Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 1 Table of Contents Section 1 What is Physics Section 2 Measurements in Experiments Section 3 The Language of Physics The Science of Physics

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What is Physics Chapter 1 Objectives Describe the processes of the scientific method. Describe the role of models and diagrams in physics. Identify activities and fields that involve the major areas within physics.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What is Physics Chapter 1 The Topics of Physics Physics is simply the study of the physical world. Your goal in Physics is to use a small number of basic concepts, equations, and assumptions to describe the physical world. This will allow you to make predictions about a broad range of phenomena.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What is Physics Chapter 1 The areas of Physics 1. Mechanics - The study of motion and its causes. –Falling objects, friction, weight, spinning objects. 2. Thermodynamics – The study of heat and temperature. –Melting and Freezing processes, engines, refrigerators. 3. Vibration and Wave Phenomena – The study of specific types of repetitive motion. –Springs, pendulums, sound

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What is Physics Chapter 1 The areas of Physics (cont) 4. Optics – The study of light. –Mirrors, lenses, color, astronomy 5. Electromagnetism – The study of electricity, magnetism, and light. –Electrical charge, circuitry, permanent magnets, electromagnets. 6. Relativity – The study of particles moving at any speed, including very high speed. –Particle collisions, particle accelerators, nuclear energy.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What is Physics Chapter 1 The areas of Physics (cont.) 7. Quantum Mechanics – The study of submicroscopic particles. –The atom and its parts

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Types of observations Qualitative- descriptive, but not true measurements –Hot –Large Quantitative- describe with numbers and units –100  C –15 meters Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What is Physics Chapter 1 The Scientific Method The scientific method is a way to ask and answer scientific questions by making observations and doing experiments. Steps of the scientific : –Observation (Ask a Question) –Collect Data (Do Background Research) –Construct a Hypothesis (Educated guess) –Test Your Hypothesis by Doing Experiments –Analyze Your Data and Draw a Conclusion The conclusion is only valid if it can be verified by other people. –Communicate Your Results

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 1 The Scientific Method Section 1 What is Physics?

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What is Physics Chapter 1 The Scientific Method (cont) System – A set of items or interactions considered a distinct physical entity for the purpose of study. –Decide what to study and eliminate everything else that has minimal or no effect on the problem. –Draw a diagram of what remains (Model) Models – A replica or description designed to show the structure or workings of an object, system, or concept. –Models help guide experimental design

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 1 The System Section 1 What is Physics?

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 1 The Scientific Model Section 1 What is Physics?

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What is Physics Chapter 1 The Scientific Method (cont) Hypothesis – A reasonable explanation for observations, one that can be tested with additional experiments. –The hypothesis must be tested in a controlled experiment. Controlled Experiment- Only one variable at a time is changed to determine what influences the phenomenon you are observing.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Measurements in Experiments Chapter 1 Objectives List basic SI units and the quantities they describe. Convert measurements into scientific notation. Distinguish between accuracy and precision. Use significant figures in measurements and calculations.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Measurements in Experiments Chapter 1 Numbers As Measurements Numerical measurements in science contain the value (number) and Dimension. Dimension is the physical quantity being measured (length, mass, time, temperature, electric current) Each dimension is measured using units and prefixes from the SI system. The dimension must match the unit. (ex. If you are measuring length, use the meter(m), not the kilogram(kg)

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Measurements in Experiments Chapter 1 SI is the standard measurement system for science. Used so that scientists can communicate with the same language. There are seven base units. They are: –Meter(m) – length –kilogram(kg) – Mass –Second(s) – Time –Kelvin(K) – Temperature –Ampere(A) – current –Mole(mol) – amount of substance –Candela(cd) – luminous intensity

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Measurements in Experiments Chapter 1 Common Metric Prefixes: -See handout or visit reference section of website -Be able to convert between any prefix and another.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How good are the measurements? Scientists use two word to describe how good the measurements are: Accuracy- how close the measurement is to the actual value. Precision- how well can the measurement be repeated.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Differences Accuracy can be true of an individual measurement or the average of several. –Problems with accuracy are due to error Precision requires several measurements before anything can be said about it. –Precision describes the limitation of the measuring instrument.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Percent Error Percent error = (Experimental Value – Accepted value) x 100 Accepted Value Percent error can be negative.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Let’s use a golf analogy

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Accurate?No Precise?Yes

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Accurate?Yes Precise?Yes

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Precise? No Accurate? Maybe?

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Accurate?Yes Precise?We cant say!

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Percent Error l Absolute value of error l I know that I weigh 150 kg. If I weigh myself and the balance says 165 kg, what is the percent error?