Chapter 2 – Measurements and Calculations Section 1 – The Scientific Method

The scientific method is a logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data.

Observations Quantitative vs Qualitative

System A specific portion of matter in a given region of space that has been selected for study during an experiment or observation.

Hypotheses Scientists examine observations and data in order to find relationships and patterns Make generalizations about the behavior they have observed The generalizations are used to form a hypothesis or testable statement The hypothesis is a basis for making predictions and carrying out further experiments

Testing hypotheses Design an appropriate experiment or set of experiments to test the hypothesis. Control group Careful and accurate observations of data Is hypothesis confirmed or disproved?

If an experiment successfully confirms your hypothesis, does that mean that the hypothesis must be true?

Theories The purpose of a theory is to explain phenomena or predict behavior Broad generalization Theories can be disproven but cannot be proven

Models A model is not just a physical object, it can be visual, verbal or mathematical An explanation of how phenomena occur and how data and events are related In terms of something we’re familiar with Ex. Atomic model

Difference between a model and a theory Model – relatively simple, give a picture of a phenomena Theory – broader, more detailed explanation of behavior

So what’s a Law? Concise but general statements about how nature behaves Ex. Law of conservation of mass To be a law, must be found experimentally valid over a wide range of observed phenomena Scientific laws are descriptive