the scientific method

The Scientific Method

Unit 1: The Scientific Method

Chapter 1-1 & 1-2

What is Science? Science is a method of thinking

about the natural world. Biology is the scientific study of

life.

Scientific Method The scientific method is a

procedure scientists use to seek answers to questions.

PROBLEM

HYPOTHESIS

EXPERIMENT

RECORD DATA &ANALYZE RESULTS

ACCEPT HYPOTHESIS

THE SCIENTIFIC METHOD

FORM A NEW HYPOTHESIS

REJECT HYPOTHESIS

REPEAT THE WORK

CONCLUSION

1. Identify a ProblemObservations are

descriptions about the way something is or the way things happen

From these observations, a question is formed about why or how

Example: Identify a problem Barney observes:

–When I drink Coke, I burp a lot.

He asks Professor Frink:– Why does Coke cause

burping?

Professor Frink explains:– You can do background research

to help you know more• Look online about the physiology of

burping

Example: Identify a problem

Wikipedia - not always 100% accurate, but a good start for background information

carbon dioxide in drinks causes gas pressure to build in the stomach

A Hypothesis is a prediction that may provide an answer to the question– The hypothesis must be

“testable”– The hypothesis must be written

in the form of an “If…, then…” statement

2. Create a Hypothesis

Example: Create a Hypothesis

If people drink Coke, then they will burp more.Student example(s)…….

Hypothesis vs. Theory Hypothesis: is an educated guess

that can be tested and may or may not be true

Theory: a well-tested hypothesis that is supported by many types of observations– In science, theories are nearly facts– Ex. Theory of Evolution, Theory of Relativity,

Cell Theory

3. Controlled ExperimentTest the hypothesisProcedure—the steps

followed during an experiment

Well designed experiments have a control group and experimental group(s)

Subject

Subjects

Control Group: all variables are kept the same (constant)– Used for comparison

Experimental Group: all the same variables except the one thing you are testing

The experimental group drink Coke.

The control group drink water.

Independent Variable

Control

Variables: anything that can influence the outcome of the experiment

– Examples: age of subjects, health of subjects, having food or drinks before the experiment

Independent Variable: What you are testing– (The variable that is changed)

Dependent Variable: what is measured or observed– The variable that changes

because of the independent variable

Example: Experiment Independent Variable: type of

beverage

Dependent Variable average number of burps

Independent Variable

Control

4. Record Data & Analyze Collect & record Data

(information)– Qualitative data: descriptions– Quantitative data: numbers

• Data can be recorded in a table Analyze the data by graphing

it– Bar graphs: show comparisons– Line graphs: show changes over

time

Example: Recording DataAverage # of Burps

Control Group: Water

2

Experimental Group:

Coke

6

Independent Variable Contro

l

Dependent Variable: what you measure

Analyze the Results: Bar Graph

Y-axis = Dependent

Variable

X-axis = Independent Variable

Title

Label

Occurrence of Gas Expulsion for Non-carbonated vs. Carbonated Beverages

0

1

2

3

4

5

6

7

WATER COKE

# O

F BU

RPS

Average Number of Burps for Water vs. Coke

Proper units

Type of Beverage

5. Conclusions

The results tell whether the hypothesis was “accepted or rejected”

Example: ConclusionAccept or reject the

hypothesis? –ACCEPT!

Why? –There were more

burps with Coke than with water based on the data and the results of the graph.

When a hypothesis is supported by data from additional investigations, it is considered valid.

When a hypothesis is not supported, it means that we need to go back and ask new questions or identify sources of error in the experiment.

6. Repeat the Work

ACCEPT HYPOTHESIS

THE SCIENTIFIC METHOD

FORM A NEW HYPOTHESIS

REJECT HYPOTHESIS

REPEAT THE WORK

PROBLEM

HYPOTHESIS

EXPERIMENT

RECORD DATA &ANALYZE RESULTS

ACCEPT HYPOTHESIS

THE SCIENTIFIC METHOD

FORM A NEW HYPOTHESIS

REJECT HYPOTHESIS

REPEAT THE WORK

CONCLUSION