The Effect of Light Type on
Plant Growth
By Katra
Why is it important?
•
• Certain plants only
The environment
grow well in certain
around the world is
conditions, partly due
constantly changingto light. If the type of
due to that,the amount
light plants need to
and type of light plants
grow well is deterreceive changes too.
mined, more plants
Figuring out how this
would be able to grow
affects plants could
in more places,
help us learn to
improving the
stabilize the variables
agriculture as a whole.
and help plants grow.
Ultraviolet Light
• Wavelength- The
distance between two
“waves” of light
traveling through
space.
• UV Light has a very
short wavelength,
invisible to the human
eye.
• UV light is responsible
for sunburns.
Infrared Light
• Is on the other end of
the spectrum from UV
light, has a long
wavelength.
• Most objects emit
energy at infrared
wavelengths.
• Often invisible. Waves
are thermal.
Photosynthesis
• Plants turn sunlight,
water, and air, into
sugar,and convert it
into fuel by cellular
respiration.
• Formula
6H2O+6CO2--->
C6H1206+6O2, or 6
water molecules,plus 6
carbon dioxide
molecules,->
make 1 sugar
molecule plus 6
oxygen molecules.
Background Information
• Plants and light tie
tightly into one
another in the natural
world, because
without light plants
would die, and thus
without plants, over a
period of time species
all over the world
would die out.
How it relates to the Focus
• The main purpose of
this experiment was to
find how Ultraviolet
and Infrared light
affected the growth of
plants.
• The plants were
monitored under a
purple light, a red, and
in regular daylight.
• What was supposed to be
shown were the changes that
might have occurred to plants
receiving similar light in
nature.
Experimental Design Diagram
Title: The effect of different types of light on plant growth.
Hypothesis: If a plant receives light with longer wavelengths, then
it’s likely to grow better than a plant receiving shorter
wavelengths.
IV: Types of light (wavelengths)
Control:
Regular
Daylight
Infrared
Light
Ultraviolet
Light
8 Trials
8 Trials
8 Trials
EDD...
DV: Growth of Plant (centimeters)
General
Specific
Type of Plant
Bean Seedling
Amount of Light
8 Hours
Amount of Water
20mL
Amount of Seeds per
Pot
8
Amount of Soil
18 cm
Depth of Seed
8 cm
Procedure
•Put 18 centimeters of soil into 3 pots 20 centimeters tall.
•Then plant 8 pea seeds 8 cm deep and 3 cm apart from each
other.
•After that water each pot with 20 mL of water.
•Place the control by a window and the other two pots in the
basement, one under an Ultraviolet lamp, the other under an
Infrared.
•Water all plants with 20 mL of water every other day for six
weeks, starting Monday.
•Measure the plant growth for each seedling (in centimeters) once
a week for six weeks.
Derived Data Tables
Growth (cm)
Mean
Median
Range
Maximum
Minimum
Trials
Infrared
Data Weeks
11/14/01
11/21/01
11/28/01
12/5/01
12/12/01
12/19/01
Infrared
2.75
2.625
3.5625
3.5625
0
7
Ultraviolet
Control
2.8125
4.625
2.8125
4
6.5
4.625
6.5
4.625
0
0
7
7
Ultraviolet
0
2.1875
3.5625
2.625
2.75
0
0
6.5
3.625
2.625
2.8125
0
Control
0
1.1875
4
4.375
4.625
0
Graph #1
Graph #2
Explaining the Results/Trends
• In general, each plant
grew a particular way,
the control growing
the healthiest in the
long run, infrared
growing quickly and
green, but dying soon,
and ultraviolet
growing tall and thin,
pale and leafless.
Relating to the Environment
•The main idea was
to discover how
plants in different
environments
receiving different
amounts of light
would grow
differently, because
of their living
circumstances.
• In this experiment,
daylight
represented natural
“white light”, the
purple lamps the
ultraviolet light,
and the red lamp
the infrared light.
Possible Problems
• Bacteria might have
affected individual
plant growth.
• Light amount and
strength may have
varied.
• The distances seeds
were planted and
soil/air differences are
also possible errors.
Topics for Further Study
• Stars- what they’re
made of, how they
effect Earth and other
objects.
• Plants- learning in
more detail about how
they function and aid
our world.
• Light- Also learning
more about the
specific wavelengths
and types.
• Physics- Discovering
how particles
comprise the different
parts of our existence.
Overall...
• It was seen that plants that receive light in
the middle of the wavelength spectrum
(regular daylight) grow the best.
• Plants getting Ultraviolet light grow very
tall, but sickly, never very healthy and dying
quickly.
• And plants with Infrared light grow very
green and leafy fast, not growing very tall,
and also dying soon.
Bibliography
• UV Sun- imagers.gsfc.nasa.gov/ems/uv.html
• Visible/Infrared Orion- sofia.arc.nasa.gov/Sofia/
science/sofia_sci.html
• Water Plants- graphics.stanford.edu/courses/ cs448c-00-fall/
The End