AN ORGANIZED APPROACH TO SOLVING PROBLEMS

SCIENTIFIC METHOD

Scientific Method

Organized problem solving• Not a single method

Steps of the Scientific Method

1. Define the Problem2. Collect Information About the Problem3. Form a Hypothesis4. Experiment5. Collect Results6. Conclusion7. Repeat

Step 1. Problem

What are to trying to find out? - Usually based on observations - stated as a question

Example: I notice that on warm nights crickets seem

to chirp more often

Problem = Does temperature affect the rate of cricket chirps?

Step 2. Collect Information About the Problem

Information can be gathered from: - your own observations

- published research textbooks, articles, internet etc…

Step 3. Form a Hypothesis

A possible solution to your problem

Must make a prediction

Must be possible to be disproved - UFOs exist is not a scientific hypothesis

because it is impossible to disprove

Formal Hypothesis

A formal hypothesis used in an experiment should be stated in If…Then form.

- It relates directly to the experiment to be conducted and explains the expected outcome

-If I do this…..then that will happen.

Example: If I raise the temperature I keep crickets in, then they will chirp more.

Step 4. Test Your Hypothesis-Experiment

Experiment must be controlled

- tests only one thing at a time

A controlled experiment compares a control group with an experimental group

The control group provides a normal standard against which the biologist can compare results of the experimental group.

The experimental group is identical to the control group except for the one factor being tested

- the variable being tested is the independent variable

Experimental Design

Needs to be repeatable

Should test a large sample

Should be without bias

Variables

Variable = anything that can change in an experiment

Controlled variables = What do I keep the same?

Independent variables = What do I change?aka Manipulated variables

Dependent variables = What do I measure? aka Responding variables

Question Independent Variable(What I change)

Dependent Variables (What I observe)

Controlled Variables (What I keep the same)

How much water flows through a faucet at different openings?

Water faucet opening (closed, half open, fully open)

Amount of water flowing measured in liters per minute

•The Faucet •Water pressure, or how much the water is "pushing" "Different water pressure might also cause different amounts of water to flow and different faucets may behave

Control Group Experimental Group

20 crickets grown in a 10 gallon aquarium

12 hours of light/day

Fed 5 g Acme Cricket Food

Kept at 60 degrees F

20 crickets grown in a 10gallon aquarium

12 hours of light/day

Fed 5 g Acme Cricket Food

Kept at 80 degrees F

Cricket Experiment

Step 5 Data and Results

Data = observations or measurements - Quantitative = number data 10 chirps/minute - Qualitative = observations color changed to orange

Results = Processed data – makes the meaning of the data more clear. Allows you to see trends or patterns. Calculate an average, graph of data etc..

Graphing Your Data

Independent Variable- the factor that is changed before the experiment begins. It goes on the x-axis. Sometimes called manipulated

Dependent Variable- the factor that you ran the experiment to measure, sometimes called results. It goes on the y-axis. Sometimes called responding

Sample Graph

Dependent Variable: on the Y Axis

Independent Variable on the X Axis

Conclusions

Was your hypothesis correct? - do the results support your hypothesis What are possible sources of error? What next? – What question could you study

next? Why is this important?

Repeat Your Work/Publish

Repeat experiment to confirm your results.

When scientists have completed their work, they publish their results - this informs other scientists of their findings

Theory

A hypothesis that has been tested repeatedly and shown to be correct becomes a theory

Theories can explain current observations and predicts new observations

A theory is as close to certainty as you get in science

Vocabulary to Know and Love

hypothesisexperimental groupcontrol groupvariablecontrolled variablesindependent/manipulated variableDependent/responding variabledataquantitative dataqualitative dataResultstheory