
Research difference in effectiveness of different disinfectants on bacterial growth.
Have you heard that garlic powder is supposed to inhibit the growth of bacteria? Which do you
think would make a better disinfectant: a solution of garlic powder or a solution of bleach? What
are some noncommercial disinfectants used to kill bacteria can you see which is more effective
by measuring zones of inhibition on a culture plate.

How can your faucet save water?
One way to save water is to turn the faucet off while you brush your teeth. But did you know that
there are products that can help save water even while the water is on? Research how low-flow
faucets and aerators work to reduce the flow of water. Design an experiment to measure flow and
determine how much water can you save?

Do plants promote pesticide breakdown?
When pesticides are applied to protect crops, run-off of potentially harmful pesticides is a major
problem. Can water plants such as hardstem bulrush, common cattail, parrotfeather and smooth
scouring rush promote pesticide breakdown?

The effect of heavy metals on aquatic environments
Lead can be toxic, and you can get lead poisoning from eating or inhaling old paint dust. Lead is
called a heavy metal, and there are other sources of heavy metals that can be toxic, too. Silver,
copper, mercury, nickel, cadmium, and chromium are all heavy metals that can be toxic in
certain environments.
Design an experiment to find out if one common heavy metal, copper, can be toxic to an aquatic
environment. Using a copper sulfate pentahydrate solution that can be found in pet stores
examine what different levels of the solution do to different aquatic organisms such as Daphnia
(aka the water flea), small, cheap fish, live tubifex, aquatic plants like duckweed or elodea, or
algae spirulina.

Recycling Greywater: Can Plants Tolerate It?
One way to conserve water is to find safe ways to use it more than once. You can test whether
greywater (water that has been used for washing or bathing) can be used for watering ornamental
plants.

Oil Spills
No one can deny the devastating consequences of an oil spill on the local wildlife. Oil affects all
levels of the ecosystem, from plants to fish and birds.
 What happens to water plants if you add motor oil to their pot?
 What is the effect of motor oil on the health of a goldfish, or water insects?
7th grade GT Science Fair ideas
1





What happens to the barbs of a bird feather if they are dipped in oil? Can you test different
types of environmentally-friendly detergents for cleaning the bird feathers?
Can you test different methods of containing oil that has been spilled on water? What about
oil spilled on land?
How does it affect the soil, or plants that grow in the soil? Can you try to treat affected soil
with conditioners or detergents to improve the growth of plants after an oil spill?
Some detergents contain enzymes to break down oil and grease; research some of these
enzymes. Which enzymes are most effective for “cleaning” an oil spill?
The effect of temperature on dissolved oxygen
Dissolved oxygen is an important measure of water quality for aquatic life. In this project you
will use a test kit to measure the level of dissolved oxygen in water samples. Design an
experiment:
1. to measure dissolved oxygen in water samples at different temperatures, and
2. to determine the saturating oxygen concentration for water samples at different
temperatures.

Green detergents vs. conventional detergents, which is more toxic?
There is strong interest in "going green," including using products that cause less environmental
damage when they are disposed of. Design an experiment to compare the toxicity of "green" and
conventional liquid detergents using red worms as test organisms. Use different detergents
“green” and conventional at different concentrations to determine their effect on red worms.

Does the angle a baseball is hit with determine the distance the ball travels?
You will need to do a minimum of 5 angles with 50 trials each. You will need to keep the
amount of force used and the speed of the ball constant.

The curve ball, the more spin the better?
For this project, you'll use a baseball as a pendulum weight, studying the motion of the ball with
and without spin. Wrap a rubber band around the ball, and tie a string to the rubber band. Fasten
the string so that the ball hangs down and can swing freely. Mark a regular grid on cardboard,
and place it directly beneath the ball to measure the motion. You can also time the oscillations
with a stopwatch. Lift the ball along one of the grid axes, and let it go. Observe the motion and
record your results. Next, twist the string 50–100 times, and again lift the ball along one of the
grid lines and let it go. How does spinning change the motion of the pendulum? Try changing the
orientation of the seams of the ball: is the pendulum motion affected? What happens if you wind
the string in the opposite direction? Can your results help you explain how a pitcher throws a
curve ball? You will need to do a minimum of 50 trials for each different position. (Straight, 25
twists to string, 50 twists and 75 twists).
7th grade GT Science Fair ideas
2

The buoyancy of floating cylinders
A disk of wood will float face-up; that is, with its circular cross-section parallel to the surface of
the water. A long log of wood, however, floats on its side with the circular cross-section
perpendicular to the surface of the water. If you think about it, disks and logs are both cylinders.
Is there some intermediate length of cylinder that floats with the circular cross-section at a tilted
angle? Measure how the tilt angle of cylinders floating in water depends on the aspect ratio
(length/diameter) of the cylinder.
 Geology: The effects of environmental changes on soil microorganisms
Everything on our planet is linked by a giant recycling system called the biogeochemical cycle.
Learn how our planet recycles and reuses everything we need to support life by making a
miniature biosphere (Winogradsky Column). Test the response of soil microorganisms to
environmental changes (added carbon, sulfur, or nitrogen) in a closed system.

The effect of compression on volume
Did you ever notice the cool patterns around your footprints when you take a walk in the wet
sand at the beach? The pressure of your feet has effects far outside your footprints. Create an
experimental apparatus to investigate how the volume of wet sand changes under pressure.

Factors that affect the transfer of force through saturated soil
Earthquake damage can be intensified in areas that are subject to soil liquefaction. For example,
in these areas, soil movement may cause foundations to collapse, while structures in nearby areas
built on more stable soil or bedrock may escape relatively unscathed. Create a test to determine
whether soil additives (such as bark, leaves, Styrofoam peanuts) can reduce the tendency to soil
liquefaction.

Can mulch reduce garden water requirements?
Design a test to see if mulching a garden reduces water evaporation from soil

The effect of hydrogen peroxide on plant germination
Hydrogen peroxide (often used as a disinfectant) has also been approved for use in pesticides.
Create a project to investigate whether hydrogen peroxide has any effects on seed germination or
on roots of plant cuttings.
Find out the effect of different concentrations of hydrogen peroxide (H2O2) on the roots of plant
cuttings, and on seed germination.
7th grade GT Science Fair ideas
3

How does wind speed affect how quickly an object cools?
Have you heard the term windchill used before? Maybe on the TV weather forecast? The
windchill factor describes what happens to an object (like your body) when it is cold and windy
outside. As wind increases, heat is carried away from the body at a faster rate, driving down both
skin temperature (which can cause frostbite) and eventually the internal body temperature
(which, in extreme cases, can lead to death). Create a device to measure wind speed (an
anemometer) and determine how the wind speed affects the rate of cooling. Use an anemometer
and an infrared thermometer to determine how wind speed affects the rate of cooling of an
object. You can test different wind speeds on the cooling rate of objects.
Chemistry and Biochemistry
 Enzymes and chemical reactions
Create an experiment in which you extract the enzyme catalase from fresh (or frozen) liver, use it
to break down hydrogen peroxide, and test the effectiveness of catalase under different
conditions (extra acidity, basic conditions, or salty conditions, extra heating or freezing of the
catalase.)



“Enzymes are made out of protein and they speed up the rate of a chemical reaction by acting as a catalyst. A
catalyst provides the necessary environment for the chemical reaction to occur, which speeds up the reaction.
Certain catalysts work for certain kinds of reactions, in other words each enzyme has a particular type of
reaction that it can activate.”
“One source of enzymes is the liver, which needs to break down many substances in the body. Catalase is one
enzyme from liver that breaks down harmful hydrogen peroxide into oxygen gas and water. When this chemical
reaction occurs, you can see the oxygen gas bubbles escaping and causing the reaction to foam.”
Lactose intolerance
Explore the biochemical basis for lactose intolerance. You will add the enzyme lactase to
solutions containing the milk sugar lactose, and then test for one of the reaction products,
glucose, using glucose strips. What concentrations of lactase produce the least amount of
glucose? Can different things be added to solutions containing milk sugar that will reduce the
amount lactose/glucose?

Apple Juice enzymes
Pectinase is an enzyme that catalyzes the breakdown of pectin, a component of the cell wall in
fruits such as apples and oranges. In this project, you can apply pectinase to fruit under
controlled experimental conditions in order to investigate the enzyme activity of pectinase. You
can monitor the enzyme activity by measuring how much juice is produced under the various
experimental conditions. Some possible conditions to investigate are duration of enzyme
treatment, enzyme concentration, and temperature.
7th grade GT Science Fair ideas
4
 Bioluminescence
The marine dinoflagellate Pyrocystis lunula is a bioluminescent organism—bioluminescence is
the production of light by living organisms. But does this organism always glow, no matter what
the conditions, such as how much light there is? Investigate how altering this dinoflagellate’s
exposure to light and dark affects its bioluminescence. What other sorts of stress cause P. lunula
cells to emit light?

Alka-seltzer and gas production
o
o
Alka-Seltzer® tablets fizz when dropped into water, releasing carbon dioxide gas. Can you make AlkaSeltzer® fizz faster or slower by changing the temperature of the water? How big of a difference in the
rate of a chemical reaction can temperature make?
Can you increase the amount of gas produced or the amount of time it takes the tablet to dissolve by
changing surface area?
Copper, corrosion and acid




Measure the concentration of copper in the solutions using a test kit that provides more-accurate readouts
for copper concentration, such as the Hach Copper Color Cube Kit, item# 21822-00, 0-2.5 mg/L Cu. Visit
www.hach.com to find where you can buy this kit.
Devise a procedure to determine how the rate of copper corrosion varies with the pH of the water.
Test the copper concentration in the drinking water at your home using a copper test kit. Compare the
levels in the morning vs. later in the day after the system has been flushed out.
Devise a procedure for testing how salt (sodium chloride) affects the rate of corrosion of copper pipes.
Electricity
 Thermoelectricity
Everyone is familiar with the idea that electric current passing through devices can heat them up.
Most of us have used appliances like electric stoves, hair dryers, and toasters that are made
specifically for heating. We've also noticed that things that run on electricity get warm when the
current is turned on. Have you ever turned this relationship around and wondered if it is possible
to use heat to produce current?
Did you ever wonder if it is possible to cool things using electrical current? Research
thermoelectricity and design an experiment to determine how much voltage can be generated
between two junctions made of different conductive materials held at different temperatures?
Can you create a temperature difference between two junctions made of different conductive
materials by passing a current through them?
7th grade GT Science Fair ideas
5