Patterns, Cause/Effect & the Scientific Method

Was the Stonehenge birth of Astronomy ?

OR proof of Ancient Alien Astronauts?

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Occam’s razor – the simplest answer is the most likely the right

answer

SO…what is Science?

Scientific study normally begins with a problem ora testable subject/situation

Scientists try to answer the question WHY? And/or fix a problem

1) define the problem• write a testable question

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Cholera & Epidemiolog

y–intestinal disease caused by the bacteria vibrio cholerae resulting in severe diarrhea, vomiting, dehydration and death

–field of medicine that studies outbreaks of disease that affect large numbers of people

John Snow and John Snow and CholeraCholera

Hypothesize ??????????

2) research existing knowledge of the problem or situation helps a scientist form

3) hypothesis - an

educated guess;

testable explanation

A hypothesis must be able to be tested…

4) experiment – testing a hypothesis using a series of steps with controlled conditions

variable – something

that causes the

changes observed

in an exp.

Independent variable – quantity changed by the scientist (“If I do this…”)

Dependent variable – quantity that changes in response to independent variable

(it depends on independent

variable)

(“Then this…will happen”)

Experimental Design

In a well planned experiment, the independent variable should be the only condition that affects the experiments outcome

control – basis of comparison,

doesn’t change,

not exposed to experiment

Experimental Design

Observations give evidence…

Qualitative Observations made using senses

•Color•Odor•Texture•Shape

should use descriptive language so you can communicate to someone else what happened during the experiment

write down ALL things that happen that MAY impact what you are testing

Observations give evidenceQuantitative Observations are measurements

(sets of numbers that may support cause/effect relationships)

• Length• Volume• mass• Time• Temperature

ALL DATA MUST HAVE UNITS

Observation vs. InferenceObservation is a fact

Inference is a logical interpretation based on observation

5) Organize & Analyze Data

Helps show patterns that give cause and effect relationships between variables that

may support the hypothesis

The X axis is ALWAYS the independent and the Y axis is ALWAYS the dependent variable.This graph shows how your education level

(independent) effects your salary (dependent) as an adult!

6) Conclusion – a judgment based on the information obtained in experiment

((A conclusion can never be proven…((A conclusion can never be proven…data can support it BUT if further data can support it BUT if further evidence does not support it then evidence does not support it then the hypothesis is discarded or the hypothesis is discarded or modified))modified))

Theory – is a hypothesis that has been tested again and again by many scientists, with the same results each time, the best explanation science has to offer about a problem