Tuesday means….

Tuesday means….

Homework collection…

Let’s remember…

What are the (8) characteristics of living

things?

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….

Observations Inferences

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

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

How much data is enough?

The classical five by five model

5 different test groups

Repeat the test on each group 5 times

Answer Q 1 – 4 on Page 2

Answer Q 1 on Page 3

Answer Q 1 on Page 4

You have 10 minutes…

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.

20. Describe how Lisa would perform this experiment. Identify the control group, and the independent and dependent variables in your description.