MECHANI
CS
• Divide theclass into 4 groups.
• Each group sends one
representative.
• Representatives answer survey-
style science questions.
• The group with the highest
points wins.
3.
Why do foodsspoil after
several days?
PROCESSING QUESTIONS
QUICK ANSWER
Foods spoil because microorganisms
grow in them.
4.
Why do hospitalsrequire
cleanliness and
sterilization?
PROCESSING QUESTIONS
QUICK ANSWER
Cleanliness prevents microorganisms from
spreading infection.
5.
How do vaccineshelp
prevent diseases?
PROCESSING QUESTIONS
QUICK ANSWER
Vaccines help the body develop protection
against diseases.
6.
Lesson
context
Key
concepts
Activity
Investigation
Explain how LouisPasteur’s discoveries helped scientists
understand microorganisms and disease prevention.
AT THE END OF THE LESSONS, LEARNERS WILL BE
ABLE TO:
Construct a simple timeline showing Louis Pasteur’s major
discoveries and their modern applications
Appreciate the importance of scientific discoveries in improving
human health and safety
Why do peopleget sick?
Many people believed that diseases appeared
spontaneously or were caused by bad air.
Scientists had limited understanding of
microorganisms and how infections spread.
Through careful observation and
experimentation, Louis Pasteur demonstrated
that tiny living organisms called microbes were
responsible for many diseases and food spoilage.
9.
• Chemistry helpedhim study fermentation
and chemical changes in substances.
• Biology helped him understand the role of
microorganisms in these processes.
• His experiments showed that microbes come
from existing microbes rather than appearing
spontaneously.
How Pasteur combined
chemistry and biology in his
investigations:
10.
Swan-neck flask
experiment:
• Nutrientbroth was boiled to kill microorganisms.
• The flask had a curved neck that allowed air to
enter but trapped dust and microbes.
• The broth remained free from contamination.
• When the flask was tilted and the broth contacted
trapped particles, microorganisms grew.
This experiment provided
evidence against
spontaneous generation and
supported Germ Theory.
13.
Germ Theory
Germ Theorytransformed medicine because it
helped doctors understand how diseases spread.
Applications today include:
• Handwashing practices
• Sterilization of medical equipment
• Use of disinfectants
• Infection prevention in hospitals
How would hospitals be
different if Germ Theory had
never been discovered?
QUICK QUESTION
14.
Pasteurization
Why is pasteurization
importantfor consumers?
QUICK QUESTION
Pasteurization involves heating liquids to a specific
temperature for a certain period to destroy harmful
microorganisms without greatly affecting taste or
quality.
Examples:
• Milk
• Fruit juices
• Dairy products
15.
Vaccination Research
How dovaccines help
protect people who cannot
receive vaccinations?
QUICK QUESTION
Pasteur developed vaccines for diseases such as
rabies and anthrax.
Vaccines:
• Train the immune system to recognize
pathogens.
• Reduce the spread of infectious diseases.
• Protect both individuals and communities.
16.
Fermentation Studies
Understanding
fermentation improved
foodproduction and
quality control.
REMEMBER
Pasteur discovered that microorganisms play an
important role in fermentation.
Examples include:
• Bread production
• Yogurt making
• Cheese production
• Vinegar production
17.
Continuing Impact of
ChemistryDiscoveries on
Society
Scientific discoveries do not stop after they are
made. Scientists continue to improve and
expand knowledge to solve new problems.
• Disease surveillance
• Vaccination campaigns
• Community sanitation
programs
PUBLIC HEALTH
• Development of antibiotics
• Diagnostic testing
• Infection prevention
measures
Medicine
• Quality control in food
industries
• Safe food processing
methods
• Preservation technologies
Food Safety
• Biotechnology
• Microbiology
• Pharmaceutical
development
Scientific Research
WHO IS LOUIS
PASTEUR?
•French chemist and
microbiologist
• Studied microorganisms
• Developed Germ Theory
• Introduced pasteurization
• Developed vaccines
20.
Germ Theory ofDisease
• Germ Theory states that microorganisms cause
diseases.
• Before Pasteur, people believed diseases came
from “bad air.”
• Pasteur used experiments to prove microorganisms
exist.
Louis Pasteur combined chemistry and biology by
studying chemical changes caused by microorganisms. His
experiments helped scientists understand food spoilage,
fermentation, and disease transmission.
Why is Pasteur’sGerm Theory
considered one of the most
important scientific discoveries
in history?
Answer!
It changed how people understood diseases and
led to modern medicine, sanitation, vaccines, and
safer food practices.
23.
How might people’slives today
be different if scientists never
discovered microorganisms?
Answer!
Diseases would spread more easily, hospitals
would be less safe, and many food products
would spoil faster.
24.
Activity: “Discovery toDaily Life
Timeline”
• Using the internet, learners will look for Pasteur’s
discovery
• Learners arrange the discoveries chronologically.
• Beside each discovery, learners write one modern
application.
26.
What discovery ofLouis
Pasteur do you think has
the greatest impact today?
PROCESSING QUESTIONS
Exit Ticket
Learners answerthe following on a half
sheet of paper:
1.One important discovery of Louis Pasteur
2.One modern application of his work
3.One question they still have about the
lesson
30.
ASSIGNMENT
• Research anotherscientist who
contributed to medicine or chemistry.
• Observe labels on milk or food products
and identify products that undergo
pasteurization.