1. WELCOME TO BIOLOGY LESSON
It’s time to study about…

2. Scientific Method

3. How do scientists know what they know?
Why is the sky blue?
Why does it rain?
How did people live in the past?
How old is the Earth?

4. The Answer….
Scientist use SCIENTIFIC METHOD to answer questions and solve problems.

5. The Scientific Method
A. Definition B. Steps

6. A. Definition
A common misperception of science is that science defines "truth".  Science does not define truth, but rather it defines a way of thought.  It is investigation process of rational concepts that can be tested using observation and experimentation to answer questions.  This process is called the scientific method

7. A. Definition
The scientific method is the only scientific way accepted to back up a theory or idea. This is the method on which all research projects should be based. The Scientific Method is used by researchers to support or disprove a theory.

8. B. Steps in the Scientific Method
Observation
Question
Hypothesis
Experiment
Data Collection
Data Analyze
Conclusion
Report Result

9. Observations
You observe something in the material world, using your senses or machines which are basically extensions of those senses.
A scientist notices something in their natural world

10. Observations
An example of an observation might be noticing : salamanders that develop under acid rain conditions show a greater number of   developmental abnormalities
Ah…look at this!!!

11. Questions
You ask a question about what you observe. State the problem or question.
Example: "Does acid rain affect the development of salamanders?"

12. Questions The problem should be:
Measurable (submits to the scientific method)
Clearly and concisely stated
If necessary, divided into simpler measurable components

13. Hypothesis
A hypothesis is an educated guess about solving the stated problem/question.
You think the suggested solution/answer to the problem/question.
Must be testable.

14. Hypothesis Sometimes written as If…Then… statements
Predicts an outcome.
A hypothesis is not valid if it cannot be tested somehow
Controlled experiments
Gathering more data

15. Hypothesis An example of a hypothesis might be:
“Salamanders that develop under acid rain conditions show a greater number of developmental abnormalities than salamanders that develop in unpolluted waters”.

16. Experiment A procedure to test the hypothesis.
You figure out a way to test whether hypothesis is correct.

17. Variable – factor in the experiment that is being tested

18. A good or “valid” experiment will only have ONE variable!

19. Controls and Variables

20. Scientific Experiments Follow Rules
An experimenter changes one factor and observes or measures what happens.

21. The Control Variable
The experimenter makes a special effort to keep other factors constant so that they will not effect the outcome.
Those factors are called controlled variables.

22. What is the Purpose of a Control?
Controls are NOT being tested
Controls are used for COMPARISON

23. Other Variables
The factor that is changed is known as the independent variable/manipulated variable.
The factor that is measured or observed is called the dependent variable/responding variable.

24. Example of Controls & Variables
For example, suppose you want to figure out the fastest route to walk home from school.
You will try several different routes and time how long it takes you to get home by each one.
Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.

25. What are the Variables in Your Experiment?
Varying the route is the independent variable
The time it takes is the dependent variable
Keeping the same walker throughout makes the walker a control variable.

26. One more thing… it is best to make several trials with each independent variable.

27. Valid Experiments

28. Remember: To be a Valid Experiment:
Two groups are required --- the control & experimental groups
There should be only one variable

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

30. 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

31. Data Collection Results of the experiment
May be quantitative (numbers) or qualitative

32. Data Collection 2 Types of Data
Quantitative Data- expressed in numbers by counting or measuring
i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters.
Qualitative Data- are descriptive and involve characteristics and cannot be counted.
i.e. white maggots covered the meat, leaves were all wilting
Quantitative Data is easier to analyze because it is less objective

33. Quantitative or Qualitative???

34. Data Analyze Must be analyzed Always rely on facts not comparisons.
Can be organized into charts, tables, or graphs
Put your data into word

35. Conclusion
The answer to the hypothesis based on the data obtained from the experiment.
Statistics may be used to evaluate data.

36. Conclusion
If a hypothesis is proven to be true over and over it may be called a law or principle.
If a hypothesis seems to be true but is unable to be directly tested, it becomes a theory.

37. Report Result
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

38. In order to verify the results, experiments must be retested.

39. Retest Repeat the experiment! Sometimes results are unexpected.
John Needham challenged Redi’s experiment and designed his own to show that spontaneous generation CAN occur under certain circumstances.
Lazzaro Spallanzini designed a slightly different experiment to improve on Needham’s work.
Repeat the experiment!

40. Can you put these steps in order?
Define the Problem
Analyze Data
Report Results
Make an Observation
State the Hypothesis
the Problem
Determine Limitations

41. 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

42. Review Thinking Like a Scientist !!!
Look around the classroom and make an observation…!!!
Use the Scientific Method to test hypothesis.

43. Solving a Problem 1) Identify a Problem
2) State Observations about the problem
3) Form a Hypothesis about the problem (if…then…)
4) Design an Experiment to test the hypothesis
5) Collect Data
6) Analyze Data
7) Form a Conclusion
7) Report result

44. THANK’S FOR YOUR ATTENTION