These types of fungi colony counting experiments are helpful for Science Fair Projects for 8th Grade.
|Image by Sornram Srithong from Pixabay
Material required for colony counting of bread molds (Rhizopus stolonifer) experiment:
The following materials are required to types of fungi colony counting experiment for Science Fair Projects for 8th Grade.
- Homemade Bread —— One packet
- Branded Bread ——- One packet
- Self-sealing cover ——– 12 nos
- Distilled water ——– 1 L
- Spray bottle ——– One
- sodium chloride (NaCl) ——– 100 gm
- Gloves ——– 12 pairs
- Mask ——- 24 pairs
- Hand sanitizer ——– one bottle
- Hand lens ——– One
Homemade bread has no artificial preservatives. But most of the branded bread contains permitted preservatives. Instead of distilled water, you can use purifier water.
|Bread Colony Counting Experiment
Standard Operating Protocol for bread mold experiment (Rhizopus stolonifer) experiment:
How to grow bread molds on the bread? It can take place naturally without any external agent. But for the experiment, we need an external agent and control to compare with our experimentation. First, we are going to discuss the control experiment for bread molds growth. Then we will see the colony counting calculation methodology for this experiment. Finally, we can do experimentation with sodium chloride (NaCl).
- Take a slice of the bread (8 cm X 8 cm) and spray the water mist both sides of it.
- Then put the bread in the self-sealing cover and blow some air like a pillow.
- Obser this cover of bread for the next few days.
- After a few days, you see the formation of mold colonies.
- A spore of fungi that landed on the bread creates each colony.
- Don’t open the bag (some people or even you are allergic to the mold)
Bioscience experiments are different from other branches of natural sciences (both physics and chemistry). The main task is to collect the quantitative data and that can be measurable. This measurement could be repeated in any part of the world. Now to collect the quantitative data in this types of fungi colony growth experiment is to observe how many days it takes for the first colony to appear in the bread.
How to count the colonies of the bread mold Experiment (Rhizopus stolonifer)?
We can count the total number of colonies on the bread surface. In the early stage, the types of fungi counting of the colony is easy. If it spread throughout the bread, it is difficult to count the colonies. Finally, we won’t able to observe any difference in colonies. Rhizopus stolonifer is a fast-growing fungus that could cover the entire bread in a few days.
During the course of the investigation, we can calculate the percentage of the spread of colonies on the bread. The main task is to find the duration of the faster growth of colonies. This is the best biology experiment for science fair projects for 8th grade. This could be done with the diagram drawing and statistical counting as in the following ways.
|Bread Colony Counting Calculation with 1cm x 1cm cell
More time, you check the formation of the colony in the bread after starting the experimentation. The sides of the bread are not included in our calculation method.
Draw the bread on the paper:
Making square cells on the paper:
The bread size is 8cm X 8cm. So we can make 64 square cells of 1cm X 1cm dimension on one side of the bread. we are not calculating the plastic touching part of the bread. The bread part on the air used for the entire calculation. You should mark that part of the bread for the entire calculation.
Square cell calculation for mold growth:
The full growth of the mold in the 1cm X 1cm square cell is considered as 1. If it spread half part of the 1cm X 1cm square cell, then we can use 1/2. If it spread less than half part of the 1cm X 1cm square cell, then we can use 1/4. If it spread more than half part of 1cm X 1cm square cell, then we can use 3/4.
We can write these fractions from the hand-drawn diagram. After that, we add them up as mold growth. Finally, we add a full square cell 1cm X 1cm. This will give the total number of squares with mold.
% of Mold growth = [(fraction of mold grown cells+whole moldy cell] X100
Total number of cells in the bread
In our case, the Total number of cells in the bread is 64
Experimentation with different bread:
We can use different types of bread for these studies. We could compare the mold growth rate between homemade and branded bread. But you should remember that the preservative used in the branded bread. You note down the information of preservative in the bread.
Experimentation with saltwater on bread:
We can see the salt water effect on the bread sample. You just repeat the above-said experiment with the addition of salt water spray instead of normal water. You can take normal water spray bread as a control. You can compare salt water bread’ mold growth with normal water. Sodium chloride concentrations are 10ppm, 20ppm, 30ppm, 40ppm, …..and 100ppm.
What is parts per millions (ppm)?
Parts per millions (ppm) means x mg of sample in 1000ml or 1 L of solvent. One ppm is equivalent to one mg per liter of solvent. It can be represented mathematically as follows
1 ppm = 1 mg/L
This project results present as a poster for science fair projects for 8th grade.