Light is Life

Lesson Overview
Goals
- Students will be able to explain how photoreceptors function causing plants to follow light.
Outcomes
Teach the Teacher
Tools & Materials
- Seeds or starts
- Individual containers
- Various light sources
Activity
Timelapse videos of plants following a light source are simply awe inspiring. The movements in real time are subtle and are often unnoticed in the garden. But when the process is accelerated in a time-lapse video it’s clear to see just how plants chase the daylight.
The purpose is to capture as much of the sun’s energy as possible for the critical photosynthetic process. Light is irresistible to plants and their appetite for it would seem insatiable. So how long does it take a plant to actually shift its position in real time? And do plants follow all light sources with equal vigor? Are all light sources equal or are some sources better than others?
Experiment with the sensitivity of photoreceptors in young plants. Using a sample of different plant varieties change the location of the light source and document how long it takes for the plant to adjust toward the light. Try the same experiment with different light sources to determine if the type of light has any bearing on photosensitivity. Draw a conclusion about which light source is most sought after by plants in your experiment using sunlight as your baseline.
Related Lessons
Give the Advanced lesson a try now that you’ve completed the Intermediate Lesson! Or revisit the Beginner Lesson as needed.
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