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

2. Overview Understanding What Science is, and What it isn’t
Observations, Facts, Inferences, and Hypotheses
Measurements and Uncertainty
Misunderstandings about Science and Society
Environmental Questions and the Scientific Method

3. Understanding What Science Is
Scientific understanding of life and its environment is based on scientific method
Science is a process
A way of knowing
Results in conclusions, generalizations and sometimes laws
Allows us to explain a phenomenon and make predictions (based on knowledge at the present time)

5. Science as a way of knowing
Continuous process
Sometimes a science undergoes a fundamental revolution in ideas
Science begins with observations
Example:
How many birds nest at Mono Lake?
What food do they eat?
Deals only with statements that can be disproved

6. Disprovability
A statement can be said to be scientific if someone can state a method by which it could be disproved
Many ways of looking at the world
Distinction between scientific statement and nonscientific is not a value judgment
Simply a philosophical one

9. Observations, Facts, Inferences, and Hypotheses
Made by any of the five senses or instruments that measure beyond what we sense
Inference
Generalization that arises from a set of observations
Fact
observation about a particular thing agreed by all

10. Hypothesis Type of statement used
When scientists wish to test an inference
Can be disproved
If a hypothesis has not been disproved
Is still not proven true
Only found to be probably true

11. Controlling Variables
A valid scientific experiment keeps all variables constant, except the independent and dependent variables
Controlled experiment
An exact duplicate of an experiment is compared back to a standard or control
One variable is altered (independent variable)
This may cause a change in another variable in the experiment (dependent variable)

12. Variables Dependent variable Independent variable Manipulated variable
rate of photosynthesis
Independent variable
amount of light
Manipulated variable
Ind. variable because can be changed
Responding variable
Dependent variable because it responds to change

13. Data Quantitative - numerical Qualitative - non-numerical
Ex: diameter of a tree trunk
Qualitative - non-numerical
Ex: species of tree

14. Inductive v. Deductive Reasoning
Scientific Reasoning combines both deductive and inductive reasoning
Deductive reasoning
Involves reasoning from initial definitions and assumptions
Keep in mind, science requires not only logical reasoning, but correct premises

15. Deductive reasoning
Premise: a straight line is the shortest distance between two points
Premise: The line from A to B is the shortest distance between points A and B
Conclusion: Therefore, the line from A to B is a straight line
Proof using deductive reasoning does not require that the premises be true, only that the reasoning foolproof

16. Deductive reasoning Premise: Humans are the only tool making organisms
Premise: the woodpecker finch uses tools
Conclusion: Therefore, the woodpecker finch is a human being!

17. Inductive v. Deductive reasoning
Inductive Reasoning
Generalizations based on a number of observations
Example
Breeding male grebes have golden feathers
This is only true until we observe a breeding male grebe that does not have golden feathers
Proof of inductive reasoning is stated in terms of probability of occurance

18. Measurements and Uncertainty
When we add numbers to our analysis
Obtain another dimension of understanding
Visualize relationships
Make predictions
Analyze strength of relationships

19. Models and Theory Model Many types of models
A deliberately simplified construct of nature
Many types of models
Physical working model
Pictorial model
Set of mathematical equations
Computer model

20. Measurements and Uncertainty
People generally put more faith into the accuracy of measurements than do scientists
Measurements are useless unless accompanied by an estimate of their uncertainty
Experimental error

21. Historical Evidence- Alternative to Direct Experimentation
Frequency of fires in the BWCA of MN
Three kinds of data used
Written records
Tree-ring records
Buried records (fossil and pre-fossil org deposits)
Fire scars could be seen in record

22. Historical Evidence By examining cross sections
Possible to determine the date of each fire
Number of years between fires
Heinselman determined it burned once per century
Fires shown to be integral part of forest ecology

23. Historical Evidence
Historical info meets the primary requirement of scientific method
Ability to disprove a statement
Major source of data that can be used to test hypotheses in ecology

24. Accuracy and Precision
What we know
Extent to which a measurement agrees with the accepted value
Precision
How well we measure
The degree of exactness with which the quantity was measured

25. Process of Making Decisions - Similar to Scientific Method
1. Formulate a clear statement of the issue to be decided
2. Gather the scientific information related to the issue
3. List all alternative courses of action
4. Predict the positive and negative consequences of each course of action and the probability that each consequence will occur.
5. Weigh the alternatives and choose the best solution.

26. Misunderstandings about Science
Scientific theory - grand scheme that relates and explains many observations and is supported by a great deal of evidence
In everyday usage theory may mean a guess, a hypothesis, a prediction, a notion, a belief

27. Science and Technology
Science is a search for understanding
Technology is the application of scientific knowledge that benefits humans
The two are intertwined
In our daily lives most of us do not encounter science but the products of science

28. Misunderstandings about Science
Myth of objectivity or value free science
Pseudoscientific
Untestable, lack empirical evidence or based on faulty reasoning
Frontier science
Ideas that may move into realm or science or pseudoscience

29. Environmental Questions and the Scientific Method
Environmental sciences deal with especially complex systems.
Not as neat as the scientific method
Different approach has been used in environmental sciences
Example: California Condor