Download the discovery of penicillin

THE DISCOVERY
OF PENICILLIN
The scientific method
Step 1: Fleming made an
observation
Observe what is around you and start
thinking why processes happen.
In 1928,
Alexander Fleming
was studying bacteria
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and he observed by chance...
(Observation)
he observed a blue-green fungus
(mould) growing on a dish of bacteria.
and he observed also that some
bacteria were killed.
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Petri dish
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Step 2: Fleming formulated
a Hypothesis
Femming´s
hypothesis:
“Mould kills bacteria”
a
Hypothesis is an idea that
explains a phenomenon
Step 3: Fleming tested
the hypothesis
Fleming searched for more information:
He found:
– The Greeks and the Chinese (more than 1000
years ago) used moulds to treat infection
– In 1877 Pasteur had observed similar results
(Fleming tested the hypothesis)
and then, Feming performed these
experiments and these are the results:
bacteria with fungus:
Result: bacteria was killed
bacteria without fungus
Result: bacteria lived
(Testing the hypothesis)
We perform experiments to test hypothesis!
First, you do some research about your
subject
Second, you plan the experiment
During the test:
– you collect data (numbers like
temperature)
– you write down observations.
Keep all data (including wrong ones).
Step 4: Fleming drew
conclusions
Fleming arrived at the following
conclusion:
Mould kills bacteria
He concluded that the mould produced
a substance that killed the bacteria.
After several investigations he
discovered the substance and he called
it penicillin
(Drawing conclusions)
You
explain the meaning of your
results.
DOES THE
EXPERIMENT
FITS THE
HYPOTHESIS?
YES
NO
THE
HYPOTHESIS
WORKS!
BACK
TO
STEP
2
WE SHOULD
FORMULATE
ANOTHER
HYPOTHESIS
The discovery: Penicillin
Nowadays Penicillin is a common antibiotic,
used to treat bacterial infections such as
meningitis, pneumonia or colds. Not flu!
Penicillin saves lots of lives
because it kills bacteria
that cause infections.
During World War II, penicillin
saved lives and avoided
amputations caused by infected
wounds
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THE SCIENTIFIC METHOD
STEP 1:
OBSERVATION
OF A
PHENOMENON
STEP 2:
FORMULATE
A
HYPOTHESIS
STEP 3:
TESTING THE
HYPOTHESIS
START AGAIN
STEP 4:
DRAWING
CONCLUSIONS
NO
THE
HYPOTHESIS
DOESN´T FIT
THE
OBSERVATION
YES
THE
HYPOTHESIS
FITS THE
OBSERVATION
MAYBE
YOU CAN
DO A NEW
THEORY!!