Bell Ringer Express your perceptions and attitude about physics on a sheet of paper. Do you feel it is necessary to learn? List your planned career and if and how physics will contribute to your career.

Bell Ringer What is the goal of physics? Using the letters for physics, come up with seven adjectives which describe how you feel about it. P – H – Y – S – I – C –

Chapter 1: The Science of Physics Coach Kelsoe Physics Pages 3–37

Section 1–1: What is Physics? Coach Kelsoe Physics Pages 4–9

Objectives Identify activities and fields that involve the major areas within physics. Describe the processes of the scientific method. Describe the role of models and diagrams in physics.

The Branches of Physics

The Topics of Physics Many people believe physics to be a difficult science that isn’t relevant to their lives, but everything around you can be described using the tools of physics. The goal of physics is to use a small number of basic concepts, equations, and assumptions to describe the physical world.

Physics is Everywhere These physics principles can then be used to make predictions about a broad range of phenomena. Physics discoveries often turn out to have unexpected practical applications, and advances in technology can in turn lead to new physics discoveries. You see physics at work every single day – in any problem that deals with temperature, size, motion, position, shape, or color.

Physics and Technology

The Scientific Method There is no single procedure that scientists follow in their work, but there are certain steps common to all good scientific investigations. These steps are collectively called the scientific method. We normally recognize the scientific method as a step-by-step process, but many times it is hard to separate the steps.

Scientific Method: CSI Style Let’s investigate a car accident with the stages of the scientific method. Observation/collection of data: The investigator examines the crime scene and fills out a report. Hypotheses: The investigator imagines several likely scenarios that might have caused the accident. Maybe the driver was intoxicated, fell asleep, or was speeding; maybe the car had mechanical failure; maybe weather conditions affected the car’s traction or the driver’s ability to see the road well.

Scientific Method: CSI Style Let’s investigate a car accident with the stages of the scientific method. Experiments/Tests: The investigator might order a blood-alcohol-level test, check the car parts, test-drive the car in different weather conditions, or try to reproduce the skid marks left by the car. Interpret/Revise Hypothesis: The investigator must reexamine evidence and possibly revise his hypothesis. The evidence may be inconclusive. Conclusions: The investigator goes to court, reexamines the evidence, and defends his theory of how the accident occurred.

Models Physics uses models that describe phenomena. A model is a pattern, plan, representation, or description designed to show the structure or workings of an object, system, or concept. A set of particles or interacting components considered to be a distinct physical entity for the purpose of study is called a system.

Hypotheses Models help scientists develop hypotheses. A hypothesis is an explanation that is based on prior scientific research or observations and that can be tested. The process of simplifying and modeling a situation can help you determine the relevant variables and identify a hypothesis for testing.

Hypotheses Galileo modeled the behavior of falling objects in order to develop a hypothesis about how objects fall. If heavier objects fell faster than lighter ones, would two bricks of different masses tied together fall slower (b) or faster (c) than the heavy brick alone (a)? Because of this contradiction, Galileo hypothesized instead that all objects fall at the same rate, as in (d).

Controlled Experiments A hypothesis must be tested in a controlled experiment. A controlled experiment tests only one factor at a time by using a comparison of a control group with an experimental group.

Vocabulary Model System Hypothesis Controlled Experiment