K-12 Teaching and Learning From the UNC School of Education

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Learning outcomes

Students will:

  1. Collect and record data
  2. Use data to answer questions
  3. Observe transpiration

In this activity, your students will observe the process of transpiration. They will determine the rate of transpiration for one plant branch.

Teacher planning

Time required for lesson

2 days


  • a bean, or other plant, branch/stem
  • scissors
  • ruler
  • two test tubes (same size)
  • test tube rack
  • clock
  • graph paper
  • water
  • glass marking pencil


Teacher hints

  1. You can cut stems of plants yourself. However, if you use grown plants, you must plant the seeds (I use beans) two to three weeks prior to the lab activity.
  2. Make all measurements in millimeters.
  3. You may want to remind students of controlled lab setups to help with the question about the test tube in which evaporation occurs.
  4. Review the concept of slope to determine rate.
  5. Cut the plants with scissors and place them quickly into the test tube.

Student procedures

Day One

  1. Obtain two test tubes. Fill each test tube three-quarters full with water. Place both test tubes in a test tube rack.
  2. Follow the teacher’s instructions to obtain your plant stem.
  3. Place the plant stem so that it stands upright in one of your test tubes. Use the lab sheet to continue with activity.
  4. Use the glass marking pencil to mark the water level in each of the test tubes.
  5. Use a ruler to measure the height of the water in each test tube. Record these initial amounts in the lab table.
  6. Check the water height every ten minutes. Record the height of the water in each tube until the end of class.
  7. Follow the teacher’s instructions for clean up and where to place lab set up overnight.

Day Two

  1. Obtain the lab set up.
  2. Measure the height of water in each tube. Record height of each in the lab sheet from yesterday.
  3. Follow the teacher’s instructions for final clean up of material.
  4. Graph your results.
  5. Answer the lab questions. (Answers)
  6. Determine the rate of transpiration.


I usually give points for the following:

  • ten points for the table
  • twenty points for the graph (two lines)
  • ten points for the rate of transpiration
  • ten points for the lab questions

Supplemental information


A great and simple lab that allows students to see transpiration.

  • North Carolina Essential Standards
    • Science (2010)
      • Biology

        • Bio.4.2 Analyze the relationships between biochemical processes and energy use in the cell. Bio.4.2.1 Analyze photosynthesis and cellular respiration in terms of how energy is stored, released, and transferred within and between these systems. Bio.4.2.2 Explain...

North Carolina curriculum alignment

Science (2005)

Grade 9–12 — AP Biology

  • Goal 6: The learner will develop an understanding of the unity and diversity of life.
    • Objective 6.05: Examine the structure and function of plants and animals.
      • Analyze reproduction, growth, and development.
        • Patterns
        • Adaptations (e.g. alternation of generations).
        • Regulation as by hormones.
      • Recommended laboratory - Transpiration
      • Analyze structural, physiological, and behavioral adaptations.
        • Cell level.
        • Tissue level.
        • Organ level.
        • Interactions between levels of organization.
      • Recommended laboratories - Physiology of the Circulatory System, Animal Behavior
      • Identify responses to the environment.

Grade 9–12 — Biology

  • Goal 2: The learner will develop an understanding of the physical, chemical and cellular basis of life.
    • Objective 2.05: Investigate and analyze the bioenergetic reactions:
      • Aerobic Respiration.
      • Anaerobic Respiration.
      • Photosynthesis.