1. Bias, Correlation, Causation, Hypothesis, Law, & Theory

2. Main Topics Take at least one note for each of these topics: Bias
Correlation
Causation
Hypothesis
Law
Theory
Remember, you decide what is important to write down.

3. Be Objective
Bias-when what the scientist expects changes how the results are viewed
May cause a scientist to prefer results of one trial over another.
If the advantages of a product being tested are used in a promotion and the drawbacks are not presented

4. How to Reduce Bias Run as many trials as possible.
Keep accurate notes of each observation made.
Use data that is measurable.
The experiment must be repeatable.
Findings are supportable when other scientists perform the same experiment and get the same results.

5. Definition of Causation
When a specific action causes a second event to happen
Cause and effect

6. Definition of Correlation
when two or more things or events tend to occur at the same time and might be associated with each other, but aren’t necessarily connected by a cause/effect relationship

7. Researchers don’t jump to conclusions.

8. Well, sometimes we do…but we try not to.
Example:
Ulcers.

9. Causation?
We used to believe that ulcers were caused by stress and spicy food.

10. Causation
There was a correlation between the independent variables (stress/spicy food), and the dependent variable (ulcers) but the independent variables were NOT the cause.
We now know that ulcers are caused by a corkscrew-shaped bacterium Helicobacter pylori (H. pylori).

11. Correlation
Natural stomach acids and spicy food may have irritated the already damaged stomach and small intestine, but they never caused the ulcers.
For more information on ulcers, see

12. Causation
Correlation studies help us determine the existence of a relationship between variables.
This relationship can help us design more precise, experimental studies to better understand our environment and causation.

13. Hypothesis, Laws, Theories
Thanks to T Landry

14. Hypothesis:
This is a specific prediction based upon observation. It is a rational explanation of a single event or phenomenon based upon what is observed, but which has not been proved.
Most hypotheses can be supported or refuted by experimentation or continued observation.

15. Scientific Law
This is a statement of fact meant to describe an action or set of actions.
It is generally accepted to be true and universal
Sometimes can be stated as a single mathematical equation.
Scientific laws must be simple, true, universal, and absolute.

16. Examples of Laws Law of gravity Newton's laws of motion
the law of conservation of mass and energy,
Hook’s law of elasticity.

17. Examples of Laws Law of gravity Newton's laws of motion
the law of conservation of mass and energy,
Hook’s law of elasticity.
Hooke's law accurately models the physical properties of common mechanical springs for small changes in length

18. Laws Come With Specific Conditions
Newton's law of universal gravitation only applies in weak gravitational fields

19. Theories
Theories are constructed to explain, predict, and master phenomena.

20. Theories in Science A scientific theory must:
be testable or lead to predictions that are testable
involve reproducible results

21. Laws vs theories
A law describes a single action, whereas a theory explains an entire group of related phenomena.
A law differs from a scientific theory in that it does not explain; it is the results of repeated observation.

22. Right or Wrong?
Theories are abstract and conceptual, and to this end they are never considered finally proven.
Instead, they are supported or challenged by observations in the world.

23. Falsified, Revised, Shelved
Sometimes theories are falsified and discarded, because new observations don’t match the theory.
More often, theories are revised or tweak to include and conform to new observations.

24. Examples of Scientific Theories
Astronomy: Big Bang Theory
Biology: Cell theory — Evolution — Germ theory
Chemistry: Atomic theory — Kinetic theory of gases
Climatology: Theory of Global Climate Change (due to human activity)
Geology: Plate tectonics
Physics: Theory of relativity

25. Biology Miasma theory of disease
A representation of the cholera epidemic of the nineteenth century depicts the spread of the disease in the form of poisonous air.
Replaced by the Germ Theory of Disease

26. Geology Continental drift was superseded by plate tectonics
Plate tectonics, a modern update of the old ideas of Wegener about "plowing" continents, accommodates continental motion through the mechanism of seafloor spreading.

27. Progression of atomic theory
A schematic representation of the
Plum pudding model of the atom.

28. Progression of atomic theory
Rutherford Model

29. Progression of atomic theory
Rutherford Bohr Model

30. Progression of atomic theory