Mold
can be excellent subject for the 5th grade science fair project. There
are different kinds of mold and we are dealing with them daily. Some of
them are useful (think of Camembert cheese or antibiotics), some of
them can be harmful causing allergy and diseases. So, yes, studying
mold is important.
It's also generally very easy organisms to work with so setting up an experiment is simple and does not take a lot of time.
Check our example of the bread mold garden and suggestion for other mold experiments.
Another 5th grade microbiology project that does not require microscopy is experiment with yeasts.
Yeasts (Saccharomyces cerevisiae)
generally indicate that they are alive and happy by producing a lot of
gas. Carbon dioxide that is. It's a by-product of yeasts aerobic metabolism. People use it for dough making. In tough anaerobic (lack of oxygen) conditions yeasts produce less gas and more alcohol and vinegar. Which is also useful.
Yeasts
use sugar as their primary source of energy, but pure sugar is
rare in the nature, usually it stored in some kind of biopolymer like
starch. So the goal of this microbiology experiment is to find how good
yeasts are at utilizing different kinds of sugars and sweeteners.
Basically answer the question, what substrates yeasts can live on and feel well? We can
measure their well-being by measuring the amount of gas they produce.
You'll need
Sugar, maple syrup, corn syrup, maple sugar, starch, whatever-you-want - these are substrates you'll be testing.
Bottles of the same size. One bottle for each substrate and one bottle for control. Small fizzy drinks bottles work fine.
Yeasts.
Toy balloons - one balloon for each bottle. All balloons should be the same size.
Marker
Sticky tape or thread.
Procedure:
Dissolve one tablespoon of the substrate
in one glass of warm water. Add one teaspoon of yeasts. Pour
mixture in the bottle. Write substrate name on the bottle with
marker. Repeat procedure with next substrate. When all bottles
filled prepare control bottle - add yeasts to fresh water with no
substrate and fill control bottle with this mixture.
Put a balloon
over each bottle. Make sure that balloons are sitting airtight. Securing
them with sticky tape or thread around the bottle neck is a good idea.
Put
bottles in the reasonably warm place. Check them every half hour.
You will notice that some of the balloons are getting filled with gas.
Some of them will grow faster then the others. Don't forget to write down your results and build a graph.
Depending
on what you need there are many ways to clean the water. The simplest
way is filtration with some kind of porous material (cloth or cotton in
the very simple case). This kind of purification provide basic
purification filtering out dust, dirt, sand and other macroscopic
particles you may find in the water. It will also filter out small
round worms and perhaps large single cell organisms. You would be
surprised to see how many of them can be in single drop of some pond
water!
However this kind of purification would not clean water from bacteria, viruses and dissolved minerals.
In this 5th grade science project we will study which purification method can better purify salted water.
At home you can use 2 methods to do that - distillation and crystallization.
You'll need
Water.
Salt and/or soda.
Large pan.
Plastic wrap.
Glass and small bowl.
Freezer.
Plastic bowl.
You'll need to create water distiller and water crystallizor.
Here you'll find pretty cool video that explains in details how to make a simple sun powered water distiller.
For
crystallizer you'll just use a plastic bowl. Fill it with salty water and
put it in the freezer. Check it from time to time. When you see that ice
filled half of the bowl in the bowl, collect it and put in the clean
glass. Don't wait until all the water in the bowl get frozen.
When
enough water is distilled and crystallized, compare the results. You
can taste the water, you can also put equal amount of water on the
clean surfaces (plates, glass, polished table will work even though
using polished table for experiments is not a good idea). Wait
until water dries. All salts remaining in the water will stay on the
surface and you can judge which water sample was cleaner.
Does field and forest have different soil composition?
Soil composition can provide important information about
agricultural potential of location, what kind of plants can grow on the
soil, etc.
At home you can study soil profile, amount of water in different soils, soil salinity and pH, organisms that live in the soil.
To study soil profile you'll need
Soil
samples from 2 or more locations. If you want to study natural soil
composition make sure that location is unaffected by gardening or other
development.
You'll also need glass jars with lids to collect your samples.
Find
good location clear from large plants. Remove few inches from the surface of the
soil and fill half of the jar with the soil from the depth of 5-6
inches. Tag your sample (write location name or number on the jar with
permanent marker)
At home fill the jar with water, cover and shake it until all big clamps of soil breakup in the water. Do not shake too hard as pebbles in the soil can break the glass.
Set
the jar in safe place for a few days (week is a good time). During this
time all soil components will settle. First the most heavy and hard
components as rocks and pebbles will set, then sand, silt, clay and
finally organic remains. When it all settled you can measure
relative thickness of the layer, and compare soil composition form the
different places.
What other things you can try?
Measure
relative wetness of soil. Compare composition of the soil from the
different depths. For example compare the composition of the surface
layer, the sample of the 10 inches depth and the sample of the 3
ft depth.
Does soil contain salts? You can put 10g of
soil in 10g of water, shake it well, wait till soil settles, then
filter the water and dry it. The remaining spot will contain minerals
from the soil sample. At home you won't be able to accurately measure
the quantity of the minerals, but you can try to judge visually which
soil contains larger amount of salts.
You can also measure soil pH using red cabbage indicator or indicator paper you can buy in the garden shops.
