with half the number of bricks stated above in each student kit with a lesson modification. (6 Black bricks 2X4 size; 18 Red bricks 2X4 size; 12 White bricks 1X2 size) For more information, please view the lesson at blossoms.mit.edu.

Please contact us if you would like assistance in getting a set of LEGO bricks.

Other materials:

• Student instructional sheets:

Card A: Making Glucose Molecules

Card B: Making Starch Molecules

Card C: Making Cellulose Molecules

Layout Mat for Glucose Parts and Glucose Check Mat

Color laminated LEGO Layout Mat and Atom Key

• A container like a box or clear plastic bag is needed for each kit.

• One large paper (11X17 inches) for writing the photosynthesis equation is needed for each team. Alternatively use 2 paper sheets placed side-by-side.

• Optional –about 20 connector pegs are needed for class for optional activity that builds cellulose molecules. Not all groups will build them. These hold bricks together, back to back.