Chapter 2: Science as a Way of Knowing: Critical Thinking About the Environment.

Chapter 2:Chapter 2:Science as a Way of Knowing: Science as a Way of Knowing: Critical Thinking About the Critical Thinking About the EnvironmentEnvironment

OverviewOverview

Understanding What Science is, Understanding What Science is, and What it isn’tand What it isn’t

Observations, Facts, Observations, Facts, Inferences, and HypothesesInferences, and Hypotheses

Measurements and UncertaintyMeasurements and Uncertainty Misunderstandings about Science Misunderstandings about Science and Societyand Society

Environmental Questions and the Environmental Questions and the Scientific MethodScientific Method

Understanding What Understanding What Science IsScience Is Scientific understanding of life Scientific understanding of life and its environment is based on and its environment is based on scientific methodscientific method

Science is a processScience is a process A way of knowingA way of knowing Results in conclusions, Results in conclusions, generalizations and sometimes lawsgeneralizations and sometimes laws

Allows us to explain a phenomenon Allows us to explain a phenomenon and make predictions (based on and make predictions (based on knowledge at the present time)knowledge at the present time)

Science as a way of Science as a way of knowingknowing Continuous processContinuous process

Sometimes a science undergoes a Sometimes a science undergoes a fundamental revolution in ideasfundamental revolution in ideas

Science begins with observationsScience begins with observations Example: Example:

How many birds nest at Mono Lake?How many birds nest at Mono Lake? What food do they eat?What food do they eat?

Deals only with statements that Deals only with statements that can be disprovedcan be disproved

DisprovabilityDisprovability

A statement can be said to be A statement can be said to be scientific if someone can state a scientific if someone can state a method by which it could be method by which it could be disproveddisproved

Many ways of looking at the worldMany ways of looking at the world Distinction between scientific Distinction between scientific statement and nonscientific is not a statement and nonscientific is not a value judgmentvalue judgment

Simply a philosophical oneSimply a philosophical one

Observations, Facts, Observations, Facts, Inferences, and Inferences, and HypothesesHypotheses ObservationsObservations

Made by any of the five senses or Made by any of the five senses or instruments that measure beyond instruments that measure beyond what we sensewhat we sense

InferenceInference Generalization that arises from a Generalization that arises from a set of observationsset of observations

FactFact observation about a particular observation about a particular thing agreed by allthing agreed by all

HypothesisHypothesis

Type of statement usedType of statement used When scientists wish to test an When scientists wish to test an inferenceinference

Can be disprovedCan be disproved If a hypothesis has not been If a hypothesis has not been disproveddisproved Is still not proven trueIs still not proven true Only found to be probably trueOnly found to be probably true

Controlling VariablesControlling Variables

A valid scientific experiment keeps A valid scientific experiment keeps all variables constant, except the all variables constant, except the independent and dependent variablesindependent and dependent variables

Controlled experimentControlled experiment An exact duplicate of an experiment is An exact duplicate of an experiment is compared back to a standard or controlcompared back to a standard or control

One variable is altered (independent One variable is altered (independent variable)variable)

This may cause a change in another variable This may cause a change in another variable in the experiment (dependent variable)in the experiment (dependent variable)

VariablesVariables

Dependent variableDependent variable rate of photosynthesisrate of photosynthesis

Independent variableIndependent variable amount of lightamount of light

Manipulated variableManipulated variable Ind. variable because Ind. variable because can be changedcan be changed

Responding variableResponding variable Dependent variable Dependent variable because it responds to because it responds to changechange

DataData

Quantitative - numericalQuantitative - numerical Ex: diameter of a tree trunkEx: diameter of a tree trunk

Qualitative - non-numericalQualitative - non-numerical Ex: species of treeEx: species of tree

Inductive v. Deductive Inductive v. Deductive ReasoningReasoning

Scientific Reasoning combines Scientific Reasoning combines both deductive and inductive both deductive and inductive reasoningreasoning

Deductive reasoningDeductive reasoning Involves reasoning from initial Involves reasoning from initial definitions and assumptionsdefinitions and assumptions

Keep in mind, science requires not Keep in mind, science requires not only logical reasoning, but correct only logical reasoning, but correct premisespremises

Deductive reasoningDeductive reasoning

Premise: a straight line is the Premise: a straight line is the shortest distance between two pointsshortest distance between two points

Premise: The line from A to B is the Premise: The line from A to B is the shortest distance between points A and shortest distance between points A and BB

Conclusion: Therefore, the line from A Conclusion: Therefore, the line from A to B is a straight lineto B is a straight line

Proof using deductive reasoning does Proof using deductive reasoning does not require that the premises be true, not require that the premises be true, only that the reasoning foolproofonly that the reasoning foolproof

Deductive reasoningDeductive reasoning

Premise: Humans Premise: Humans are the only tool are the only tool making organismsmaking organisms

Premise: the Premise: the woodpecker finch woodpecker finch uses toolsuses tools

Conclusion: Conclusion: Therefore, the Therefore, the woodpecker finch woodpecker finch is a human being!is a human being!

Inductive v. Deductive Inductive v. Deductive reasoningreasoning

Inductive ReasoningInductive Reasoning Generalizations based on Generalizations based on a number of observationsa number of observations

ExampleExample Breeding male grebes have Breeding male grebes have golden feathersgolden feathers

This is only true until This is only true until we observe a breeding we observe a breeding male grebe that does not male grebe that does not have golden feathershave golden feathers

Proof of inductive Proof of inductive reasoning is stated in reasoning is stated in terms of probability of terms of probability of occuranceoccurance

Measurements and Measurements and UncertaintyUncertainty When we add numbers to our When we add numbers to our analysisanalysis Obtain another dimension of Obtain another dimension of understandingunderstanding

Visualize relationshipsVisualize relationships Make predictionsMake predictions Analyze strength of relationshipsAnalyze strength of relationships

Models and TheoryModels and Theory

ModelModel A deliberately A deliberately simplified construct simplified construct of natureof nature

Many types of modelsMany types of models Physical working modelPhysical working model Pictorial modelPictorial model Set of mathematical Set of mathematical equationsequations

Computer modelComputer model

Measurements and Measurements and UncertaintyUncertainty People generally put more faith People generally put more faith into the accuracy of into the accuracy of measurements than do scientistsmeasurements than do scientists

Measurements are useless unless Measurements are useless unless accompanied by an estimate of accompanied by an estimate of their uncertaintytheir uncertainty Experimental errorExperimental error

Historical Evidence- Historical Evidence- Alternative to Direct Alternative to Direct ExperimentationExperimentation Frequency of fires in the BWCA of Frequency of fires in the BWCA of MNMN

Three kinds of data usedThree kinds of data used Written recordsWritten records Tree-ring recordsTree-ring records Buried records (fossil and pre-fossil Buried records (fossil and pre-fossil org deposits)org deposits)

Fire scars could be seen in recordFire scars could be seen in record

Historical EvidenceHistorical Evidence By examining cross By examining cross sectionssections Possible to determine Possible to determine the date of each firethe date of each fire

Number of years Number of years between firesbetween fires

Heinselman Heinselman determined it determined it burned once per burned once per centurycentury

Fires shown to be Fires shown to be integral part of integral part of forest ecologyforest ecology

Historical EvidenceHistorical Evidence

Historical info meets the Historical info meets the primary requirement of primary requirement of scientific methodscientific method Ability to disprove a statementAbility to disprove a statement

Major source of data that can Major source of data that can be used to test hypotheses in be used to test hypotheses in ecologyecology

Accuracy and PrecisionAccuracy and Precision

Accuracy Accuracy What we knowWhat we know Extent to which a measurement Extent to which a measurement agrees with the accepted valueagrees with the accepted value

Precision Precision How well we measureHow well we measure The degree of exactness with which The degree of exactness with which the quantity was measuredthe quantity was measured

Process of Making Process of Making Decisions - Similar to Decisions - Similar to Scientific MethodScientific Method1. Formulate a clear statement of the 1. Formulate a clear statement of the issue to be decidedissue to be decided

2. Gather the scientific information 2. Gather the scientific information related to the issuerelated to the issue

3. List all alternative courses of action3. List all alternative courses of action4. Predict the positive and negative 4. Predict the positive and negative consequences of each course of action consequences of each course of action and the probability that each and the probability that each consequence will occur.consequence will occur.

5. Weigh the alternatives and choose the 5. Weigh the alternatives and choose the best solution.best solution.

Misunderstandings about Misunderstandings about ScienceScience Scientific theory - grand Scientific theory - grand scheme that relates and scheme that relates and explains many observations and explains many observations and is supported by a great deal of is supported by a great deal of evidenceevidence

In everyday usage theory may In everyday usage theory may mean a guess, a hypothesis, a mean a guess, a hypothesis, a prediction, a notion, a beliefprediction, a notion, a belief

Science and TechnologyScience and Technology

Science is a search for Science is a search for understandingunderstanding

Technology is the application of Technology is the application of scientific knowledge that benefits scientific knowledge that benefits humanshumans

The two are intertwinedThe two are intertwined In our daily lives most of us do In our daily lives most of us do not encounter science but the not encounter science but the products of scienceproducts of science

Misunderstandings about Misunderstandings about ScienceScience

Myth of objectivity Myth of objectivity or value free or value free sciencescience

PseudoscientificPseudoscientific Untestable, lack Untestable, lack empirical evidence or empirical evidence or based on faulty based on faulty reasoningreasoning

Frontier scienceFrontier science Ideas that may move Ideas that may move into realm or science into realm or science or pseudoscienceor pseudoscience

Environmental Questions Environmental Questions and the Scientific and the Scientific MethodMethod Environmental sciences deal with Environmental sciences deal with especially complex systems.especially complex systems. Not as neat as the scientific Not as neat as the scientific methodmethod

Different approach has been used Different approach has been used in environmental sciencesin environmental sciences Example: California CondorExample: California Condor