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1. HSC Biology
• Module 3: The Search For Better Health
1. Over 3000 years ago
the Chinese and
Hebrews were
advocating cleanliness
in food, water and
personal hygiene
1. • Identify data sources, plan and choose
equipment or resources to perform a first-hand
investigation to identify microbes in food or in
water
2.
Students:

2. What happens when microbes
and other unsavoury things get
into our food and water

3. Equipment:
1. 5 Agar Plates
2. An array of food
3. Water samples
4. 5 Swabs
5. Tape
6. A catalogue
Aim: Identify microbes in food or water

4. Method:
1. Swab the different types of foods and
water available
2. Use the swab to transfer microscopic
microbes from the sample and onto the
agar in the petri dish
3. Seal each petri dish and leave them in the
same external conditions
• Factors like light, temperature and
humidity can have a direct effect on
the growth of the microbe

5. Method:
4. Leave the petri dishes for 5-7 days
5. Observe the results and record the growth
of microbes in each dish
6. Use a catalogue to identify and name the
growth of microbes you see

6. Results:
Bread Tap Water Crackers and Jelly

7. Results:

8. Results:
If fungi is present in food.

9. Results:
If fungi is present in food.
One colony

10. Results:
If fungi is present in food.
One colony
Many colonies

11. Results:

12. Results:
Many colonies

13. Results:
Many colonies
One colony equates to
several million bacteria
Some microbes will grow quickly whilst
others will grow slowly. The speed at
which bacteria grows at depends on
their metabolism. Some bacteria have
fast metabolism while others don’t

14. Results:
Deduce a number of things about them:
• Colours Produced
• Types of Bacteria Present

15. Results:
1. Which petri dish produced the most
diverse forms of micro-organisms?
2. Which petri dish produced the
largest/smallest number of
colonies?
3. Is it just bacteria that you can see
or is there fungi as well?

16. HSC Biology
• Module 3: The Search For Better HealthSafety Considerations
Make sure the petri dishes are sealed and not opened until they’re
meant to be.
• This is important since there’s a chance that harmful bacteria could be
produced and you wouldn’t want to get in contact with any of that.
1

17. HSC Biology
• Module 3: The Search For Better HealthSafety Considerations
Make sure the petri dishes are sealed and not opened until they’re
meant to be.
• This is important since there’s a chance that harmful bacteria could be
produced and you wouldn’t want to get in contact with any of that.
1
Ensure that gloves are worn and always wash your hands with soap.2
• Wearing gloves reduces the chance of having
microbes come into contact with your skin whilst
washing your hands with soap will kill any
microbes that might have snuck on-board.

18. HSC Biology
• Module 3: The Search For Better HealthSafety Considerations
Be careful when working with
microorganisms, and always
safely dispose of the waste
once finished.
• There’s a higher risk of infecting
yourself and others with these
microbes.
3
• Always be careful and always
dispose of these microbes
safety.