L1 U2 Lab Safety, Equipment, and Scientific Methods

Personal Protective Equipment (PPE)

the equipment that laboratory people wear and use as protection against hazardous materials

scientific method

the principles and procedures for the systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of hypotheses


a testable explanation for a set of observations based on the available data and guided by inductive reasoning and narrower in scope than a theory

null hypothesis

the hypothesis that an observed difference (as between the means of two samples) is due to chance alone and not due to a systematic cause

independant variable

a factor whose value is changed during the experiment to reveal possible effects on another factor (the dependent variable)

Dependant variable

a factor whose value is measured during an experiment to see whether it is influenced by changes in another factor (the independent variable)

control group

a set of subjects that lacks (or does not receive) the specific factor being tested

experimental group

a set of subjects that has (or receives) the specific factor being tested in a controlled experiment