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Today we are going to learn about…
THE SCIENTIFIC METHOD!
The fundamental cornerstone of ALL SCIENCE!!!
Today’s ResourcesHandout on the Scientific Method
Worksheet on the Scientific Method
Prentice-Hall p. 8 – 14, 1060 - 1063
Words we will understand by the end of today…
Observation
Inference
Hypothesis…and the Null Hypothesis
Data – quantitative and qualitative
Variables
Controlled experiment
Control group
Back to our sewer lice….With 2 colleagues, make as many observations
and inferences about your sewer lice
You have 5 minutes….
What’s the difference between an observation and an inference?
Inference: Conclusion based on evidence and reasoning
Reasoning – but not fact
Logical – but not necessarily true…
Inductive: Specific observations extrapolate to general conclusions
Deductive: General observations extrapolate to specific results…
Based on our observations, we formulate a research question
Our research question is presented as a hypothesis, based on our biological reasoning
We typically present the Null hypothesis
So why do all experiments require a hypothesis?
‘If………..then………………’
We must have a principle that we can objectively test
We generally state the Null Hypothesis for cause-and-effect relationships
Identify the experimental VARIABLES
Dependent – what you measure (X-Axis)
Independent – what you change (Y- axis)
Controlled – what remains constant
(Uncontrolled – variables which may be hard to control)
Ideally you should have all variables controlled, excepting one dependent and one independent variable
When does a hypothesis become a theory?
When a hypothesis is repeatedly confirmed by experiment and observation (USING THE SCIENTIFIC METHOD), it may become generally considered as a THEORY
THEORIES are the most reliable, rigourous, and comprehensive form of scientific knowledge
Some well known scientific theories:
Cell theory
Evolutionary theory
Theory of relativity
Climate change theory
Designing a controlled experiment
1. Formulate a focused research question
2. Identify ALL of the relevant variables (independent, dependent, controlled, uncontrolled)
3. Decide how to manipulate the independent variable – range
4. Decide how many repeats of the experiment you need to do
5. Decide if you are including a control group
1. Control Group
2. Independent Variable
3. Dependent Variable
4. What should Smithers' conclusion be?
5. How could this experiment be improved?
Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work.
Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.
No special juice
The juice
Number of papers stapled
Stay off the juice! (The juice doesn’t work)
Identify the-16. Control Group
17. Independent Variable
18. Dependent Variable
19. Explain whether the data supports the advertisements claims about its product.