1. ENVIRONMENTAL SCIENCE Chapter 2 Tools of Environmental Science 2.1 Scientific Methods

2. 2.1 Scientific Methods Objectives List and describe the steps of the experimental method. Describe why a good hypothesis is not simply a guess. Describe the two essential parts of a good experiment. Describe how scientists study subjects in which experiments are not possible. Explain the importance of curiosity and imagination in science.

3. The Experimental Method The experimental (scientific) method consists of a series of steps used universally by scientists to answer questions or solve problems. Almost every scientific investigation begins with observation. Scientists use their senses to gather information about some phenomenon which captures their attention Scientists can extend their observations with a variety of tools such as microscopes, rulers, photos, etc.

4. The Experimental Method After observing something in nature, the investigator may wish to research the topic. If a question/problem remains unanswered/unsolved after researching the topic, the investigator will form a hypothesis. A hypothesis is a testable, educated guess intended to answer a question or solve a problem in the natural world. A good hypothesis should make logical sense and follow from what is currently known from the situation.

5. The Experimental Method To test their hypothesis, scientists often make predictions about what will happen if the hypothesis stated is correct. An experiment is a procedure designed to test a hypothesis under controlled conditions. Experiments should be designed to pin-point cause-and-effect relationships. When conducting an experiment, it is important that only one variable be tested at a time and a control is established.

6. The Experimental Method A variable is any part of the experiment that could change. An experimental variable is the part of the experiment that is changed. The variable being tested is the only difference between the two groups of an experiment. The group that receives the experimental treatment is the experimental group and the control group is the one that does not receive the experimental treatment.

7. The Experimental Method It is important that records of the experiment be both accurate and consistent. Any measurements, observations, or information collected is referred to as data. Organizing data into graphs, tables, and charts often help scientists to understand what the data mean. After analysis of the data, the outcome is compared to the prediction.

8. The Experimental Method The data will either support or refute the hypothesis stated. A conclusion is drawn, sometimes after repeating an experiment many times. All experiments conducted must be replicable. Scientists communicate their results in a number of ways. Professional journals News conference Professional conventions/meetings Books

10. The Correlation Method Many questions cannot be studied experimentally. Scientists often examine correlations (reliable associations between two or more events) to answer questions that are impossible or unethical to use direct experiments to solve. Though useful, correlation studies do not necessarily prove cause-and-effect relationships.

11. Scientific Habits Though there is much flexibility in science, scientists usually share some characteristics. Curiosity Skepticism Open-mindedness Honesty Creativity

12. References Scientific Method - http://is.asu.edu/plb108/course/scime th/page4.html http://is.asu.edu/plb108/course/scime th/page4.html