Question:
Which everyday surfaces transfer the most fungi and bacteria to bread slices?
Hypothesis:
A hypothesis is a possible answer to your research question. It explains what you think will happen before you do the experiment. You can build your hypothesis using this sentence structure:
If (something changes — the independent variable), then (you expect this result — the dependent variable), because (reason or scientific explanation).
In Our Experiment:
- Independent variable = The surface (desk, phone, doorknob, etc.)
- Dependent variable = The amount or type of micro-organisms that grow
Example:
- If the surface is touched very often (like a phone or doorknob), then more fungi and bacteria will grow, because more people transfer germs to it.
- If the surface is usually cleaned (like a bathroom sink), then fewer colonies will grow, because disinfectants reduce micro-organisms.
- If the surface is in a humid area (like a sponge), then more fungi will grow, because fungi grow better in moist environments.
Objective:
Investigate how fungi and bacteria grow on bread slices after contact with different surfaces and understand the presence of micro-organisms in our environment.
Materials:
- 3–4 slices of plain white bread
- 3–4 ziplock bags (one per bread slice)
- Gloves
- Cotton swabs (optional)
- Marker or tape + pen (for labeling)
Procedures:
- Put on gloves. Label each ziplock bag with the name of the surface to be tested.
- Rub a bread slice directly on the selected surface OR rub the surface with a cotton swab and then apply it to the bread.
- Place the bread slice into its labeled ziplock bag and seal it.
- Store the bags in a warm, dark place for 3–7 days.
- Do not open the bags. Observe and record results daily.
Data Collection Table
| Sample | Surface Touched | Day Mold First Appeared | Mold Color(s) | Mold Area (S/M/L) | Notes (spots, etc.) |
|---|---|---|---|---|---|
| A | |||||
| B | |||||
| C | |||||
| D |
Discussion:
Answer the following questions (full answers)
- Which sample showed mold growth the fastest? Why?
- Which surface caused the most microbial growth? Explain your reasoning.
- How do your results compare between clean and dirty surfaces?
- What environmental factors might have affected mold growth?
Conclusion:
- Was your hypothesis correct? Why or why not?
- What did you learn about micro-organisms from this experiment?
- What could you change or test next time?
- How does this experiment relate to your daily life?
ATTENTION: Never open the ziplock bags. Dispose of the samples properly after the experiment.