The Scientific Method!

A step by step guide for the rest of the year.

The Scientific Method involves a series of steps that are used to

investigate a natural

occurrence.

Knowing and following

these steps are crucial to both this class and the TAKS

test!

Problem/Question

Observation/Research

Formulate a Hypothesis

Experiment

Collect and Analyze Results

Conclusion

Communicate the Results

Steps of the Scientific Method

1. Identify a Problem/QuestionProblem/Question: Must be

testable!!!!!!

2. Make Make observations and observations and

conduct researchconduct research: has anyone else looked at this problem?

Steps of the Scientific Method

3. Formulate a Formulate a HypothesisHypothesis: Predict a possible answer to the problem or question.

4. ExperimentExperiment: Develop and follow

a procedure.

Include a detailed materials list.

The outcome must be measurable (quantifiable).

Steps of the Scientific Method

5. Collect and Collect and Analyze ResultsAnalyze Results:

Modify the procedure if

needed.

Confirm the results by retesting.

6. ConclusionConclusion: Include a statement

that accepts or rejects the hypothesis.

Make recommendations for further study and

possible improvements to the

procedure.

Steps of the Scientific Method

7. Communicate the Communicate the ResultsResults: Be prepared to

present the project to an audience.

Expect questions from the audience.

The example

Lets take a basic problem and analyze it scientifically.

Problem/Question

Belton lake fish are dying in large numbers. Coincidentally a new Industrial plant has opened and has been discharging waste into the lake.

Observation/ResearchWe would research

the type of waste being discharged from the factory. Have any similar

cases been reported in the

past, etc, etc….

Formulate a Hypothesis

Textbook definition: The hypothesis is an educated guess about the

relationship between the independent and dependent

variables.

Formulate a Hypothesis

This can be tricky! Your hypothesis

must be simple, direct, and testable.

=

We will often use an experimental design template to keep track of

the details.

Design your experiment

Do you know the difference Do you know the difference between the independent between the independent and dependent variables?and dependent variables?

Independent Variable The

independent, or manipulated variable, is a factor that’s intentionally varied by the experimenter.

Example: We will add 5 mL, 10 mL, or 20 mL of toxic

waste.

Dependent Variable The dependent, or

responding variable, is the factor that may

change as a result of changes made in the independent

variable.Example: the number of

dead fish.

Other Details of the Experiment

A clear procedure so that someone can replicate your experiment.

A list of required materials so they use the correct equipment.

Other Details of the Experiment

In a scientific experiment, the control is the group

that serves as the standard of comparison.

The control group usually is exactly the same as the test groups but the Independent variable is absent or set to “zero”

No toxic sludge in the control!

Control Group

The control group is exposed to the same conditions as the

experimental group, except for the variable being tested.

All experiments should have a control group.

Trials

Trials refer to replicate groups

that are exposed to the

same conditions. This

will eliminate “freak”

outcomes.

ConstantsRemember! In a valid

experiment the only things that should

change from trial to trial are the

independent and dependent variables!

Can you think of some Can you think of some constants for this constants for this

experiment?experiment?

Collect and Analyze ResultsData should be clear

and organized.

A Data table should be drawn BEFORE the

experiment is conducted.

Toxic waste and fish mortality

Amt. of waste

1 2 3 AverageAverage

deathsdeaths

0 mL 1 0 0 0.33

5.0 mL 2 1 2 1.7

10.0 mL 5 4 6 5

20.0 mL 8 11 9 9.3

Number of dead fishNumber of dead fish

TrialsTrials

Control group

Can you accept or reject Can you accept or reject your hypothesis?your hypothesis?

Communicate the Results

You now have hard data that supports your hypothesis.

This is hard to argue against!