Hello Sunshine!
Plants and their response to light
Overview
In this lesson, students will use container gardens to observe
the impact of different amounts of light on plant growth.
Standards (Microsoft
Word Document)
Materials:
- containers
- soil
- plants
- plant journal
- light meter (optional)
Background Plants capture light energy for use during photosynthesis,
the process by which they make their food. Plants can’t survive without
access to light, but the amount of light they need for healthy growth
varies by species. Some species have adapted to growing in full sun,
and they need to be exposed to full sun for most of the day; others adapted
to shadier conditions can thrive with only filtered sunlight.
There are two ways students can measure the amount of light available.
The first is duration – simply determining how many hours of full sun
a certain spot receives. The other way to measure light is to determine
the intensity or brightness of the light. Light intensity is measured
in terms of footcandles. A footcandle is the amount of light produced
in a totally dark space by one candle shining on a white surface
that
is 1 square foot in size, 1 foot from the candle.
For more background details to help your students with the questions
in the Laying the Groundwork section, Center
for Bioenergy and Photosynthesis.
Laying the Groundwork
Ask students:
- List the different elements plants need to grow
(light, air, water, nutrients and a place to grow).
Why do plants need light?
- Discuss photosynthesis with your class.
- Ask students to hypothesize what they think will happen if plants
do not receive enough light. Write down their predictions. How
can they test their hypotheses?
Exploration
1. Identify several three or more locations in
your schoolyard that receive different amounts of sunlight and
prepare
to measure duration and intensity. Students can determine how much
light each location receives by making hourly observations and
recording whether the location is in the shade or sun. For intensity,
they can use light meter to determine light intensity.
2. Plant a number of container gardens with identical plant
varieties. Include plants that prefer sun (such as vegetables)
and those
that prefer shade (such as impatiens or hostas). Place a different
container
in each location. If supplies allow, place more than one container
in each spot to increase scientific accuracy.
3. Record weekly observations
about plant growth in each location in garden journals. Ask students
to pay special attention to plant
height, leaf color, distance between leaves on the stems, and
number of flowers present.
4. Organize data into a chart or graph.
Discuss your results. Did the results support your hypotheses?
Did plant growth vary in the
different locations? Did different plants have different responses?
What do your results say about the importance of light for plant
health?
Making Connections
Locate locations around your schoolyard that would benefit from
container gardens such as the front entrance, a courtyard, or they
playground. Complete a site analysis of the locations and note space
and light available. Challenge students to create a garden design
with appropriate plants to place in these locations. If possible,
work as a class to choose the best designs.
- In addition to sunlight, plants can also grow under artificial
lighting. Try growing plants in a GrowLab and compare artificial light
versus natural light.
- Install a sundial
in your garden. Better yet,
plant a flower sundial where the flowers are planted according to
what time of
day they open, so that the blooming progresses around the circle
throughout the day. Here are some suggestions for flowers that
open at different times of the day from our Kidsgardening FAQs:
2 a.m.: convolvulus
3 a.m.: goatsbeard
4 a.m.: spiderwort, flax
5 a.m.: chicory
6 a.m.: morning glory, daylily
7 a.m.: African marigold
8 a.m.: fringed pinks
9 a.m.: marigold, tulip, and gazania
10 a.m.: California poppy
11 a.m.: sweet pea
12 noon: goatsbeard, wild daisy
4 p.m.: four-o'clock
5 p.m.: evening primrose
6 p.m.: moonflower
7 p.m.: sweet white nicotiana
8 p.m.: night-scented stock
9 p.m.: sweet rocket
Why Root for Container Gardens?
Choosing
Containers
Plants for Containers
Planting
and Maintenance
Lesson:
Container Garden Soil Investigations
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© 2009
National Gardening Association