11/8/2015 Nature of Science. 11/8/2015 Nature of Science 1. What is science? 2. What is an observation? 3. What is a fact? 4. Define theory. 5. Define.

04/20/23Nature of Science


1. What is science?2. What is an observation?3. What is a fact?4. Define theory.5. Define law.6. What is a hypothesis?

Pre-Test


• Tentative, uncertain• Cannot solve all kinds of problems• One way of knowing about the universe • Attempts to explain natural phenomena in

natural terms• Deals only with facts and the operation of

natural laws• Involves rigorous, systematic use of

observations and logic to attempt to disprove or invalidate possible solutions, not prove them

Science


Most fundamental concept is CAUSE AND EFFECT

Deals only with natural (physical) universeBased on repeatable observable factsRelies on observationConviction that natural processes have natural

causesSecond major characteristic is hypothetico-

deductivethinkingScience is a thoroughly human enterprise

Characteristics


• Observation refers to the ability to sense a natural phenomenon through careful, analytical, attention

• e.g.-noticing that your cat wakes you at 5:30 AM every morning is an observation.

• Various tools used• Makes use of all human senses

Observation


• Facts = verifiable, repeatable observations

• i.e.- information that has objective reality arrived at through observation

• Science demands that there be general agreement on the facts

• e.g., it is a fact, (it is true) that, if I drop a bowling ball from the roof of this building, it will fall to the ground. This act can be repeated many times, by many individuals, with all agreeing on the result

• It is a fact that a gallon of water weighs 8.34 lbs

Facts


1. What is the most fundamental characteristic of science?

2. What are the other characteristics of science?

3. What is a fact?4. Give an example of a fact.5. What does the term, observation,

mean?6. Give an example of an observation.

Quiz


Most fundamental concept of

science is that of cause and

effect: i.e., A causes B;Scientists are never satisfiedwith simply describing events

inthe natural world; strive toshow relationships betweenevents and to explain them

Cause & Effect?From http://www.702communications.com/~ahill/Parent.html

Cause & Effect


• Inductive reasoning - specific to the general • Deductive reasoning - general to the specific• Deductive reasoning starts with general rule or

premise, then make conclusion about something specific.

Hypothetico-Deductive Thinking

•e.g:•All turtles have shells•The animal I have captured is a turtle•I conclude that the animal in my bag has a shell


• Inductive reasoning - specific to the general • Making conclusion based on set of empirical data.

If I observe that something is true many times, concluding that it will be true in all instances is a use of inductive reasoning.

• e.g.:• All sheep that I’ve seen are white• All sheep must be white

• Most scientific discoveries made using inductive reasoning

• The Raven Paradox debates the philosophical problems with this method but it is still accepted as a superior method.

Hypothetico-Deductive Thinking


1. What is inductive thinking?2. Give an example of inductive thinking

other than the one used above.3. What is deductive thinking?4. Give an example of deductive

thinking other than the one used above.

Quiz


• Data - information about natural world gathereddirectly/indirectly through senses

• Quantifiable • Greatest accuracy possible• Experimenter’s choice• Verifiable & verified

Data


• Laws - describes what nature does under certain conditions, and will predict what will happen as long as those conditions are met. (http://science.kennesaw.edu/~rmatson/3380theory.html)

• Theories - comprehensive explanation of an important feature of nature; supported by many

facts gathered over time; allow scientists to make predictions about as yet unobserved phenomena.

• Objective - all data considered• Rational - clear, logical connections between

data while forming theory• Highest level of reliability in science

Theories & Laws


Debate and revision of ideas in science is a natural process. Debate is NOT

evidence that a theory is fatally flawed.


1. What are data?2. Explain the difference between data and

information.3. Explain the difference between a law and

a theory.4. Why does the statement, “It’s just a

theory”, cause misunderstanding of science by nonscientists?

Quiz


• No rigid, lock-step series of procedures always followed by every scientist in every situation

• Many methods used to do science as long as they meet the criteria described above

• Methods used depend upon type of science done

Methods

Repeat nightly 1000x until it has become your mantra:


Theoretical - employs mathematical models and abstractions in an attempt to explain natural phenomena. Experimental – practical testing of hypotheses via controlled, natural, observational experiment


• Methods always involve the following:• Hypothetico-deductive reasoning• Careful observation of natural events• Asking questions• Forming hypotheses (testable assumptions)

• Testable, verifiable, falsifiable• Inference from observations• Remember: never proven, never right or

wrong• Data either support, fail to support, or

inconclusive• Confirmed hypotheses become points of

information within a theory.• Testing hypotheses


Careful Observation

From http://www.marinebiodiversity.ca/shark/english/derby_mako.jpg


Asking Questions

From http://i.treehugger.com/files/th_images/dropping-knowledge-d-05.jpg


• Scientists then often form a hypothesis • Possible explanation for an event or set of

observations, a testable assumption• Developed by making an inference from a

set of specific observations to reach a general conclusion

• e.g., you observe that each time you spray an ant, a bee, or a wasp, with Raid™, it dies. From these observations you infer that Raid kills all insects

• Based on repeatable observation, experience and literature research


• A hypothesis is not an educated guess.• Beginning scientists often write down their

hypothesis in "if....then" format• e.g- since cockroaches are insects, you

could write, "If I treat cockroaches with RAID™, then they will die”

• Not right or wrong; data either support or fail to support

• Can never, under any circumstances, be proven

• Must be testable and falsifiable.


1. Explain the difference between a scientific law and a scientific theory.

2. Describe a scientific hypothesis. 3. What is a control, and how many are

there in a good scientific experiment?

4. What is a control group?5. Explain the difference between

controlled, natural or quasi-, and observational studies.

Quiz


• Make predictions based on hypotheses, test the predictions

• Test these predictions through experiments• Mental, mathematical, computer model,

physical• Variables (conditions that change)

• Independent vs. dependent• Controls (conditions held constant)

• Positive & negative• Control experiment

• Control group• Experimental group• Repeatable and repeated


• Can be mental, mathematical, computer simulations, or physical procedures

• Have variables, or conditions that can change • When possible, only one condition changed,

and in specific way by the scientist • referred to as the independent variable

• Doing this increases the certainty that the observed results are caused by this variable

• When possible, changes in the dependent variable must be quantified

• Dependent variable = condition that changes as result of manipulation of independent variable

Scientific Experiments


• To be considered scientifically valid, experiments must be repeatable and repeated

• i.e.-must be possible to do the experiment over, preferably by different scientists, yielding similar results each time

• To further strengthen cause-and-effect relationship, all other variables need to be controlled.

• Good experiments contain at least one experimental group and at least one control group

• In the experimental group, the chosen variable is changed while all other conditions are held constant

• In the control group, all conditions are held constant.


• Draw conclusions based upon results• Deductive reasoning, i.e., reasoning from the

specific to the general• Communicate results to other scientists and to

public


• List the characteristics of a valid scientific experiment.

Quiz


….for now.

11/8/2015 Nature of Science. 11/8/2015 Nature of Science 1. What is science? 2. What is an observation? 3. What is a fact? 4. Define theory. 5. Define.

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