CULTURING
PROTISTS
Introduction
The amount of liquid a bottle cap can hold may not seem like much.
But if you are a microorganism called a protist, a cap full of liquid is an
ocean. With lots of room to grow and reproduce, these tiny organisms
flourish in this microenvironment. Protists are a group of microscopic
organisms that show a lot of variety. Some are similar to animals, while
others seem more like miniature plants. In this experiment, you will
investigate the kingdom of Protista and use the Internet to help identify
the organisms that make it up.
Time Needed
50 minutes on day 1
50 minutes on day 2
50 minutes on day 3
What You Need
F plastic drinking bottle with cap (1 quart, 1.8 fluid ounces
F glass dropper
F microscope
F depression slide with cover slip
F lens wipe
F flat microscope slide with cover slip
F 400-milliliter (ml) beaker of dilute bleach solution
F 2 large, heavy metal washers
F 33 foot (10-meter) small-diameter nylon cord
[1 liter] or smaller)
(or 12-pound test line)
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CULTURING PROTISTS
F wooden dowel (0.8 inch [in.]) × 11.8 in.) (2 centimeters
[cm] × 30 cm)
F permanent marking pen
F light source
F access to water
F access to a pond
F access to the Internet
F science notebook
Safety Precautions
Please review and follow the safety guidelines. For outdoor
activities, wear high and heavy-soled shoes.
What You Do: Day 1
1. Wash and dry the plastic bottle and cap.
2. Using the marking pen, write your initials and the date on both the
bottle and its cap.
3. Create a water sampling device. To do so:
a. Loop one end of the cord through both washers; pull the cord
through the washers to a length of 11.8 in. (30 cm).
b. Wrap the 11.8-in. (30-cm) section of cord around the lower
portion of the bottle’s neck. Be sure the lid can still be screwed
onto the bottle. Tighten the loop around the bottle neck and
secure it with a knot (Figure 1).
c. With a firm knot, tie the other end of the cord to the center of
the wooden dowel. Wrap the attached cord around the dowel’s
center until the bottle and dowel meet. Screw the lid onto the
bottle. The water sampling device is now complete.
4. Carry your sampling device to the pond area designated by your
teacher.
5. Standing at the edge of the pond, unwind the cord from the bottle.
Holding firmly onto the dowel, toss the attached bottle into the
pond; allow it to bob and settle for a moment.
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CULTURING PROTISTS
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2 metal washers
nylon cord
plastic
soda bottle
Figure 1
Figure 1
6. Gently tug on the dowel; the washers will act as weights and tip the
mouth of the bottle into the water. Allow the bottle to fill with water.
Walker/Wood,
3, Figso
1(5.11-1)
7. Turn the wooden
dowel rod(JNEOF),
in yourVol.
hands
that it winds up the
cord and pulls the sampling bottle toward you.
8. Retrieve the bottle, screw on the cap, and wind up the cord.
9. When you return to the classroom, remove the lid from the bottle.
Set the bottle and lid aside for day 2.
What You Do: Day 2
1. Obtain a depression slide and clean it with a lens wipe.
2. Screw the lid firmly on the bottle. Tilt the bottle gently two to three
times to mix up the organisms and materials in the water.
3. Using the dropper, remove enough water to fill the bottle cap.
4. Using the tip of the dropper, gently swirl the water in the cap while
suctioning out a small amount. Place a drop of water on the
depression slide and cover it with a cover slip. Position the
depression slide on the microscope stage.
5. Focus the microscope on low power. Scan the slide and notice the
different kinds of organisms in your field of view. Pay particular
attention to the way organisms swim.
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CULTURING PROTISTS
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6.
Focus the microscope on medium power. Scan the slide again and
locate one organism that is moving. Watch its behavior for a few
seconds. Record your observations in your science notebook.
7. Remove the depression slide, rinse with water, and dry with a lens
wipe.
8. Use the dropper to transfer a drop of water from the bottle cap to
the flat slide and cover it with a cover slip. Position the slide on the
microscope stage and focus on low power. Change to high power
and focus.
9. Locate three different organisms. Draw each organism in your
science notebook. Be sure to include as many details as possible.
10. When complete, rinse the flat slide and cover slip with water and
dry them with lens wipe.
What You Do: Day 3
1.
2.
3.
Use the Internet to find photographs and drawings of different
protists.
Compare your sketches to those on the Internet.
Determine the names of the organisms you sketched. Record their
names in your science notebook.
Observations
1. Some protists are green. Why do you think this is so?
2. Did any of the protists you observed move? If so,
describe their motion.
3. The kingdom Protista contains several diverse species.
Name one characteristic that you think all protists have in
common.
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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