SCIENTIFIC METHOD REVIEW

Tuesday, August 4th, 2015

Textbook pages 15-19

“STEPS” TO THE SCIENTIFIC METHOD1.Make an

observation… ask a question

2.Do background research

3.Construct a hypothesis

4.Experiment5.Analyze Data6.Conclude &

Communicate

Observe and

Predict

Form testable

hypothesis/ prediction

Collect data/conduc

t experiment

to test prediction

Interpret results

Disseminate findings

WHY IS IT IMPORTANT TO BE OBJECTIVE AND METHODICAL?

OBJECTIVENo personal bias / investmentMust be reproducible by other scientists ** Not the same thing as consensus **

METHODICALOther researchers can understand how the data was collected

Other researchers can reproduce (replicate) the experiment

HYPOTHESIS

Must be testableIdea, proposition (suggestion), possible mechanism, statement about effect

NULL HYPOTHESIS

Sometimes it’s easier to prove something wrong than rightStatement/idea that can be proved wrong (falsified)

ACCURACY, PRECISION & UNCERTAINTY

Accuracy (how close) Precision (how repeatable)

Uncertainty: estimate of how much the measured/calculated value differs from the true value

SAMPLE SIZE & REPLICATION ARE IMPORTANT!Need to collect several sets of measurementsSample size = the number of times the measurement is repeated

INDUCTIVE VS. DEDUCTIVE REASONINGInductive: making statements from facts/examples

Miss Scott is wearing a black dress today. Miss Scott only owns black dresses.

Deductive: applying a statement to a fact/exampleMiss Scott only owns black dresses. Miss Scott is

a wearing a dress today. The dress must be black.

THEORY VS. NATURAL LAW

Theory: Repeatedly tested and has reached wide acceptance

Natural Law: A theory with no known exceptions (has been significantly tested)

EXAMPLE PASSAGE 1

An experiment is set up to determine if wheat grows better when it is planted by itself or together with clover. The setup involves 3 pans of each treatment. Set-up A, B, and C contain wheat alone. Set-ups D, E, and F contain clover and wheat planted together; in rows alternating one seed of each type. One hundred seeds are planted in each pan. All treatments contain the same type of soil, are planted in the same size of pan, are exposed to the same amount of sunlight, and are maintained at the same temperature throughout the course of the experiment.

1. The treatments planted with wheat alone are the

[A] Constant [B] Controls [C] Independent variable

[D] Dependent variable [E] Replication

2. The following statement provides a hypothesis for this experiment:[A] Wheat grows taller when planted by itself than when it is alternated with clover.[B] Clover grows better when planted by itself.[C] Wheat grows better when planted together with clover.[D] Clover grows better when planted together with wheat.[E] Both A and C are legitimate hypotheses for this experiment.

3. Several setups of each treatment are prepared to fulfill a very important requirement of scientific experimentation, specifically the need for

[A] Replication [B] Constants [C] A control

[D] An independent variable [E] A dependent variable

4. Constants (controlled variables) in this experiment are

[A] the pan of wheat, temperature, soil type

[B] temperature, number of seeds in each pan, sunlight.

[C] number of seeds in each pan, sunlight, one pan of wheat and clover.

[D] The pans of wheat alternated with clover.

[E] The same as the independent variable.