1. Scientific Methodology

2. Science is… a way of knowing about the natural world.
a process using observation and data to investigate and understand our universe.

3. Scientific Methodology
based on observation and interpretation of physical evidence
subject to strict, repeated testing and peer review

4. Observation vs. Inference

5. Observation use one or more of your senses
Good observations are accurate (exact) and objective (unbiased)
Observations are either qualitative (no #’s) or quantitative (uses #’s)

6. Tell if the following are accurate and objective
Observation
Tell if the following are accurate and objective
16 students were on-time to class, and
five students were tardy
Half the class was late
The funniest people showed up first
accurate & objective
inaccurate
subjective

7. Tell if the following are qualitative or quantitative:
Observation
Tell if the following are qualitative or quantitative:
The door is blue
There are three doors in the room
The floor tiles are shiny
The floor tiles are 12”x12”
qualitative
quantitative
qualitative
quantitative

8. Inference when you explain or interpret an observation
should be reasonable (makes sense)
some inferences are unreasonable (far-fetched)

9. inference, unreasonable
EXAMPLES
I see football players wearing uniforms,
they must have a game today.
they must like string cheese.
observation
inference, reasonable
inference, unreasonable

10. The plant is growing in soil
Observation or Inference?
The plant is in a pot
The plant is green
The plant is growing in soil
The plant has leaves
The plant has roots
The plant uses water
observation
inference

11. Self Check What two qualities make an observation scientific?
Can you write a scientific observation about the classroom?
How is an inference different from an observation?

12. Observations lead to Questions
A scientific Question or Problem arises from our observations.
Observation: My dog is shedding more than usual.
What kinds of questions
might you ask after this
observation?

13. Hypothesis
A hypothesis is an educated guess as to what you think the answer to your question might be.
Good hypotheses are reasonable and evidence based.

14. Experiment
Determine a Procedure to test whether hypothesis is correct.
The outcome must be measureable (quantifiable).

15. Experiment
When testing, it is important to perform a controlled experiment.
Many experiments have an “experimental group” and a “control group”.
The two groups are treated EXACTLY alike except for the ONE variable being tested.
A student runs an experiment to see which fish food makes fish grow faster.
What variables exist between the two groups?

16. Experiment
The control group is the baseline, or standard, against which you measure the effect of the introduced variable.
The experimental group is the group into which you introduce one varying factor (variable). + +

17. Experiment
For example, in an experiment to test the effects of a memory-enhancing drug, there would be a control group, consisting of normal, everyday people…
… while the experimental group is given a pill that is intended to improve their memory. + +

18. Experiment
Nearly all experiments have variables – or factors that can affect an experiment.
There are three types:
independent (manipulated)
dependent (responding)
controlled variables

19. Experiment Independent (manipulated) variable
the thing that someone actively changes,
What you are testing
the “cause”
Dependent (responding) variable
the thing that changes as a result of the independent variable
The thing you measure
the “effect”

20. Experiment EXAMPLE In our memory-enhancing drug experiment…
independent variable = (what we test)
dependent variable =(what we measure)
pill given to members of the experimental group
memory of members in the experimental group

21. Experiment
control variable = any factors that could have an affect on your experiment.
In the memory experiment, what factors do you need to control, so we know the ONLY thing changing memory is the pill?
The people need to be the same age, in case younger brains are better at memory
People need to be around similar intelligence levels, it could affect the results of the memory test
The test: both groups must be given the same test in order to compare.

22. Data DATA Data must be measurable and accurate!
Asking the participants if they think their memory is better
Not accurate, subjective
Giving a test before and after, and comparing scores
Accurate, objective

23. Analysis!
ANALYSIS
Examine the data from your experiment, looking for trends, patterns, or any other evidence that can lead to a reasonable conclusion

24. Analysis
If the expected results are obtained, the hypothesis is supported (but not proven).
If the expected results are NOT obtained, the hypothesis is null.

25. In the case of our memory-drug experiment:
Analysis
ANALYSIS
In the case of our memory-drug experiment:
We would look at our data and try to determine if the memory of the people in our experimental group was any better (or worse) than the memory of those in our control group +

26. Conclusion Restate your hypothesis
State whether your prediction was confirmed
Explain your results.
When writing a conclusion for labs:
Include discussion of errors
Include Future Research ideas

27. Peer Review / Communicate Results
Finally, results are shared so that other experts can replicate the experiment and look for flaws or problems.