Chapter 2: The Scientific Method and Environmental Sciences

Understanding What Science Is• Scientific understanding of life and its

environment is based on scientific method.• Science is a process, a way of knowing:

– It results in conclusions, generalizations, scientific theories and even scientific laws/facts

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

Science as a way of knowing

• Continuous process– Sometimes a science undergoes a fundamental

revolution in ideas

• Science begins with observations– E.g. How many birds nest at Mono Lake?– What food do they eat?

• Deals only with statements that can be disproved.

Assumptions of Science

• Events in the natural world follow patterns.• Basic patterns and rules are the same

throughout the universe.• Based on a type of reasoning known as

induction.• Generalizations can be tested and disproved.• New evidence can disprove existing

scientific theories, but can never provide absolute proof.

Deductive reasoning - reasoning from the general to the particular (or from cause to effect)

• Example 1– 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.

Inductive reasoning - reasoning from detailed facts to general principlesGeneralizations based on a number of observations = inductive reasoning.

Probability

• A way of expressing our certainty– Our estimation of how good our observations are– How confident we are of our predictions

• Scientific reasoning combines induction and deduction

Measurements and Uncertainty

• Measurements are limited– Meaningless unless it is accompanied by an

estimate of its uncertainty.

• Two sources of uncertainty– Real variability in nature– Every measurement has some error– Called experimental error

Accuracy and Precision

• Accuracy refers to what we know.

• Precision refers to how well we measure.

Observations, Facts, Inferences, and Hypotheses

• Observations - may be made by any of the five senses or instruments that measure beyond what we sense.

• Inference - a generalization that arises from a set of observations.

• Fact – observations about a particular thing agreed by all

Scientific Method1. Make observation and develop a question about the observations.

2. Develop a tentative answer- a hypothesis.

3. Design a controlled experiment to test the hypothesis.

4. Collect data.

5. Interpret data.6. Draw a conclusion from the data.7. Compare the conclusion to the hypothesis and determine whether the results support

or reject the hypothesis.8. If the hypothesis is supported, conduct additional experiments to test it further. If the

hypothesis is rejected, construct a new hypothesis.

Scientific Method

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.

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.

Environmental Questions and the Scientific Method

• Environmental sciences deal w/ especially complex systems.– Not as neat as the scientific method.

• Different approach has been used in environmental sciences.

Modern Catastrophes and Disturbances as Experiments

• Eruption of Mount St Helens in 1980– Allowed for study of dynamics of ecological

systems

• 1988 Wildfire in Yellowstone NP– Carefully monitored before and after.

Learning about Science

• Open-ended process

• Students often perceive science as a body of facts to be memorized.

• Really a set of currently accepted truths, always subject to change.