1. Notes
Scientific Method
How Scientists Work

2. How Scientists Work: Solving the Problems
Much of science deals with solving problems
These problems can be environmental, economic, health related, etc.
No matter what types of problems are being studied, scientists use the same problem-solving steps called…
The Scientific Method

3. Scientific Method Definition
The scientific method is-
A logical and systematic approach to problem solving. 
An organized way of using evidence to learn about the natural world

4. Scientific Method Listing the Steps
Make an Observation
Define the Problem/Question
Research the Problem
State the Hypothesis
Develop Experiment-it’s a test!
Perform experiment
Collect and Record Data
Analyze Data
Communicate the Data-graph
Draw Conclusions
Determine Limitations
Report Results
If needed, Do more investigation

5. 1. Observing Make an observation Use senses to notice
As we all know, frogs have four legs.
Make an observation
Use senses to notice
something unusual that
makes you
CURIOUS!
What’s up with these froggies?

6. 2. Questioning Recognize, state or define the problem
Must be in the form of a question
MUST BE TESTABLE

7. 3. Researching Gather information related to the problem
Read and study what has already been reported on this topic. Someone may have already answered
your question

8. 4. Hypothesizing A hypothesis is: A prediction or possible explanation
Must be an “If, then…” statement, which will include your independent variable and dependent variable
Must be testable
Is based on your research and previous experience

9. Variables in an Experiment
Variables - Factors that can change in an experiment
Controlled Variables - all the variables that a researcher keeps constant
Independent (Manipulated) Variable- factor in an experiment that a scientist purposely changes
Dependent (Responding) Variable - factor in an experiment that may change because of the independent variable

10. 5. Experimenting Goal of an experiment is to test the hypothesis
You must perform
your experiment
many times to gather
evidence (at least 3 times)

11. Setting up a Controlled Experiment
In a controlled experiment, only one factor is changed at a time.
Independent variable: the factor that is deliberately changed
Dependent variable:
the factor that the scientist wants to observe; it changes in response to the independent variable

12. Control and Experimental Groups
Control Group- used as a standard for comparing. This group is left alone- or “under normal conditions”
Experimental Group-the group containing the factor that has been changed. This group receives the independent variable.

13. What do I do next???
The steps a researcher will follow to test their hypothesis is their PROCEDURE: Must be a numbered list of directions
Must include all the variables: independent, dependent and controlled/constants.
The more controlled variables, the more VALID the results are
They MUST know what they are going to measure (DEPENDENT) and how

14. Measure???
Must use the correct tool for measuring-thermometer, triple beam balance, graduated cylinder, ruler, stop watch
Must know what you are measuring: time, mass, volume, temperature
Keep track of all of your data in a TABLE

15. 6. Collect and Record Data
Data: Observations and measurements made in an experiment
Quantitative - observations that involve measurements or numbers; i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters
Qualitative - observations that do not involve numbers, are of a descriptive nature i.e. rabbits fur color changed, leaves were all wilting

16. 7)Communicate Data All data must be put into a GRAPH.
The type of graph you use must reflect the data:
Line graph- Shows changes as time is going by
Bar graph- Comparing things that aren’t related
Pie graph- Percents

17. 8. Analyze the Data Examine data tables, charts, and graphs
Examine experimental notes
Look for trends, patterns, and averages
What does the data show
Put your data into words

18. 9. Draw Conclusions
Accept or reject the hypothesis, based on your experimental results.
If accepted, support your conclusion with specific, numerical data.
If rejected, explain why & go
back to the drawing board-
either change your experiment
or change your hypothesis

19. 10. Determine Limitations
Scientists look for possible flaws in their research
They look for faulty (inaccurate) data
They look for experimental error or bias's
They decide on the validity of their results
They make suggestions for improvement or raise new questions

20. 11. Publish Results Communication is an essential part of science
Scientists report their results in journals, on the Internet, or at conferences
This allows their experiments to be evaluated and repeated
Scientists can build on previous work of other scientists

21. Can you put these steps in order?
Define the Problem 2
Analyze Data 7 10 8 6
Report Results
Make an Observation
State the Hypothesis 5 1 4
the Problem 9 3
Determine Limitations

22. Steps of Scientific Method in order1
State the Hypothesis
Make an Observation
Define the Problem 2
the Problem 3 4 5 6
Analyze Data 7 8 9 10
Report Results
Determine Limitations

23. Scientific Theory
A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers

24. Scientific Law
Scientific Method
Scientific laws represent the cornerstone of scientific discovery
They must be simple, true, universal, and absolute
If a law ever did not apply, then all science based upon that law would collapse

25. Science at Work
Let’s look at an example of the Scientific Method using Francesco Redi’s Experiment on Spontaneous Generation
He was trying to disprove the idea of Spontaneous Generation
Francesco Redi (1668)

26. Stating the Problem Example: How do new living things come into being?
Spontaneous generation once commonly accepted
Redi wanted to show what caused the appearance of maggots (and then flies) on meat

27. Belief based on prior observations
If leaf lands on water it becomes a fish
If a bale of hay is left in barn, it produces mice
Muddy soil gives rise to frogs
Meat hung out in the market is the source of flies

28. Forming a Hypothesis Redi’s Hypothesis: Flies produce maggots.
How could he test this?
Through a controlled experiment

29. Redi’s Controlled Experiment
Redi used two groups of jars
Jars that contained meat and no cover
Jars that contained meat and gauze cover
Jars with meat
Uncovered jars
Covered jars

30. Variables in Redi’s Experiment
Controlled Variables: jars, type of meat, location, temperature, time
Manipulated Variables: gauze covering that keeps flies away from meat

31. Let’s think about this.…
Which is the control group?
Which is the experimental group?
Uncovered jars
Covered jars
Two groups of Jars with meat
Uncovered jars
Covered jars

32. Redi’s Experiment on Spontaneous Generation
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: Flies produce maggots.
PROCEDURE
Manipulated Variables:
gauze covering that
keeps flies away from
meat
Uncovered jars
Covered jars
Several
days pass
Maggots appear
No maggots appear
Responding Variable:
whether maggots
appear
CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.
Controlled Variables:
jars, type of meat,
location, temperature,
time