Chapter 1: The Science of Physics Mr. Dunk Pre-AP Physics Pearland High School

What is physics? physics is the study of the physical world physics is everywhere; any problem that deals with temperature, size, motion, position, shape, or color involves physics

Areas Within Physics NameSubjects mechanicsmotion and its causes thermodynamicsheat and temperature vibrations and wavesspecific types of repetitive motion opticslight electromagnetismelectricity, magnetism, and light

Areas Within Physics NameSubjects RelativityParticles moving at any speed, including very high speed Quantum mechanicsBehavior of submicroscopic atomic particles

What is physics? scientific method – an organized process used to conduct scientific investigations or experiments; there is no single procedure, but the following general steps are always included:

The Scientific Method make observations and collect data that lead to a question formulate and objectively test hypothesis by experimentation interpret results and revise the hypothesis and experiment if necessary state conclusions in a form that can be evaluated by others

The Scientific Method model – a replica or description designed to show the structure or workings of an object, system, or concept system – a set of items or interactions considered a distinct physical entity for the purpose of study; usually, this involves a single object and the items that immediately affect it

The Scientific Method using models can help to build hypotheses a plan or model for investigation or experimentation controlled experiment – an experiment involving the manipulation of a single variable or factor

Measurement in Experiments SI Base Units of Measurements unitsymbol lengthmeterm timesecondsec or s masskilogramkg currentampereA temperaturekelvinK

Measurement in Experiments SI Base Units of Measurements unitsymbol luminous intensity candelacd amount of a substance molemol all other units are called derived units because they are based on combinations of two or more of the SI base units

Measurement in Experiments Common Numerical Prefixes atto-a10 1 deka-da femto-f10 3 kilo-k pico-p10 6 mega-M nano-n10 9 giga-G micro-µ10 12 tera-T milli-m10 15 peta-P centi-c10 18 exa-E deci-d

Measurement in Experiments dimensional analysis is an important skill in physics since you will have to convert back and forth among various units INCLUDE UNITS IN ALL OF YOUR CALCULATIONS ! ! ! ! ! ! ! ! ! ! !

Accuracy and Precision accuracy – how close a measured value is to the true or accepted value of the quantity being measured precision – the degree of exactness with which a measurement is made and stated; reproducibility of results; can relate to the ability of an instrument to produce consistently accurate measurements

Significant Figures or Digits those digits in a measurement that are known with certainty plus the first digit that is uncertain also called sig figs or sig digs

Rules for Significant Figures all non-zero digits are significant zeros between non-zero digits are significant zeros in front of non-zero digits are not significant (they are place holders) zeros that are at the end of a number AND also to the right of the decimal are significant

Rules for Significant Figures zeros at the end of a number but to the left of the decimal are not considered significant but are important as place- holders (unless you are told that they are measured)

Rules for Significant Figures ,000

Rules for Rounding leave the number alone when the digit following the last significant figure is 0, 1, 2, 3, or 4 round up when the digit following the last significant figure is 5, 6, 7, 8, or 9

Special Rules for Rounding The Symmetric Rounding Rule This rule is sometimes followed when the digit following the last significant figure is 5. This rule says to round to the nearest even number. This rule is often used to reduce average error due to rounding since the numbers are sometimes rounded up and sometimes rounded down.

Rules for Significant Figures – Adding and Subtracting when adding or subtracting: the final answer should have the same number of digits to the right of the decimal as the measurement with the least number of digits to the right of the decimal

Rules for Significant Figures – Adding and Subtracting m m m m

Rules for Significant Figures – Multiplying and Dividing when multiplying or dividing – the final answer should have the same number of significant digits as the measurement having the least number of significant digits (regardless of where they are in relation to the decimal)

Rules for Significant Figures – Multiplying and Dividing 125.3m x7.20m m2m2 902m2m2

Mathematics – The Language of Physics physicists make their work easier by summarizing data in tables and graphs and by abbreviating quantities in equations dimensional analysis can help identify whether a physics expression is a valid one

Mathematics – The Language of Physics order-of-magnitude calculations provide a quick way to evaluate the appropriateness of an answer