1. Scientific Method

2. Steps in the Scientific Method
Problem / Question
Observation
Hypothesis
Experiment
Data Collection
Conclusion
Retest

3. 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) Form a Conclusion
7) Retest

4. Observations Gathered through your senses
A scientist notices something in their natural world

5. Observations
An example of an observation might be noticing that many salamanders near a pond have curved, not straight, tails

6. Hypothesis A suggested solution to the problem. Must be testable
Sometimes written as If…Then… statements
Predicts an outcome

7. Hypothesis
An example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live.

9. A procedure to test the hypothesis.
Experiment
A procedure to test the hypothesis.

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

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

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

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

14. What is the Purpose of a Control?
Controls are NOT being tested (they remain the same/normal )
Controls are “standards” used for COMPARISON

15. Other Variables
The factor that is changed is known as the independent variable.
The factor that is measured or observed is called the dependent variable.

16. Example of Constants & 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.

17. 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 constant / control variable.

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

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

20. Data Results of the experiment
May be quantitative (numbers) or qualitative
Precision / accuracy

21. Step 5 - graphs, data tables, ratios, frequency/
percentages, or totals
Examples: *
Blonde Hair
Brown Hair
Red Hair
Black Hair
1st 6 1 3
2nd 9 7
3rd 5 2 4
* 3 of 6 kittens are white = 3/6 = 1/2 = 50%
* 30 m&m’s in bag, 10 are brown > :1 ratio

22. Step 5 – Data is always measured in metric units
S.I. – International System of Units
length – km, m, cm, mm
mass – kg, g, mg
volume - L, mL, cc or cm3
temperature - oC or oK
time - seconds, minutes, hours, days, years…

23. Data
Must be organized
Can be organized into charts, tables, or graphs

24. •Graphs help us visualize numerical data.
Why Do We Use Graphs?
•Graphs help us visualize numerical data.
•There are several different types of graphs:
–Bar graphs
–Pie graphs
–Line graphs

25. Bar graphs are used to show a comparison of multiple objects•

26. Pie graphs are used to compare the parts of a whole•

27. Line Graphs
Line graphs are used to show the relationship between variables.

28. Conclusion
The answer to the hypothesis based on the data obtained from the experiment

29. In order to verify the results, experiments must be retested.
-Results that are the best explanation for validated data may become a theory.

30. Step 6 – Conclusions – (may or may not prove your hypothesis.)
Theory –best tested explanation of natural events;
however, cannot be ‘proven’
Law - tested and proven to be factual time
after time

31. 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) Form a Conclusion
7) Retest

32. Review

33. Controls and Variables

34. Valid Experiments