Description: What happens to seeds that are exposed to very high levels of radiation? Will they grow normally?
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
1-2 Weeks Minimum. Passive observations as beans grow.
Science and Engineering Practices (NGSS)
Cross Cutting Concepts
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.
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.
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.
Post Discussion/Effective Teaching Strategies
Questions provided on the Student Data Collection Sheets
Los Alamos National Laboratory (1992). Detecting the Invisible: The SWOOPE Radiation and Radon Discovery Unit
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