We already suggested some basic microbiology experiments on our bread mold science project page.
This 7th grade science fair project experiment is a little bit more
complex. You're going to study how microorganisms react to temperature
stress. Which conditions they can survive better - heat or cold?
Yeasts are easily available, safe and easy to handle model organism for
this experiment.
You'll need
yeasts
sugar
coca-cola bottles (or other fizzy drinks
bottles)
balloons
Here is experiment outline:
Prepare 6 samples of yeasts. Use
the same amount of yeasts and water for each sample. Do not add sugar
to the yeasts solution.
Wait for 5-10 minutes for yeasts to
activate.
Put
two samples in the refrigerator and freeze them. Unfreeze one
in
few minutes after water is completely frozen, leave another one in
refrigerator for 24 hours.
Put 3 samples in hot water
(60C). Keep them in hot water for 5 15 and 30 minutes. Bring
samples back to the room temperature.
It's not necessary to prepare all the
samples simultaneously.
The last sample is your control sample.
Add sugar solution to the
control sample and measure it's activity by measuring the amount and
rate of gas production.
After temperature treatment add sugar to
the experimental samples and measure the amount and rate of gas
production.
Paper chromatography method allows you to separate different components
from a mixture. For example you can check if colored markers are made
of one color ink or mixture of different inks. This project
is easy to
do at home. Experimental part of the science project will take a few
hours, or less if everything is going just right. All you need is
coffee filters, solvents (most of them are used for cleaning) and
colored markers to separate. Read more about separating components of
the black water marker using paper
chromatography.
This 7th grade science
fair project is an example of basic study of chemical kinetics.
It's on of the fun science projects that you can easily complete in 24
hours.
The
goal of the project: to study dependence between temperature and the
rate of a chemical reactions. It's well known that generally reactions
run faster as temperature increases but is it a linear dependence? Is
this dependence the same for all chemical reactions?
It's easy to find out.
Constants: volume of reagents, physical state of the reagents, reagents
interface.
Variables: temperature.
You'll need
Tablets of alkaseltser.
White sugar cubes.
Thermometer (thermometer should be able
to measure temperature in 0C-100C range).
Water.
Pan.
Stove.
Spoon.
Glasses.
Fridge.
Procedure:
You'll
need to measure the rate of the reaction at different temperatures for
the different reagents. We suggest to use 10 degrees span in
temperature
between samples with lowest temperature ~1C degrees and
highest
temperature ~99C degrees.
For each temperature sample.
Put
a tablet of alkaseltser in the glass of water. Measure time needed to
fully dissolve the tablet. Measure water temperature change.
Put
a cube of sugar in another clean glass of water with the same water
temperature. Stir water with the spoon (make sure that
the stirring is the same in all samples). Measure time needed to fully
dissolve the sugar. Also measure temperature change in the sample.
Repeat this procedure for all temperature samples.
Build the graphs.
Does
curves for alkaseltser and sugar look the same? How does temperature
affect
the speed of the reaction? Is the change of the temperature
the same for both
substances?
Different
materials have different insulation properties. Knowing this properties
is important for engineer and architects. Proper insulation of the
house can decrease heating energy costs and help to protect our
environment. Make a hypothesis which material available at
home
or in craft shop would work as best insulator. You can try to invent
your own insulation material.
To test insulation properties
you can use two plastic containers with lids - larger and smaller size.
Fill small container with ice close it and put it in the middle of
bigger container filling the gap with insulation material.
Check
the ice in the small container regularly. Measure the time it took ice
to fully
melt. Then repeat procedure with another insulation material. You can
repeat trials for each material several times so your data are more
representative.
This would make an easy and fun 7th grade science fair project. It's
simple, cheap and can be compete in 24 hours.
Can organic pigment provide better pH measurements than commercial
indicator paper?
Create your own pH indicator from the red cabbage leafs and compare it
sensitivity to the sensitivity of Hydrion Paper.
To do this science project you'll need
Few fresh leaves of red cabbage.
"Hydrion Papers" - you can buy it in
garden shop or order online.
Vinegar.
Baking Soda.
Alkaline surface cleaners (check your
kitchen chemicals or local supermarket, they have many brands)
Working
with acids and alkaline may be dangerous. Try to avoid direct contact
of this substances with skin. Wear protective goggles. Never swallow
them! Ask adults for help!
Procedure:
Cut red cabbage leaves into small pieces. Put them in a jar.
Fill the jar with boiling water and leave for half of hour.
Prepare
acid and alkaline solution of different concentrations adding different
amounts of vinegar or soda or alkaline cleaners into water.
Measure pH of each solution with Hydrion Paper.
Add
equal amount of red cabbage pigment concentrate to the solutions and
check the color of the mixture. Can you read more color gradations in
the red cabbage indicator then in Hydrion paper indicator?
Approximately 10-12 billions of years ago first galaxies
were formed. The stars that were formed at that time called the 1st
generation stars. Some of them are still live, some of them become
white or
red dwarf stars. Many of them ended their lives as supernovas,
producing black holes or neutron stars and fertilizing our galaxy with
heavy elements of periodic table, providing matter for the Earth-like
planets.
Imagine that carbon, iron, calcium and other
heavy elements of our bodies originate from a star
that ended as a enormous blast visible from the distance of hundred
millions light years.
When our Solar System was forming most of
this heavy materials were absorbed by the planetoids orbiting the Sun.
Planetoids became the planets but some amount of this primordial matter
ejected from the old star still exists in form of the asteroids, comets
and small particles. In fact every day tons of this particles
collide with Earth and burn in it's thick atmosphere. Occasionally when
the piece is big enough - one inch or so - you can see a brief flash of
light crossing the night sky. A shooting star. It burns in the
atmosphere and almost never reaches the surface. However during
descent it disintegrates into smaller pieces. They brake in the
atmosphere and slowly fall down as a dust. They called micrometeorites. And
this is the star dust we're after.
Collecting this microscopic pieces of old supernova can be great 7th grade science fair project!
There are 2 main classes of micrometeorites - rock micrometeorites
and iron micrometeorites.
It's hard to isolate and distinguish rock micrometeorites
from other forms of dust and debris. Iron micrometeorites
are easier to collect because you can use magnet to concentrate them.
There are many ways to collect
micrometeorites. Basically the bigger area you can collect
dust from the higher chances of finding
micrometeorites.
Time and weather may be important too. Chances of finding
micrometeorites in the few days following meteor shower higher than
after few days of heavy rain when all the particles washed out of
atmosphere by water drops.
It's hard to collect micrometeorites
if you have persistent strong winds in your area. If you have snowfall
in your area it's a perfect chance to find good deal of micrometeorites
- snowflakes are frequently form around atmospheric particles and there
are chances that some of the particles will be the micrometeorites.
Snow is easy to collect and you can collect a lot of fresh and clean
snow from big area providing ideal conditions for micrometeorite search.
The goal of the project:
To find, isolate and identify micrometeorites.
To do this science project you'll need:
A large sheet of paper or thin plastic
(1-2 square meters)
Very strong magnet.
Strong lens or a binocular or a
microscope. Having all 3 instruments is the ideal conditions for the
experiment.
Procedure:
When weather forecast is good, unfold the
sheet of paper(plastic) outside in the open space and leave over night.
Collect it in the early morning when
atmosphere is still and there is no wind.
Make sure you collect it the way so that
all the material deposited on the sheet can only fall to the center of
the sheet.
Wrap strong magnet in the thin plastic
bag.
"Scan" sheet with the magnet collecting
all magnetic particles.
Place
magnet over the small container and gently remove magnet from the
plastic bag so that all the magnetic particles fall in the container.
Examine them with magnifying glass or
microscope.
You
may need to repeat this experiment several times to get enough
experience and increase chances of micrometeorite finding.
As
extension of this project you may try to calculate the weight of the
micrometeorites falling each year on the surface of the earth.
If you didn't manage to catch any micrometeorites using this method you
can try another one.
