Hypothesis
●Hypothesis is possible explanation about the
cause of an event or relationship among
things. It is frequently formulated as an
“If/then” statement.
●Must be testable and falsifiable
○ Falsifiable = must be able to be shown to be untrue.
Theory
Theory- an extremely well supported explanation
of how some aspect of the natural world works.
A theory incorporates: facts, laws, inferences
and tested hypotheses
Theory is a unifying explanation for MANY
observations, inferences, and tested
hypotheses.
Theory
Scientific theories are the ideas about which
scientists are most certain.
Theories are the bedrock of our understanding
of nature.
EXAMPLES Anyone?
Theory
Well tested ideas
supported by diverse
lines of evidence and
capable of explaining
observations and
predicting new ones.
Examples:
Cell Theory
Theory of Relativity
Gravitational Theory
Germ Theory
Quantum Theory
Electromagnetic Theory
Chaos Theory
Theory of Plate Tectonics
Atomic Theory
Theories explain how nature works.
Is anything wrong with the following sentence?
Explain why or why not.
Bert: “I think a lot of people have missed school
lately because the flu is going around. What’s your
theory?”
Science
⦿ Is
uncertain
⦿ Is always changing
⦿ Is
Collaborative
⦿ Is about Questioning and Observing
Uncertainty
⦿ Scientists make
observations of nature. A
hypothesis is a possible explanation for an event
or set of observations.
⦿ One can never be sure that they have observed
all evidence, and it is often possible to interpret
evidence in different ways
Uncertainty
⦿ Therefore, a
scientist can never be certain that a
hypothesis is correct.
⦿ BUT, a hypothesis can always be tested
Science is Always Changing
⦿ Science
does not create absolute fact
⦿ A hypothesis is only
as strong as the evidence
that backs it up.
⦿ A hypothesis must be rejected if new evidence
does not support it
⦿ A scientist's job is to “falsify”
hypotheses.
Science is Always Changing
The scientist’s number one priority is to find
evidence that contradicts a hypothesis.
A scientist seeks to reject hypotheses.
What happens to a hypothesis when the evidence
disagrees with it?
Science is Always Changing
Falsification
A hypothesis that is inconsistent with the
evidence has been shown to be false.
Thus, that hypothesis is REJECTED or modified
and re-tested.
This is HOW we learn about the world around us.
This is how science moves forward.
Science is Collaborative
⦿ The power of
thinking is strengthened by
including as many perspectives as possible.
Observing and Questioning
⦿ Science
can only study things that can be
observed and tested.
⦿ Observations can be made directly with the
senses or with help from things like microscopes
Observing and Questioning
⦿A
hypothesis is an attempt to explain
observations.
⦿ One must be able to test a hypothesis.
Provisional Assent
➢ Scientific
Ideas Can Only Be Proven Wrong
➢ A theory stands because observations or
experimentation never proves its tenets wrong.
➢ This doesn’t prove the theory is correct – only
that its never been proved wrong.
➢ In this sense, scientific knowledge is provisional.
The Scope and Limitations of Science Are More Than An
Academic Issue
Summary points of the December 20, 2005 Kitzmiller v. Dover Area School
District ruling:
Is this the final word on evolution and alternatives in the classroom?
Hardly.
The Scope of Biology
some of
this
all of this
Biology and its study are arranged hierarchically. New properties (emergent
properties) arise at each level of organization.
Evolution Is Biology’s Unifying Principle
⦿ Is
anything wrong with the following situation?
⦿ There is a law that requires that science classes
in Louisiana teach that supernatural forces may
have created the world and the life in it.
Science is Uncertainty
⦿ Many
of the things that scientists observe cannot
be experienced directly
⦿ Scientists must put together pieces of evidence.
They use indirect evidence.
⦿ They make a guess called
a hypothesis
How's that?
⦿ Did you know geese grow on trees?
You are now less d$#&*