1. Scientific Method: steps used by scientists to solve problems

2. Steps in the Scientific Method/Experimental Design
Observation
Hypothesis
Experiment
Data Collection/Results
Conclusion
Repeated Trials/Retest

3. 1. Observations Gathered through your senses
A scientist notices something in their natural world
Without explanation or interpretation.

4. What is an observation about this frog?
An example of an observation might be noticing that many salamanders near a pond have curved, not straight tails OR
What is an observation about this frog?

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

6. 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.

7. A procedure to test the hypothesis.
3. Experiment
A procedure to test the hypothesis.

8. Experiment vocabulary
Variable – things that change
Constants -things that
stay the same

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

10. Variables
The factor that is changed purposefully to be tested is known as the independent variable. (Ask yourself, what am I changing?)
The factor that is measured or observed is called the dependent variable.

11. What is the Purpose of a Control?
Control groups are NOT being tested (it’s the one you don’t do anything to)
Controls are used for COMPARISON

12. The Constant
The experimenter makes a special effort to keep all factors the same except the IV so that they will not effect the outcome.
Those factors are called
constants.

13. Example of Constants & Variables
In our example, suppose you hypothesize that salamanders near ponds have curved tails.
You will observe salamanders near and away from a pond and count the number of curved and straight tails in each location.

14. What are the Variables in Your Experiment?
The location (near or away from a pond) is the independent variable
The number of straight and curved tails is the dependent variable
Collecting salamanders at both locations on the same day is a constant. What are some other constants?

15. To be a VALID experiment:
Two groups are required: the control & experimental groups
There should be only one independent variable

16. Let’s review vocabulary!

17. 4. Data/Results Must be organized
Can be organized into charts, tables, or graphs

18. Data/Results Results of the experiment
may be quantitative (measurable/
numbers) or qualitative (descriptive)

19. Quantitative OR Qualitative
The rose is red.
Shawn is wearing a Hurley t-shirt.
There are 25 students in this class.
Water freezes at zero degrees Celsius
The bug looked dead
This watermelon contains a liter of water.

20. Graphs: Bar or line
Use bar graphs for comparing data and when you have only one set of numbers
ex. Graphing # of seeds that grew in different types of soil
Use line graphs to display data over time and when you have two sets of numbers
ex. Graphing number of people over the years

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

22. In order to validate/verify the results, experiments must be retested.
Repeated Trials
In order to validate/verify the results, experiments must be retested.

23. Theory vs. Law
Theory: when many experiments show the same conclusion, the hypothesis can become a theory.
Theories are NOT proven!!
Law: fact of nature ex. gravity

24. Can you name the steps of the scientific method?
Now write down 4 quantitative and 4 qualitative statements that describe you.