What is Science?What is Science?• ScienceScience refers to a method of learning

about the natural world, as well as to the knowledge gained through that process.

• Scientific InquiryScientific Inquiry refers to the diverse ways in which we try to answer questions and solve problems concerning the natural world.

• Observation:Observation: using the five senses to gather information.

• Inference:Inference: an interpretation based upon our observations.

Science is Always Evolving Science is Always Evolving (Changing)!(Changing)!

• Science changes as we acquire new information…and that makes sense! Doesn’t it?

• At one time it was a fact that Earth was flat. We’ve learned some stuff since then.

• This is why it is more accurate to use the terms supported or refuted rather than true or false.

• Objective Statement: a statement of fact.

• The game lasted three hours.

• Subjective Statement: a statement of opinion.

• The game lasted too long!

• Science is objective by nature.

Qualitative vs. QuantitativeQualitative vs. Quantitative

Qualitative Quantitative

Describes QUALITIES…•Purple•Acrid•Salty

Describes QUANTITY•14.745 cm•55 square meters•4 x 104 A.U.

The Scientific Method

1. Ask a question.

2. Develop a hypothesis (If/Then).

3. Experimenting and testing.

4. Collect and organize data.

5. Analyze data.

6. Draw conclusions (substantiate or refute).

7. Retest.

•A HypothesisHypothesis: a possible explanation for observations relating to a scientific question.

•A hypothesis makes a prediction!

•Hypotheses are tested by conducting controlled controlled experimentsexperiments. In this type of experiment, scientists determine how one particular variable affects the outcome.

A Valid Scientific Hypothesis Must A Valid Scientific Hypothesis Must Be Testable!Be Testable!

• If you can’t design an experiment to test a hypothesis…it’s not useful.

• If you develop a hypothesis, test it, and it’s not supported…that’s OK! You’ve still learned from it.

•We test hypotheses using controlled experiments.

• Variable: a factor that can change in an experiment. There are three types…but you knew that right

1.1. Manipulated or Independent Manipulated or Independent Variable:Variable: changed by the scientist (dats you!). You only want ONE of these!

2.2. Responding or Dependent Responding or Dependent VariableVariable:: changes because of the manipulated variable.

3.3. Controlled VariablesControlled Variables: These stay the same during an experiment.

Data are the facts figures and other evidence gained through observation

VariablesVariables• Manipulated or

Independent Variable

• changed or controlled by the scientist.

• Example: The amount of water (in ml) given to a plant daily.

• Responding or Dependent Variable

• changes because of the manipulated variable.

• Example: The measured daily growth of the plant (in cm).

Test Yourself!1. Why don’t we want to have

more than one manipulated/independent

variable in a controlled experiment?

2. What is true of a valid scientific hypothesis?

3. Design an experiment and list your manipulated, responding,

and controlled variables.

Scientific TheoryScientific Theory• A theory is NOT the same as a hypothesis. You’d

be amazed at how many folks don’t understand that…you will not be one of those folks!

• A theory is an explanation for a set of related observations or events based upon proven hypotheses.

• It’s verified over and over by detached groups of researchers (WELL-TESTED).

• In other words…it has been subjected to rigorous testing…everywhere…and the evidence always supports it!

• One scientist cannot create a theory; he/she can only develop a hypothesis.

In general, both a scientific theory and a

scientific law are accepted to be “true” by the scientific community

as a whole. Both are used to make predictions

of events.

Theory v LawTheory v Law

• Ok…it’s like this…a theory ties together (it’s unifying) many related facts, observations, supported hypotheses. It EXPLAINS WHY THINGS HAPPEN, and allows us to make predictions.

• A Law also ties this type of information together, and allows us to make predictions, BUT…IT DOES NOT EXPLAIN WHY?

Check Your HeadCheck Your Head((Take a moment and answer Take a moment and answer

these in your notebook.)these in your notebook.)

1.Why is it inaccurate to say that a scientific theory is “just a theory?”

2.Can one scientist develop a theory on his/her own? Explain please!

Scientific ModelsScientific ModelsRepresentations of objects or systemsRepresentations of objects or systems

1st Type: Physical- An actual 3-D imitation that can be studied.

Limitation: Not exactly like the real thing…for example…a plastic model of a temperate forest doesn’t actually have living inhabitants that interact.

Physical ModelPhysical Model

2nd Type: Mathematical-Numbers, Data, Equations…if you have certain data, you can “plug it into” the model and make PREDICTIONS.

Limitation: It still isn’t the actual event…it’s a prediction and predictions can be wrong.

Mathematical ModelMathematical Model

3rd Type: Conceptual-qualitative models that help to diagram important interrelationships among processes and systems that we study.

Limitation: Again…not the real thing…but helps us understand the real thing.

Conceptual ModelConceptual Model