SCIENTIFIC METHOD NATURE OF SCIENCE AND EXPERIMENTAL DESIGN VANCE

SCIENCE PROCESSES What is SCIENCE?! A body of knowledge and an organized method used to gain knowledge about the observable universe. All the different sciences use rational thinking and experimentation to study the observable natural world In general the following steps are involved in scientific investigations:

SCIENCE PROCESSES 1.Recognize a question or problem 2.Make an educated guess, HYPOTHESIS, to answer the question Predict consequences that can be observed if the hypothesis is correct. The consequences should be absent if the hypothesis is not supported 3.Do an experiment to test the hypothesis and see if the predicted consequences are present 4.Interpret and analyze the results of your experiment 5.Report your conclusions

A well-tested hypothesis that is repeatedly supported by evidence may become a law or principle Scientists communicate data through peer-reviewed journals and other scientific publications Scientific facts that are observed and agreed upon by many individuals combined with well-tested hypothesis may become theories Scientists use tools and their senses to make observations

THE NATURE OF SCIENCE A scientific fact is something that can be observed and agreed upon by many individuals Scientific facts combined with well-tested hypotheses evolve into scientific theories Note that in every day common usage, the word “theory” has the same meaning as the word “hypothesis” However, this differs greatly in scientific usage as a theory has been tested and supported by data, while a hypothesis has not yet been tested When a hypothesis has been tested repeatedly, over and over, and it is ALWAYS supported by evidence, it may become known as a law or principle

THE NATURE OF SCIENCE Theories: Foundation of sciences Can always change when new evidence presents itself to the scientific community Example: Theory of Evolution There is plenty of evidence that evolution is a fact but the overarching theories about evolution, the way we think all the facts go together, might change as new observations of evolution are made Thus, science is an ever-growing body of knowledge about the observable, natural world.

THE NATURE OF SCIENCE Laws: Are statements of fact meant to describe an action Are generally accepted to be true and universal Example: Newton’s Laws of Motion Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. Scientists must communicate to share resources and knowledge. The best source for scientific information is peer-reviewed scientific journal articles

SCIENTIFIC PROCESSES There are several terms associated with scientific procedures and experimentation: Data is information collected by observations Observations are acts of viewing or noting a fact or occurrence in order to gain information An inference is a logical interpretation of data based on prior knowledge or experience

TYPES OF DATA Qualitative data is based on observable characteristics of things or events that can be collected using the five senses Example: “The juice tastes sweet to me.” Quantitative data is based on measurable characteristics of things or events such as mass, volume, length, quantity Example: “There is one liter of juice in the carton”

SCIENTIFIC PROCESSES A hypothesis is a testable explanation for observations and questions about the natural world. A variable is any factor that can affect the outcome of an experiment A dependent variable is the factor that responds to changes in other variables in an experiment; DEPENDS on independent variable An independent variable is the factor that can be changed or manipulated in an experiment by the scientist; I change the variable

SCIENTIFIC PROCESSES The experimental group is the group that is changed or manipulated in an experiment The control group is the group or subject that is used as a standard for comparison in an experiment A constant is any variable that remains the same for both the experimental and control groups.

SCIENTIFIC PROCESSES Validity is a measurement of how fair or accurate the experiment tests the hypothesis Reliability is a measurement of how consistent and trustworthy the data is