Science

The study of nature through observation and experimentation

In studying nature, scientists make observations and then form and test hypotheses

Characteristics of science

Deals with the natural using natural explanations (methodological naturalism)

Rational

Repeatable

Universal (it works regardless of time, place, or country of origin)

What is a hypothesis?

What is a theory?

What is a law?

Can theories become laws or facts?

A falsifiable explanation for a pattern in nature (answers a causal question)

A falsifiable explanation for a pattern in nature. Usually more general than a hypothesis and ALWAYS very unlikely to be incorrect.

A description of a pattern found in nature that always occurs under specific conditions

NO! Theories explain laws and facts

Define causal question

A how or why question that can be answered scientifically

Come up with an example and a non-example of a causal question

Non-example: What color is the sky?

Example: Why is the sky blue?

Questions that can be answered with a yes or no are NOT causal questions

Formulate a hypothesis

Formulate a hypothesis

A controlled medical experiment

What is a control group?

The group that experiences the same conditions as the experimental group except for the factor being tested

Why do valid experiments need a control group?

So alternative explanations can be ruled out

What does a control group allow us to do?

Test the effects of one variable at a time

What is an experimental group?

The group that gets the treatment or the thing the experimenter is testing

Independent variable

The thing the experimenter is testing the effect of

Dependent variable

The thing the experimenter is measuring to test the effect of something else

Define correlation

A relationship between 2 variables, it can be positive (directly proportional, or negative inversely proportional)

Define causation

when one variable affects change in another variable

Correlation does not equal causation

Why does an increase in ice cream consumption cause an increase in drowning?

It doesn’t!

People eat more ice cream when it is hot

People also swim more when it is hot

When people swim, they die

How do we evaluate scientific evidence?

1) How strongly do the results of the research support the claim?

Questions to ask

• Is there a correlation?• How large is the difference between the

means (averages) of what is being measured?

• How much spread is there in the data?• What statistical tests were used

How do we evaluate scientific evidence?

2) What are the limitations of the research methods and/or experimental design?

Questions to ask

• Was there a large sample size?• Were there proper controls?• What controls should have been used?• What was the funding source for the

research?• Were the researchers biased?