Introduction to Earth Science

Chapter 1, Section 1 - What Is Earth Science?                                                                                                                                                    

Earth Science - The scientific study of Earth and the universe around it.
  • Earth science is an old field of study.
    • 780 BCE - Oldest records of earthquakes (China).
    • 200 BCE - Catalog of rocks and minerals (Greece).
    • 906 CE - Mayan observatory for tracking the paths of celestial objects (Mexico).
  • Based on observation and experimentation.  (Like other sciences.)

Value of Earth Science
  • Prediction of natural disasters, and development of ways to limit damage or speed recovery.
  • Understanding of our place in the universe (astronomy) or in Earth's history (geology).
  • Locating, harvesting and use of resources.

Chapter 1, Section 2 - Science as a Process                                                                                                                                                      

Scientific Method - A standard process by which scientists ask questions, develop hypotheses, test their hypotheses, and draw conclusions.

Observation - 1. The process of obtaining information by using the senses.  2. The information obtained by using the senses.

Hypothesis - An idea or explanation that is based on observations and that can be tested.

A good hypothesis is one that can be tested with an experiment!

Experiment - A procedure carried out according to certain guidelines to test a hypothesis.
  • Variable - A factor in an experiment that can be changed.
    • Independent Variable - The factor that is deliberately changed by the person doing the experiment.
    • Dependent Variable - The factor that changes as a result of the change in the independent variable.
  • Control Group - A group in an experiment that is not changed.  (The experimental group is usually identical to the control group, except for the one variable being tested.)  It is used to provide a baseline to compare the variable to.

Scientific Measurement & Analysis

SI - The International System of Units.
  • Standard units for length, mass, temperature and volume.
  • Based on powers of 10.
  • Used worldwide.

Accuracy - How close a measurement is to the true value of the thing being measured.
Precision - The exactness of a measurement.

Error - The amount of imprecision in a set of measurements.


Model - A description, representation, or imitation of an object, system, process or concept.
  • Physical Model - A 3D model that can be touched.
  • Graphical Model - A map, chart or graph.
  • Conceptual Model - Verbal or graphical models that represent how a system works or is organized.
  • Mathematical Model - Mathematical equations that represent the way a system or process works.
  • Computer Model - Allow scientists to conduct experiments by changing variables.

Acceptance of Scientific Ideas

When a scientist reaches a conclusion...
  • Peer review - The process in which experts in a given field examine the results and conclusions of a scientist's study before that study is accepted for publication.
  • Findings are then published in scientific journals or presented at professional meetings.
Scientific Law - A general statement that describes how the natural world behaves under certain conditions and for which no exceptions have been found.

Theory -
  • The explanation for some phenomenon that is based on observation, experimentation and reasoning.
  • Supported by a large quantity of evidence.
  • Does not conflict with any existing experimental results or observations.
Both theories and scientific laws can be modified as new information is discovered.  Often, information from several branches of science is used to support a given theory.