Physics Basics Summary Notes Science n The study

Physics Basics – Summary Notes

Science n The study and pursuit of knowledge about the natural world. n Example A physicist tries to understand how the Sun gives us light.

Significance of Science n n n The search for knowledge adds to our understanding of the physical world. Scientists want to know! Science affects society by q q stimulating thought satisfying curiosity influencing views of the world providing knowledge necessary for new technological advances

What is Physics? n The study of motion, forces and energy. n “The entire universe is built upon of the principles revealed by a study of physics. ” -Andrew Zimmerman Jones

Technology n The application of science to meet human needs. n Example Designing and building solar panels for alternative energy automobiles

Significance of Technology n n n 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 n n n 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 1. Physics 2. Zoology 2. Chemistry 3. Botany Earth/Space Science 1. Geology 2. Meteorology 3. Astronomy

The branches of science are separate, yet integrated. Physical Science Earth and Space Science Life Science

Significance of Physics n n n 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.

Scientific Theory n A synthesis of a large body of information that is well-tested and verified and explains about aspects of the natural world. n Examples Atomic theory explains the atom Plate Tectonics explains the formation of volcanoes, earthquakes and mountains

Significance of a Scientific Theory It has been extensively tested through scientific investigation and never disproven q It grows slowly through contributions from many investigators. q Can be replaced if new evidence is discovered q

Scientific Law or Principle n n A summarizing statement about the relationship of natural quantities. A scientific fact n Example F = ma is Newton’s 2 nd Law of Motion Law of gravity Objects are gravitationally attracted to other objects (it’s a fact)

Significance of a Law n n A law demonstrates and summarizes, does not try to explain Sometimes is represented by an equation explanation vs. Newton’s Theory of Motion F = ma Newton’s 2 nd Law of Motion

Scientific Hypothesis n An educated guess that can be tested. n Example 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 n n n Drives the scientific process Has not been proved Can be adjusted and retested depending on the outcome of the first test

SCIENTIFIC MODEL n A representation of an object or event that can be studied so that the real object or event can be understood. n Examples: n A globe Computer models for hurricanes n

Significance of Models n n n 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 n n 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 n Scientific Theory: A explanation of an occurrence or phenomenon in the natural world. q Supported by evidence q Accepted as valid q Accurate at predicting and testing n Scientific Laws: Factual observations expressing a fundamental principle of science. n

Model: A representation of an object or event that can be studied so that the real object or event can be understood. n Hypothesis: a possible answer to a question; an educated guess that has not been tested. n

Variables n Anything in an experiment that can change.

Identifying Variables in a Scientific Hypothesis Independent variable (experimenter changes to see how it changes the dependent variable The three variables are underlined. 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. The if statement shows independent variable, then statement shows the dependent variable. Constant (experimenter keeps this the same) Experimental control : a test without using the independent variable, use to see if the independent variable makes a difference

MEASUREMENTS n Measurements consist of a number and a unit. n Example 100 meters the number of units the unit

INTERNATIONAL SYSTEM OF UNITS (SI units) n Developed for the sake of q q q consistency ease of understanding sharing data

BASE SI UNITS (standard units) Measured quantity

DERIVED UNITS n n Derived Units: Combinations of the 7 base units. Examples q q Area (length x width) m x m = m 2 Velocity (distance/time) = m/s 50 m 2 10 meters 5 meters

ACCURACY n Accuracy is the extent to which a measurement approaches the true value. Actual Time: 2: 10 pm Your Time: 2: 05 pm Your accuracy is off by 5 minutes

these darts show good accuracy accurate less accurate which paint ball mark is more accurate? - The bull’s eye represents the true value. - The darts represent three separate measurements

PRECISION n Precision is the degree of exactness of a measurement. n Based on the scale of the measuring instrument. Smallest tick marks represent millimeters (mm)

PRECISION VS. ACCURACY A n n B A—Good precision and accuracy B—Some accuracy and poor precision C n n D C—Good precision and poor accuracy D—Poor precision and accuracy