Grade 6 – LAB 4: Microorganisms 2

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

Use the structure below to write your hypothesis:

If (the surface is…)
then (I think I will see more/less of certain microorganisms),
because (give a scientific reason why).

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.

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:

  1. Put on gloves. Label each ziplock bag with the name of the surface to be tested.
  2. Rub a bread slice directly on the selected surface.
  3. Place the bread slice into its labeled ziplock bag and seal it.
  4. Store the bags in a warm, dark place for 3–7 days.
  5. Do not open the bags. Observe and record results daily.

Results:

Day 1:

Day 2:

Day 3:


Data Collection Table:

SampleSurface TouchedDay Mold First AppearedMold Color(s)Mold Area (S/M/L)Notes (spots, etc.)
1
2
3
4

Discussion:

Answer the following questions (full answers)

  1. Which sample showed mold growth the fastest? Why?
  1. Which surface caused the most microbial growth? Explain your reasoning.
  1. How do your results compare between clean and dirty surfaces?
  1. What environmental factors might have affected mold growth?

Conclusion:

  1. Was your hypothesis correct? Why or why not?
  1. What did you learn about micro-organisms from this experiment?
  1. What could you change or test next time?
  1. How does this experiment relate to your daily life?

ATTENTION: Never open the ziplock bags. Dispose of the samples properly after the experiment.