Scientific Methodology

• a way of knowing about the world.

• a process using observation and data to investigate and understand our universe.

SCIENCE IS…

Scientific Methodology

• based on observation and interpretation of physical evidence

• subject to strict, repeated testing and peer review

Observation

vs. Inference

• use one or more of your senses

• Good observations are accurate (exact) and objective (unbiased)

• Observations are either qualitative (no #’s) or quantitative (uses #’s)

Observations

Tell if the following are accurate and objective

• 16 students were on-time to class, and five students were tardy

• Half the class was late

• The funniest people showed up first

accurate & objective not accurate

not objective

Observation

Tell if the following are qualitative or quantitative:

• The door is blue

• There are three doors in the room

• The floor tiles are shiny

• The floor tiles are 12”x12”

qualitativequantitative

qualitative

quantitative

Observation

• when you explain or interpret an observation

• should be reasonable (makes sense)

• some inferences are unreasonable (far-fetched)

Inference

EXAMPLES

• I see football players wearing uniforms,

• they must have a game today.

• they must like string cheese.

observation

inference, reasonable

inference, unreasonab

le

Inference

The plant is in a pot

inference

The plant has roots

The plant uses water

The plant has leaves

The plant is green

The plant is growing in

soil

observation

Observation or Inference?

Self Check

• What two qualities make an observation scientific?

•Write two scientific observations about the classroom.

• How is an inference different from an observation?

Observations lead to

Questions A scientific Question or Problem arises from

our observations. Observation: My dog is shedding more than

usual. What kinds of questions

might you ask after this

observation?

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A hypothesis is an educated guess as to what you think the answer to your question might be.

Good hypotheses are reasonable and evidence based.

Hypothesis

• Determine a Procedure to test whether hypothesis is correct.

•The outcome must be measureable (quantifiable).

Experiment

• Perform the experiment to see if the experiment yields the predicted results.

• If the expected results are obtained, the hypothesis is supported (but not proven).

Don’t forget toRECORD YOUR DATA

Experiment

When testing, it is important to perform a controlled experiment.

Good experiments usually have an “experimental group” and a “control group”.

The two groups are treated EXACTLY alike except for the ONE variable being tested.

Controlled Experiment!

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The control group is the baseline, or standard, against which you measure the effect of the introduced variable.The experimental group is the group into which you introduce one varying factor (variable). + +

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Control Group!

… while the experimental group is given a pill that is intended to improve their memory.

For example, in an experiment to test the effects of a memory-enhancing drug, there would be a control group, consisting of normal, everyday people…

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Control Group!

Nearly all experiments have variables – or factors that can affect an experiment.

There are three types:• independent (manipulated)• dependent (responding)•controlled variables

Variables!

Independent (manipulated) variable• the thing that someone actively changes,•What you are testing• the “cause”

Dependent (responding) variable• the thing that changes as a result of the independent variable•The thing you measure• the “effect”

Variables!

EXAMPLEIn our memory-enhancing drug experiment…

• independent variable = (what we test)

• dependent variable =(what we measure)

Variables!

pill given to members of the experimental group

memory of members in the experimental group

• control variable = any factors that could have an affect on your experiment.

•In the memory experiment, what factors do you need to control, so we know the ONLY thing changing memory is the pill?

Variables!

Examine the data from your experiment, looking for trends, patterns, or any other evidence that can lead to a reasonable conclusion

ANALYSIS

Analysis!

Data must be measurable and accurate!

ANALYSIS

Giving a test before and after, and comparing scores

Asking the participants if they think their memory is better

Not accurate, subjective

Accurate, objective

Analysis!

In the case of our memory-drug experiment:

We would look at our data and try to determine if the memory of the people in our experimental group was any better (or worse) than the memory of those in our control group

ANALYSIS

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Analysis!

• Restate your hypothesis• State whether your prediction was

confirmed • Explain your results.

Conclusion/Results!

When writing a conclusion for labs:•Include discussion of errors •Include Future Research ideas