THERMAL POLLUTION
AFFECTS SEED GERMINATION
Introduction
Fish, like many living things, depend on the oxygen in their environments
to survive. Although water molecules are made up of oxygen and
hydrogen atoms (Figure 1, stick model of a water molecule), it is the
oxygen dissolved in the water that supports life. Plants depend on
oxygen the same way that animals do. Seeds of plants require oxygen to
begin their new lives. Thermal pollution, a process in which water in an
ecosystem is heated, can cause water to lose its dissolved oxygen.
Wastewater from power plants and industries can elevate the
temperatures in surface water and groundwater nearby (Figure 2). When
this happens, oxygen molecules take in energy and quickly escape into
the atmosphere. With the loss of oxygen, organisms are affected. In this
activity, you will design an experiment to find out how thermal pollution
affects the germination of peas.
hydrogen
oxygen
Figure
Figure 11
Walker/Wood, (JNEOF), Fig 1(6-5-1a)
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THERMAL POLLUTION AFFECTS SEED GERMINATION
Figure 2
Time Needed
40 minutes on day 1
15 minutes on days 2 to 6
30 minutes on day 7
What You Need
F hot plate
F hot pads
F 250-milliliter (ml) beaker
F permanent marking pen
F 2 petri dishes with lids
F 8 Alaskan pea seeds
F ruler
F access to water
F 50-ml graduated cylinder
F shoe box with lid
F science notebook
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THERMAL POLLUTION AFFECTS SEED GERMINATION
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Safety Precautions
Be careful when working with a hot plate. Please review and
follow the safety guidelines.
What You Do
1. Your task is to design and perform an experiment to find out whether
or not thermal pollution has any effect on the germination of peas.
2. You may use any of the supplies provided by your teacher, but you
do not have to use all of them.
3. Before you conduct your experiment, decide exactly what you are
going to do. Keep these facts in mind:
Your experiment should have an hypothesis.
Your experiment needs a control.
Your experiment should yield measurable results.
You need to collect data from your experiment on a regular basis.
4. Write your hypothesis in the space provided on the data table.
5. Write the steps you plan to make (experimental procedure) and the
materials you plan to use (materials list) on the data table. Show your
hypothesis, procedure, and materials list to your teacher. If you get
teacher approval, proceed with your experiment. If not, modify your
work and show it to your teacher again.
6. Once you have approval, assemble the materials you need and
begin your procedure.
7. Collect your results on a data table of your own design.
8. Create a line graph that portrays your data. Place the independent
variable on the x-axis and the dependent variable on the y-axis. Be
sure to give your graph a name.
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THERMAL POLLUTION AFFECTS SEED GERMINATION
Data Table
Hypothesis
Your
experimental
procedure
Your
materials
list
Teacher’s
approval
Observations
1. What were you investigating in this experiment?
2. Was your hypothesis correct?
3. What is the independent variable in this experiment?
What is the dependent variable?
4. Describe your control.
5. What results did you draw from this experiment?
Want to Know More?
See Our Findings.
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SAFETY PRECAUTIONS
Review Before Starting Any Experiment
GENERAL
• Always obtain your teacher’s permission for experiments performed
at school, and your parent’s permission for experiments performed
at home, before attempting any experiment.
• Read all instructions for an experiment before starting the
experiment, and follow the directions exactly as they appear in
this volume.
• If an experiment requires adult supervision, do not perform the
experiment unless you have an adult supervising you the entire
time you are performing the experiment.
• Wash your hands before the start of and after each experiment
you perform.
• Keep your work area clean.
• Never eat or drink while performing an experiment. Never taste a
substance used in an experiment unless you are told that it is safe
to do so.
• Be aware of the location of safety equipment you may need in an
emergency, such as running water, an eyewash if you are at school,
and a fire extinguisher.
• If you are going outside, make sure you have permission to go
from your teacher and parent. Take a buddy with you, and dress
appropriately for the weather. Make sure you or someone who
accompanies you is familiar with the area, and bring along a firstaid kit in case of emergency.
• Never look directly into the Sun.
CHEMICAL SAFETY
• Always wear goggles when working with chemicals, such as acids
and bases, and near heat sources like flames. If at all possible,
avoid wearing contact lenses when working with chemicals.
• If any substance gets into your eyes, notify an adult (e.g., your
teacher or parent) immediately, and flush your eyes with running
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SAFETY PRECAUTIONS
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water for at least 15 minutes. Do not mix chemicals unless you are
told to do so by a teacher or parent.
• Never touch, taste, or smell chemicals unless instructed to do so.
• Keep chemicals in closed containers when they are not in use.
• Dispose of all chemicals properly. Do not pour any chemicals or
solids down the drain unless instructed to do so.
• Use safety gloves and a plastic apron when handling chemicals. If
any chemicals spill on your skin, rinse the affected area with
running water for at least 10 minutes, and notify your teacher or
parent immediately.
• Take precautions to avoid spilling chemicals. If a chemical spills on
any surface, notify your teacher or parent immediately to assist
with clean-up.
• Exercise caution when using sharp instruments such as knives or
scissors. Always cut away from yourself, not toward yourself. If you
cut yourself, notify your teacher or parent immediately.
GLASSWARE
• Clean glassware when you are finished with the experiment.
• Be careful when using glassware. If a piece of glassware breaks,
have an adult assist you in clean-up to avoid injuries from broken
glass. Never use broken or damaged glassware.
FIRE SAFETY
• Do not heat glassware that is not completely dry. Do not pick up
hot glassware without heat-resistant gloves or tongs.
• When heating glassware, keep it away from yourself and from
others.
• Do not heat anything unless instructed to do so by a teacher or
parent.
• Do not heat substances in a closed container.
• After an experiment, make sure that all heating sources are off
and that all flames have been put out.
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SAFETY PRECAUTIONS
• Do not reach across such heating sources as flames.
• If you have long hair, tie it back, out of the way. Do not wear
clothing with loose sleeves, scarves, bows, ties, or anything else
that may hang into a fire. Do not wear long earrings.
ELECTRICAL SAFETY
• Do not touch electrical equipment when your hands are wet.
• Do not plug several electrical devices into one outlet or use an
extension cord.
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