Understanding Scientific Method: Hypothesis, Experiment Design, and Data Analysis, Study notes of Design

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THE SCIENTIFIC

METHOD IN

ACTION

SCIENCE

If you don’t make mistakes, you’re doing it wrong If you don’t correct those mistakes, you’re doing it really wrong If you can’t admit that you’re mistaken – then you’re not doing it at all!

Where do we get

knowledge?

◦Acceptance of “truth”

◦ From inherited customs, traditions

◦ Authority figure

◦Trial and error ◦Deductive reasoning

◦ Assumptions from existing knowledge

◦ Uses logical arguments (If… then)

The Scientific Method according to Monty Python ( enjoy )

Scientific Method

◦ Scientific method

◦ Most reliable way of obtaining information ◦ You can test what you believe to be true ◦ Others can repeat your experiment ◦ Opportunity to prove false ◦ Follows general set of systematic procedures ◦ Self validating system that establishes fact from belief

Ethics

◦ What makes an experiment ethical? ◦ Is photosynthesis experiment unethical? ◦ Is an unethical experiment worth completing? ◦ Example: Pavlovs Dogs ◦ Was this an ethical experiment? Why or why not?

Problem/Question John watches his grandmother bake bread. He ask his grandmother what makes the bread rise. She explains that yeast releases a gas as it feeds on sugar.

Caution!

Be careful how you use effect and affect.

Effect is usually a noun and affect, a verb.

“ The effect of sugar amounts on the rising

of bread.”

“How does sugar affect the rising of

bread?”

Formulate a Hypothesis ◦ After conducting further research, he comes up with a hypothesis. ◦ “If more sugar is added, then the bread will rise higher.”

How many variables do you test at one time?

Ockham's Razor ◦ It states that among competing hypotheses, the one with the fewest assumptions should be selected. When you hear hoof beats think horses, not zebras

(d) Formulate a hypothesis on the basis of experimental data. ◦ With reference to experimental data, candidates should be able to state an operational hypothesis. For example, a table of data might suggest that, as the concentration of nitrate ions increases, the growth of algae also increases. From the data, candidates could suggest the hypothesis that ‘there is a positive relationship between the concentration of nitrate ions and the growth of algae’. One test is worth a thousand expert opinions. ◦ Bill Nye

Independent Variable

The independent, or

manipulated variable, is a

factor that’s intentionally

varied by the experimenter.

John is going to use 25g., 50g., 100g., 250g., 500g. of sugar in his experiment.

Dependent Variable

The dependent, or

responding variable, is the

factor that may change as a

result of changes made in

the independent variable.

In this case, it would be the size of the loaf of bread.