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Growing Irradiated Bean Seeds

Description: What happens to seeds that are exposed to very high levels of radiation? Will they grow normally?

plant growth

 

 

 

 

 

 

 

 

 

 

 

 

Grade Level

5-12

Disciplinary Core Ideas (DCI, NGSS)

5-PS1-3, 5-ESS3-1, 3-5 ETS1-1, MS-ETS1-2, MS-ETS1-3, HS-PS4-4, HS-ESS2-3

Time for Teacher Preparation

To gather materials and set-up

Activity Time:

1-2 Weeks Minimum. Passive observations as beans grow.

Materials

Safety

Science and Engineering Practices (NGSS)

Cross Cutting Concepts

Objectives

The students develop a procedure to study the effects of radiation on mung bean seeds and other irradiated seeds. Students will observe and record data on the germination and development of the plants. Student data, results, and conclusions will be presented, supported, and defended by the students to the class.

Background

Irradiation is becoming increasingly more popular in the treatment of foods to kill bacteria, diseases and pests. A fear of radiation causes some people to believe that food that is irradiated becomes radioactive. The irradiated bean seeds in this experiment have been exposed to various levels of gamma radiation, but are not radioactive and are completely safe to handle.

You cannot tell how much radiation the seeds were given by looking at them. These seeds were harvested and irradiated after the plants were mature. However, you will be able to observe differences in the plants growing from these seeds. Each seed contains an embryo plant. When the gamma radiation passed through these seeds, it damaged some of the cells in the embryo. The greater the radiation, the more cells were damaged. Therefore, the resulting plants grown from seeds with greater exposures will show more abnormalities than those with lower exposures.


Teacher Lesson Plan:

Traditional

Split students into groups of four and give each group four sets of bean seeds (control; 50,000; 100,000; 150,000 rad). Have each group plant their seeds in separate pots and set up a table to chart and graph the growth of the seeds over the next couple of weeks. Students should record height and observations of their beans at least twice a week. Remind students to water their beans as frequently as needed in order to take care of their plants.

It might be helpful to stress that the beans have been irradiated, but are not radioactive.

Students may also grow the seeds in test tubes of water and plant them once they have germinated.

NGSS Guided Inquiry

Have students design an experiment to discover about how much radiation each of their seeds was exposed to.

Student Procedure

  1. Plant seeds into separate pots and water until the soil is moist. Alternatively, grow the seeds submerged in water inside of test tubes until they germinate and then pot them.
  2. Set up a data table to record height and observations of the bean seedlings. Observations should be made at least twice per week.
  3. Take care of your plants by watering them as frequently as needed.
  4. Graph data from your data table and deduce which seeds received which dose of radiation (control; 50,000; 100,000; 150,000 rad)
  5. Add a step to include listing the variables which must be controlled in this experiment.

Data Collection

Student Data Collection Sheets

Post Discussion/Effective Teaching Strategies

Questions provided on the Student Data Collection Sheets

Questions

  1. What happened? Why do you think the things you observed occurred? Were your observations and conclusions different from other students? Why? Who’s “right?”
  2. 100,000 rads or 150,000 rads is enough to kill a human. Did it kill all the plants? What do you think are some possible explanations?

Assessment Ideas

Differentiated Learning/Enrichment

Enrichment Questions

  1. If radiation increases on earth, what effects do you think it will that have on plant growth? On other organisms? On humans?
  2. What do you think happened to the cells of the irradiated Mung bean plants?
  3. Why do we use irradiation to prevent food from spoiling?

Further Resources

From Harvest to Home

Purchase Irradiated Mung Seeds through Ward’s Science (item #6730926)

Reference:

Los Alamos National Laboratory (1992). Detecting the Invisible: The SWOOPE Radiation and Radon Discovery Unit

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