The Scientific Method

Scientific Method• An organized

approach used to solve a problem or solution.

• A list of steps that is not set in stone, rather it is used as a guide or frame for problem solving.

Hypothesis versus Theory

Hypothesis:• Explanation of an

Observation• Outcome • If I do….then I

expect……• correct or

incorrect

Theory:• Established idea

• Factual

• Experiments

• Data

Controlled Experiments

Control:• the part of the

experiment that is left alone or “natural”.

• Used to compare back to

Experimental • The part of the

experiment in which a factor or variable is changed.

Variables

• Variables are parts of an experiment that can be changed.

• Control (constant variables): factors in an experiment that are NOT changed.

Experimental Variables:

• Independent (manipulated) Variable: factors in an experiment that are changed.

• Good experiments have only ONE manipulated variable.

• Dependent (responding) Variable: responds to changes in the independent variable.

• Example: Measure growth in height as a result of no fertilizer

Observation vs. InferenceObservation• Description of objects,

eventsevents• May include data from

all five senses (touch/texture, smell, taste, sight, sound)

• Could be drawings, diagrams, written words

• Do not include opinionsopinions.

Inference

• Drawing conclusionsconclusions based on observations

• Often provide a reasonreason for the event/object being observed.

• Based on previous knowledge.

Data versus Opinion…...

Data:

• Factual

• Measurable

• Replicates

Opinion:

• Personal

• Inferences versus observations?

• bias

Scientific Data Must Be…..

• Measurable

• Quantifiable

• NOT opinion or judgment

7 Steps of the Scientific Method

• Problem or Question• Research• Hypothesis• Experiment• Collect and Analyze

Data• Conclusion• Communicate

Results

Identify the question• What question is

being answered, problem solved, or hypothesis tested?

• Leads to observations

• For example, “How many drops of water fit on a penny?”

Background research• Research the problem

using quality sources.

• Ask questions and read everything you can about the problem you have chosen.

• Study the method of measurement you will use to quantify your observations if it is one you are not familiar with.

State you hypothesis• Construct a Hypothesis: A

hypothesis is an explanation of an observation about how things work:

• "If _____[I do this] _____, then _____[this]_____ will happen."

• You must state your hypothesis in a way that you can easily measure, and of course, your hypothesis should be constructed in a way to help you answer your original question.

Design an experiment• The experiment tests whether

your hypothesis is true or false. • It is important for the experiment

to be a fair test. • Conduct a fair test by making sure

that you change only one factor at a time while keeping all other conditions the same.

• Repeat the experiments several times to make sure that the first results weren't just an accident.

Collect and Analyze data• Once the experiment is complete,

analyze the data to see if your hypothesis is true or false.

• Scientists often find that their hypothesis was false, and in such cases they will construct a new hypothesis starting the entire process of the scientific method over again.

• Even if they find that their hypothesis was true, they may want to test it again in a new way.

CONCLUSION• A conclusion summarizes how the results

support or contradict the original hypothesis.

• Summarize the results in a few sentences and use this summary to support or refute the hypothesis.

• Include key facts from your background research to help explain your results as needed.

• Summarize and evaluate your experimental procedure, making comments about its success and effectiveness.

• Suggest changes in the experimental procedure (or design) and/or possibilities for further study.

Communicate results• Communicate the results

to others in a final report.– publishing their final report

in a scientific journal– presenting their results on

a poster at a scientific meeting.