The Scientific Method An overview

What is Science? “Science” derived from Latin ‘to know’ Way of asking and answering questions Seeking answers to questions about natural phenomena Reduces emotional reactions (Bias), when solving problems.

Forms of Scientific Inquiry Discovery or Descriptive Science – Observation – Qualitative vs. Quantitative data – Example: There are two red sweaters in my closet. Qualitative – descriptions - red sweaters Quantative – numbers - two (2)

Types of Logic Inductive Reasoning – Derive generalizations based on specific observations

Types of Logic Inductive Reasoning – Derive generalizations based on specific observations Deductive Reasoning - Specific predictions follow from general premise

Forms of Scientific Inquiry Discovery or Descriptive Science – Observation – Qualitative vs. Quantitative data Hypothesis-Based Science

Scientific Design Scientific knowledge begins with an observation and a proposed explanation. Explanation called a hypothesis A hypothesis is testable, measurable, and duplicatable. In science hypotheses are tested by using them to make predictions about how a particular system will behave

Scientific Method Video Video

Theories and Natural Laws Theory: a description of the world that covers a relatively large number of phenomena and has met many observational and experimental tests

Can Theories Become Laws? Theories DO NOT become laws. Theories attempt to explain laws and other phenomena. A Law is a rule or body of rules and principles governing a phenomenon, example: THE LAW OF GRAVITY, in science, laws are absolute or unquestioned. A Theory is a set of statements or principles devised to explain a group of facts or phenomena. For a given phenomenon, several theories can exist, and the results can be disputed, this is its basic difference with a law.

Scientific Method in Action We use the scientific method in everyday life Example: You got in your car to drive up here and turned the key but the car wouldn’t start (observation)

Scientific Method in Action Example: You got in your car to drive up here and turned the key but the car wouldn’t start (observation) Hypothesis: There is something wrong with the car

Scientific Method in Action Example: You got in your car to drive up here and turned the key but the car wouldn’t start (observation) Hypothesis: There is something wrong with the car Predictions: battery dead, ignition problem, out of gas

Scientific Method in Action Test predictions: turn on headlights, check spark plug wires, dip stick in gas tank

Scientific Method in Action Test predictions: turn on headlights, check spark plug wires, dip stick in gas tank Analyze results: headlights work, strong ignition spark, no gas on dip stick-gas gauge reads half full

Scientific Method in Action Test predictions: turn on headlights, check spark plug wires, dip stick in gas tank Analyze results: headlights work, strong ignition spark, no gas on dip stick-gas gauge reads half full Draw conclusion: gauge inaccurate, out of gas

Do you know the difference between the independent and dependent variables?

Independent Variable The independent, or manipulated variable, is a factor that’s intentionally varied by the experimenter. Ones you change – Manipulated Variable Graphed on the x-axis John is going to use 25g., 50g., 100g., 250g., 500g. of sugar in his experiment.

Dependent Variable The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable. Ones you measure – responding variable Graphed on the y-axis In this case, it would be the size of the loaf of bread.

Control Group In a scientific experiment, the control is the group that serves as the standard of comparison. The control group is exposed to the same conditions as the experimental group, except for the variable being tested. All experiments should have a control group.

experimental group: group(s) subjected to the independent variable. (Manipulated variable) reproducibility: producing the same result consistently to verify result. It is therefore important to describe your experimental design in enough detail for others to perform the same experiment.