THE NATURE OF SCIENCE

The Method of Science

Science – process that uses observation and investigation to gain knowledge about events in nature

Scientific Method An organized set of investigation procedures used by scientists

Hypothesis – educated guess or testable prediction Experiment – organized procedure for testing hypothesis Control – standard for comparison Constant – factor that doesn’t vary in experiment Independent variable – factor that is adjusted by the experimenter (x-axis) Dependent variable – factor whose value depends on the independent variable (y-axis)

Scientific Law vs. Scientific Theory Rule of nature that sums up related observations to describe a pattern in nature Ex. Law of Gravity Explanation based on experiments – most logical explanation Ex. Black Hole Theory

STANDARDS OF MEASUREMENT

International System of Units (SI) Standard system of measurement used worldwide SI Base Units Quantity Measured Unit Symbol Length meter m Mass gram g Time second s Electric current ampere A Temperature kelvin K Amt of Substance mole mol Intensity of light candela cd

– Distance between two points Volume Common SI Prefixes Prefix Symbol Multiplying Factor kilo k 1.000 deci d 0.1 centi c 0.01 milli m 0.001 micro μ 0.000 001 nano n 0.000 000 001 Length – Distance between two points Volume – The amount of space occupied by an object Mass – Amount of matter in an object Density – Mass per unit volume of a material Time – Interval between two occurring events

GRAPHING

Graph A visual display of information or data.

Line Graph Show trends or how the data changes over time

Bar Graph Useful for comparing information collected by counting

Circle Graph (pie chart) Used to show how a fixed quantity is broken down into parts