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Lesson Title: Living Clocks
May 11, 2012

Unit: Life Science - Plants

Grade Levels: 4-6

Connection To Curriculum: Science

Teacher Prep Time: 1 hour

Lesson Time Needed: 10 minutes daily over 6 days

Complexity Basic

Keywords: circadian rhythms, behavior, plants, adaptation


Four bean plants per group (purchase or grow in small pots from seed)
Source of natural sunlight
Fluorescent light (portable shop light or plant "grow light")

This lesson introduces students to the concept that many of the activities of living things occur in cycles of about 24 hours. The daily cycles are governed by internal "clocks," and internal clocks are cued by the environment but run independently.

Students will:
• Observe that some behaviors and functions of living organisms vary predictably every 24 hours.

First page of Living Clocks

Lesson Guide
Living Clocks Lesson
[92KB PDF file]



Professional Development Training Module for This Lesson

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Lesson Activities and Sequence
Outerspace to Innerspace/Sleep and Daily Rhythms Guide
Living Clocks - Plant leaf movement, page 6
In this activity students will observe that leaves will be dropped toward the stem very early in the day and fully extended (horizontal) later in the day, regardless of whether the plants are exposed to the sun or artificial light.
Keywords: circadian rhythms, behavior, plants, adaptation

National Standards:

National Science Education Standards, NSTA
Life Science
• Life cycles of organisms.
Science as Inquiry
• Understanding of scientific concepts.
• Skills necessary to become independent inquirers about the natural world.
Measurement and Data
• Represent and interpret data.


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