Microorganisms

MicroorganismsWhere do microbes live?

Where do microorganisms live?

Where in the classroom do you think we would find the most microorganisms?

Gather Round

How can we grow microorganisms?Microbiologists grow bacteria and fungi on agar

plates.

Agar is special jelly; it contains all the nutrients bacteria and fungi need to grow.

Molten agar is poured in Petri dishes.

Step 1

bottom with agar

lid

bottom with agar

lid

Turn your Petri dish upside down

Step 2

On the bottom of your Petri dish write your initials and the date

bottom

Step 3

Mark the bottom of your Petri dish into quarters

bottom

Step 4

In each quarter write what you are swabbing

bottom

Step 5

bottom with agar

lidbottom with agar

lidFlip over your Petri dish so the lid is back on top

Dip one of your cotton buds in water and rub what you want to test

Step 6

Take the lid off your Petri dishWiggle your cotton bud on the agar GENTLY

Remember to put it in the

right quarter

Step 7

Put the lid back on your Petri dish between each test

Put the used cotton bud in Vircon and use a new one for the next test

Step 8

When you have tested 4 objects seal your dish with 4 pieces of sellotape

Tips Write around the edge of the Petri dish

The dustiest objects don’t necessarily have the most microbes

Only seal the Petri dish at 4 points

When you’re finished wash your hands

Complete record sheetInclude:

- your name- what you swabbed

Remember to write around

the edge

Predictions

What do you think the dirtiest object in the classroom is going to be?

What do you think the agar plates will look like on Thursday?

Microorganism Reproduction

The number of microorganisms doubles every 20 minutes…

…if you start with 1 microbe how many will there be after 4 hours?

0 minutes = 1 Bob

20 minutes = 2 Bobs

40 minutes = 4 Bobs

60 minutes = 8 Bobs

80 minutes = 16 Bobs

100 minutes = 32 Bobs

120 minutes = 64 Bobs

140 minutes = 128 Bobs

160 minutes = 256 Bobs

180 minutes = 512 Bobs

200 minutes = 1024 Bobs

220 minutes = 2048

240 minutes = 4096

260 minutes = 8192

280 minutes = 16,384

Microbe Multiplication Song!

http://www.youtube.com/watch?v=5Xi2Nc1UicQ

Where do microbes live?

Is it round and smooth?

Is it hairy or fuzzy?

What colour is it? What size is it?

You have found bacteria

You have found fungi

Different colours and size mean different types of bacteria/fungi.

DO NOT open your Petri dishes

Where do microbes live?

1. Write the title “where do microbes live?” in your jotter2. Stick the records of your swabbing in your jotter3. Draw your results on your record sheet4. Copy the table below (use a ruler)

Object Scale of microbial growth

03

2 1

How much growth?Complete your results table using the diagram

below to help you decide how much growth is on your plate.

Nothing is growing

A couple areas of growthMostly covered in growth

Completely covered in growth

What is the dirtiest object in the classroom?Object Scale of microbial growth Average growth

Next day...

What do microorganisms need to live?