The Nature of ScienceThe Nature of Science

Questions for ConsiderationQuestions for Consideration

How do scientists solve problems?How do scientists solve problems?What are some aspects of a scientific What are some aspects of a scientific

experiment?experiment?What is the difference between a What is the difference between a

scientific law, a hypothesis, and a scientific law, a hypothesis, and a theory?theory?

What is the importance of scientific What is the importance of scientific literacy?literacy?

How Do Scientists Solve How Do Scientists Solve Problems?Problems?

The myth of “the scientific method”.The myth of “the scientific method”.Not just one method for problem-Not just one method for problem-

solving.solving.““Scientific method” often taught in Scientific method” often taught in

school is a simplified procedure for school is a simplified procedure for building knowledge.building knowledge.Real science can be much more exciting and Real science can be much more exciting and

complex.complex.No specified order for building knowledge.No specified order for building knowledge.

How Do Scientists Solve How Do Scientists Solve Problems?Problems?

Online Homework Assignment:Online Homework Assignment:Visit the following site:Visit the following site:

http://www.undsci.berkeley.eduhttp://www.undsci.berkeley.eduAnswer the questions on the worksheet Answer the questions on the worksheet

you have been given.you have been given.Due Friday, January 30, 2009.Due Friday, January 30, 2009.

For a copy of the worksheet, click below:For a copy of the worksheet, click below:

Microsoft Word Document

What Are Some Aspects of a What Are Some Aspects of a Scientific Experiment?Scientific Experiment?

Variables – factors that can change.Variables – factors that can change.Manipulated variable – changed by the Manipulated variable – changed by the

experimenter.experimenter.““Independent variable”Independent variable”

Responding variable – observed by the Responding variable – observed by the experimenter.experimenter.““Dependent variable”Dependent variable”

ControlControlVariables that are kept constant.Variables that are kept constant.Ensures that the impact of another Ensures that the impact of another

factor can be better understood.factor can be better understood.

ExampleExample

A contract research organization (CRO) is A contract research organization (CRO) is being paid to find out if a new drug for being paid to find out if a new drug for tuberculosis yields better results than the tuberculosis yields better results than the standard treatment.standard treatment.

They organize a double-blind study:They organize a double-blind study: One group of patients is given the new drug.One group of patients is given the new drug. One group of patients is given a placebo.One group of patients is given a placebo.

Placebo: A “sham” therapy that does not actually Placebo: A “sham” therapy that does not actually contain any sort of medication.contain any sort of medication.

Both groups’ progress is compared to the Both groups’ progress is compared to the progress of patients who receive the standard progress of patients who receive the standard therapy.therapy.

ExampleExample In the clinical study, what is the CRO In the clinical study, what is the CRO

attempting to find out?attempting to find out?If the new TB drug is more effective than If the new TB drug is more effective than

the standard treatment.the standard treatment.What is the control group?What is the control group?

The placebo group is the control group.The placebo group is the control group.What is the responding variable?What is the responding variable?

The health of the group that receives The health of the group that receives the drug (compared to the health of the the drug (compared to the health of the group that receives the standard group that receives the standard treatment). treatment).

Fact, Hypothesis, Law, TheoryFact, Hypothesis, Law, Theory

FactFact An observation.An observation.

HypothesisHypothesis A proposed explanation for observations.A proposed explanation for observations. Can be supported or refuted by further testing.Can be supported or refuted by further testing.

LawLaw A concise statement that describes a A concise statement that describes a

relationship in nature.relationship in nature. TheoryTheory

A broadly supported explanation for a set of A broadly supported explanation for a set of observed phenomena.observed phenomena.

Theories CANNOT be 100% proven.Theories CANNOT be 100% proven. They are generally accepted as true unless They are generally accepted as true unless

disproven.disproven.

The Nature of ScienceThe Nature of Science

Science:Science:is tentative.is tentative.doe NOT follow a single method.doe NOT follow a single method.is goal-oriented.is goal-oriented.uses laws to describe and theories to uses laws to describe and theories to

explain.explain.is creative.is creative.

The Tunguska EventThe Tunguska Event

On June 30, 1908 there was a large On June 30, 1908 there was a large explosion above the Tunguska region explosion above the Tunguska region in Russia.in Russia.At about 7:17 am local time, At about 7:17 am local time,

eyewitnesses near Lake Baikal in Russia eyewitnesses near Lake Baikal in Russia reported seeing a column of intense blue reported seeing a column of intense blue light moving across the sky.light moving across the sky.

A few minutes later, they saw a bright A few minutes later, they saw a bright flash of light and heard loud bangs, like flash of light and heard loud bangs, like artillery fire.artillery fire.

The Tunguska EventThe Tunguska Event

Witnesses closer to the explosion were Witnesses closer to the explosion were knocked off their feet by the shockwave.knocked off their feet by the shockwave. They reported intense heat and pressure from They reported intense heat and pressure from

the blast.the blast. Windows were broken hundreds of kilometers Windows were broken hundreds of kilometers

from the blast site.from the blast site. Tremors from the explosion were registered at Tremors from the explosion were registered at

seismic stations all across Europe and Asia.seismic stations all across Europe and Asia. The explosion is thought to have been The explosion is thought to have been

equivalent to 10 – 15 Megatons of TNT, or equivalent to 10 – 15 Megatons of TNT, or about 1000 Hiroshima A-bombs.about 1000 Hiroshima A-bombs. It is also thought that the explosion happened It is also thought that the explosion happened

about 5 – 10 kilometers above the Earth’s about 5 – 10 kilometers above the Earth’s surface.surface.

The Tunguska EventThe Tunguska Event

The Tunguska EventThe Tunguska Event

What caused the Tunguska event?What caused the Tunguska event? There have been many proposed explanations, There have been many proposed explanations,

or hypotheses:or hypotheses:An alien spaceship exploded high above the Earth.An alien spaceship exploded high above the Earth.A small black hole hit the Earth.A small black hole hit the Earth.An asteroid or comet entered Earth’s atmosphere and An asteroid or comet entered Earth’s atmosphere and

exploded.exploded.A top-secret superweapon was being tested or A top-secret superweapon was being tested or

deployed by the US or Russia.deployed by the US or Russia.A chunk of antimatter entered Earth’s atmosphere A chunk of antimatter entered Earth’s atmosphere

and self-destructed when it contacted normal matter.and self-destructed when it contacted normal matter.A huge amount of natural gas was released from the A huge amount of natural gas was released from the

Earth’s crust and exploded in the air.Earth’s crust and exploded in the air.

The Tunguska EventThe Tunguska Event Scientists actively debate various Scientists actively debate various

hypotheses and attempt to use available hypotheses and attempt to use available evidence to develop a theory.evidence to develop a theory. The current theory: a comet or asteroid exploded The current theory: a comet or asteroid exploded

in the lower atmosphere.in the lower atmosphere. Supporting evidence:Supporting evidence:

Asteroids and comets Asteroids and comets dodo exist. exist. Particles from outer space enter Earth’s Particles from outer space enter Earth’s

atmosphere every day.atmosphere every day. When they do, they burn up or explode because When they do, they burn up or explode because

of the heat generated by the compressed air in of the heat generated by the compressed air in front of them.front of them.

The Tunguska EventThe Tunguska Event

Supporting evidence:Supporting evidence: A larger object (a few tens of meters across) A larger object (a few tens of meters across)

would release energy consistent with the would release energy consistent with the Tunguska blast.Tunguska blast.

Fragments found embedded in downed trees Fragments found embedded in downed trees are consistent with asteroid and comet are consistent with asteroid and comet composition.composition.

Eyewitness reports are consistent with an Eyewitness reports are consistent with an asteroid or comet impact.asteroid or comet impact.

Also, the asteroid/comet impact hypothesis Also, the asteroid/comet impact hypothesis is is parsimonius.parsimonius. it doesn’t require the existence of things that it doesn’t require the existence of things that

must be assumed without evidence, like alien must be assumed without evidence, like alien spaceships or secret superweapons.spaceships or secret superweapons.

The Importance of Scientific The Importance of Scientific LiteracyLiteracy

You are going to see ten true-false You are going to see ten true-false statements that will test your statements that will test your scientific literacy.scientific literacy.Try to determine whether each Try to determine whether each

statement is true or false.statement is true or false.

The StatementsThe Statements 1.1. Science only produces tentative conclusions that Science only produces tentative conclusions that

can can change.change. 2.2. Science has one uniform way of conducting Science has one uniform way of conducting

research research called “the scientific method”.called “the scientific method”. 3.3. When being scientific one can have faith only in When being scientific one can have faith only in

what is what is justified by empirical evidence.justified by empirical evidence. 4.4. To be scientific one must conduct experiments.To be scientific one must conduct experiments. 5. 5. An experiment can prove a theory true.An experiment can prove a theory true. 6.6. Scientific theories are just ideas about how Scientific theories are just ideas about how

something works.something works. 7.7. An accepted scientific theory is a hypothesis that An accepted scientific theory is a hypothesis that

has has been confirmed by considerable evidence and has been confirmed by considerable evidence and has endured all attempts to disprove it.endured all attempts to disprove it.

8.8. Scientists construct theories to guide further Scientists construct theories to guide further research.research.

9.9. Scientists work alone without sharing data or Scientists work alone without sharing data or ideas.ideas.

10.10. Imagination and creativity are used in all stages of Imagination and creativity are used in all stages of scientific investigations.scientific investigations.

TRUE

False

TRUE

false

false

false

TRUE

TRUE

false

TRUE

What Is The Importance of What Is The Importance of Scientific Literacy?Scientific Literacy?

Scientific literacy makes you an Scientific literacy makes you an informed person:informed person:It helps you make decisions in elections.It helps you make decisions in elections.It keeps you from being fooled by It keeps you from being fooled by

people who make fraudulent claims.people who make fraudulent claims.It keeps you from being worried about It keeps you from being worried about

things you don’t really have to worry things you don’t really have to worry about.about.

What Is The Importance of What Is The Importance of Scientific Literacy?Scientific Literacy?

If somebody tells you that the world is If somebody tells you that the world is going to end in 2012, be skeptical.going to end in 2012, be skeptical.

If somebody tells you that vaccines If somebody tells you that vaccines cause autism in children, ask for cause autism in children, ask for evidence.evidence.

If somebody tells you that the Large If somebody tells you that the Large Hadron Collider will destroy the world, Hadron Collider will destroy the world, consult a real scientist to find out.consult a real scientist to find out.

Examine the evidence for yourself and Examine the evidence for yourself and make your own informed decisions.make your own informed decisions.

SkepticismSkepticism

The truth is out there...but so is this garbage.