• Using LEGO© to understand how photosynthesis works
    Using LEGO to understand how photosynthesis works

This lesson is appropriate for children ages 11 and up.

This lesson allows students to concretely experience the photosynthesis 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.

Lesson Plan

An interactive video called "Roots, Shoots, and Wood," with Dr. Kathleen Vandiver (inventor of this lesson), and produced by BLOSSOMS can assist you in teaching this lesson. A teacher's guide, written transcript, and class handouts can be found here. 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.


This lesson can be taught using the same LEGO bricks described in our Chemical Reactions and Understanding Air lesson. The  Atoms and Molecules Layout Mat shows the LEGO bricks we recommend for this lesson and the chemical reactions lesson. 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.

  • 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)
  • A container (box or clear plastic bag) is needed for each kit
  • Optional - about 20 connector pegs are needed for class for optional activity that builds cellulose molecules

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.

Supporting Documents

Laminated Mats and Posters



Video instructions to build the glucose molecule are in our TechTV collection: "Making Glucose Molecules."  An interactive video called "Roots, Shoots, and Wood," with Dr. Kathleen Vandiver (inventor of this lesson), and produced by BLOSSOMS can also assist you in teaching this lesson.

Student Worksheets

We are currently developing a new teacher's guide and student sheets. Note that the "Photosynthesis Student Key" found below serves well as a Teacher's Guide.


Teacher Resources

The teacher's guide is not yet ready. However, you may like to use this older version of LEGO Education's Teacher's guide:

Curriculum Standards

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 National Science Foundation 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.
Document Versions prior to June 2012

PDF icon 2009 Version - Reactants and Products
PDF icon 2009 Version - Atom and Molecules Layout Mat

Contact us if you would like to learn how to use the materials at our next workshop, or if you would like to inquire about a complete classroom set of materials including LEGO bricks.

LEGO®, the LEGO logo, and the brick and knob configurations are trademarks of the LEGO group, used here with permission. ©The Lego Group and MIT. All rights reserved.