1. Emerging Diseases Lecture 2: The Scientific Method 2.1: Overview
2.3: Scientific Theories

2. 2.1: Overview-Science as a Process
“Scientific Method”
Common sense way of asking questions and getting answers about nature
Organized and logical but also intuitive and personal
Science is a part of human society and culture
Science is a social activity-all scientists are people!

3. 2.2: The Scientific Method:
It starts with information or observations.
The information generates a question.
The question suggests a possible answer or answers.
The possible answer is called a hypothesis.

4. Scientific Method The hypothesis has to be checked out or “tested”.
In the natural sciences (biology, chemistry, physics) the test is often made via an experiment.
An experiment is a test of a hypothesis carried out under controlled conditions.

5. Scientific Method
The results of the experiment either support the hypothesis or do not support the hypothesis.
It just depends on how the results turn out
Of course scientists usually prefer it when the results support the hypothesis.
But either way, the results lead to new questions and experiments.

6. The Scientific Method is Cyclical
Questions generate results: results generate questions.

7. Scientific Knowledge is Powerful
Because it is based on real-world experiments
And it can always be re-tested and re-checked
But Scientific Knowledge is Tentative
Because there are always more questions
Scientific knowledge can be falsified, modified, shown to be limited or even discarded depending on the results of new experiments.

8. 2.3: The Scientific Method Builds up to Theories
A really important hypothesis that has been tested and supported many times is called a theory (sometimes called a law).
A theory has stood up to all tests for so long that the scientific community does not really question it any longer-a consensus is reached.
Even so, someday, somewhere some other scientist might show that the theory is not always correct.

10. A scientific theory is different from a theory in the media!!!!!!!!!!

11. A scientific theory is backed up by a large body of hard evidence
A scientific theory is backed up by a large body of hard evidence. A scientific theory is generally accepted by the community. News anchors, talking heads, radio and TV personalities can make up anything they want and call it a “theory”. They don’t need evidence, discussion or consensus!

12. The End of a Theory
Eventually a theory gets old and becomes less useful.
New evidence accumulates and the old theory has a hard time explaining it.
Time for a new theory or a modified theory.
The switchover is called a paradigm shift.
An example is the shift from humoral medicine to the Germ Theory.