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Physics Basics – Summary Notes. The study and pursuit of knowledge about the natural world. Example A physicist tries to understand how the Sun gives us light. Science. Significance of Science. The search for knowledge adds to our understanding of the physical world.
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The study and pursuit of knowledge about the natural world. Example A physicist tries to understand how the Sun gives us light. Science
Significance of Science • The search for knowledge adds to our understanding of the physical world. • Scientists want to know! • Science affects society by • stimulating thought • satisfying curiosity • influencing views of the world • providing knowledge necessary for new technological advances
The study of motion, forces and energy. “The entire universe is built upon of the principles revealed by a study of physics.” -Andrew Zimmerman Jones What is Physics?
The application of science to meet human needs. Example Designing and building solar panels for alternative energy automobiles Technology
Significance of Technology • Put the findings of science to use • Try to solve practical problems • New technology often leads to new discoveries and the advancement of science
Examples of Technologies that led to the Advancement of Science • Telescope…used to discover new planets, moons and stars • Microscope…used to discover microorganisms that cause disease, such as bubonic plague • Internet and computer…processing a huge amount of data in a matter of seconds
The Branches and Disciplines of Science Natural Science Life Science Physical Science 1. Biology 2. Zoology 3. Botany Earth/Space Science • 1. Geology • Meteorology • Astronomy 1. Physics 2. Chemistry
The branches of science are separate, yet integrated. Physical Science Earth and Space Science Life Science
Significance of Physics • Foundation for other sciences. • Everything around us is affected by it. • Explains phenomena such as orbiting satellites, weightlessness, lightning, sonic booms, magnetism and energy transformations.
A synthesis of a large body of information that is well-tested and verified and explains about aspects of the natural world. Examples Atomic theory explains the atom Plate Tectonics explains the formation of volcanoes, earthquakes and mountains Scientific Theory
Significance of a Scientific Theory • It has been extensively tested through scientific investigation and never disproven • It grows slowly through contributions from many investigators. • Can be replaced if new evidence is discovered
A summarizing statement about the relationship of natural quantities. A scientific fact Example F = ma is Newton’s 2nd Law of Motion Law of gravity Objects are gravitationally attracted to other objects (it’s a fact) Scientific Law or Principle
Significance of a Law • A law demonstrates and summarizes, does not try to explain • Sometimes is represented by an equation explanation vs. F = ma Newton’s Theory of Motion Newton’s 2nd Law of Motion
An educated guess that can be tested. Example Scientific Hypothesis If the mass on a cart is increased, then the cart’s rate of acceleration will decrease given the same force.
Significance of a Scientific Hypothesis • Drives the scientific process • Has not been proved • Can be adjusted and retested depending on the outcome of the first test
A representation of an object or event that can be studied so that the real object or event can be understood. Examples: A globe Computer models for hurricanes SCIENTIFIC MODEL
Significance of Models • A model can be tested by comparing its predictions to actual observations in the real world. • Can use scientific method by changing one variable to see how it affects the other variable(s). • A close match does not necessarily mean that the model is the only “true” model or the only one that would work.
Theory vs…law/hypothesis/model • Theory is an explanation that has been proved through testing • Law is a summary (often expressed as an equation) • Hypothesis is an question or educated guess that can be tested (but has not been tested) • A model is a representation of something that can be used to study it.
Fact: something that is observed to be real • Scientific Theory: A explanation of an occurrence or phenomenon in the natural world. • Supported by evidence • Accepted as valid • Accurate at predicting and testing • Scientific Laws: Factual observations expressing a fundamental principle of science.
Model: A representation of an object or event that can be studied so that the real object or event can be understood. • Hypothesis: a possible answer to a question; an educated guess that has not been tested.
Variables • Anything in an experiment that can change.
Identifying Variables in a Scientific Hypothesis The three variables are underlined. Independent variable (experimenter changes to see how it changes the dependent variable Dependent variable (changes depends on the influence of the independent variable If the mass on a cart is increased, then the cart’s rate of acceleration will decrease given the same force. Constant (experimenter keeps this the same) The if statement shows independent variable, the then statement shows the dependent variable. Experimental control : a test without using the independent variable, use to see if the independent variable makes a difference
Measurements consist of a number and a unit. Example MEASUREMENTS 100 meters the number of units the unit
INTERNATIONAL SYSTEM OF UNITS (SI units) • Developed for the sake of • consistency • ease of understanding • sharing data
BASE SI UNITS (standard units) Measured quantity
DERIVED UNITS • Derived Units: Combinations of the 7 base units. • Examples • Area (length x width) m x m = m2 • Velocity (distance/time) = m/s 50 m2 5 meters 10 meters
Accuracy is the extent to which a measurement approaches the true value. ACCURACY Actual Time: 2:10 pm Your Time: 2:05 pm Your accuracy is off by 5 minutes
- The bull’s eye represents the true value.- The darts represent three separate measurements these darts show good accuracy accurate which paint ball mark is more accurate? less accurate
Precision is the degree of exactness of a measurement. Based on the scale of the measuring instrument. PRECISION Smallest tick marks represent millimeters (mm)
A—Good precision and accuracy B—Some accuracy and poor precision C—Good precision and poor accuracy D—Poor precision and accuracy PRECISION VS. ACCURACY A B C D