Introduction to Physics

Mrs. Tsimberg … I’ll have you introduce yourselves later in class to break things up a bit!

WHAT is PHYSICS? The study of matter, energy, and the interactions between them … in other words, everything! What do you think these quotes really mean? “Physics investigates the essential nature of the world, and biology describes a local bump. Psychology … describes a bump on a bump.” Willard Van Orman Quine, American philosopher (1908 – 2000)

Branches of Physics  Mechanics –matter, motion, forces, and energy. Only describes objects bigger than atoms and slower than light.  Thermodynamics –heat and temperature  Electromagnetism - electricity, magnetism, and light  Relativity –particles moving at any speed, including very high speeds  Quantum Mechanics – behavior of submicroscopic particles

Side Note  Theory of Classical Mechanics worked perfectly for more than 100 years – and still works in most circumstances today.  Leaders of Modern physics (Einstein, Planck, Bohr, etc.) had to be open-minded when data didn’t fit with established theories “No amount of experimentation can ever prove me right; a single experiment can prove me wrong” -- Albert Einstein

Which Branch(es)?  Preparing dinner  A Soccer game  Lightning in a thunderstorm  A car accident  Lasers

Class structure Major Objectives  Understand physical phenomena not just equation hunt  Build problem-solving abilities  Communicate scientific knowledge simply and precisely using math, graphs, pictures, and words Assessment  Daily work 20%  Labs & Projects20%  Major Quizzes and Exams60% No work or unintelligible work = no credit!

Class structure Rules  Respect each other’s time and learning  Bring calculator every day!  NO computers or phones (unless I specify)  Non-distracting food / drink is ok Keys to success  Practice, Practice, Practice!  Get help early & often … then try again on your own  DON’T GIVE UP … studies say the single most important factor in success at any task is GRIT

Your turn … Pick 2 Introduce yourself and pick 2 things to share with the class Something factual  Favorite hobby / activity / unusual talent  Something interesting from the summer  Something about your family  Farthest / most exotic place you’ve traveled Something you wish  Dream job (even if its not realistic)  Dream home / travel  Dream talent / experience

Unit 1: Vectors and Math skills Statement of Inquiry: Math is a tool for explaining physical phenomenon AOI: Human Ingenuity Todays Objectives:  Define physics and describe the types of phenomena studied by each branch of physics  Differentiate between scientific theories, laws, and hypotheses  Express numbers in scientific notation  Recognize SI prefixes

The nature of science Scientific ideas are developed by making and testing predictions. Nothing is ever proven in science, tests can merely support or disprove an idea. … but some ideas have more support than others Hypothesis – Theory – Law –

The nature of science Scientific ideas are developed by making and testing predictions. Nothing is ever proven in science, tests can merely support or disprove an idea. … but some ideas have more support than others Hypothesis – educated guess Theory – Law –

The nature of science Scientific ideas are developed by making and testing predictions. Nothing is ever proven in science, tests can merely support or disprove an idea. … but some ideas have more support than others Hypothesis – educated guess Theory – one (or several related) hypotheses that have been tested and supported many many times; usually explain why something happens Law –

The nature of science Scientific ideas are developed by making and testing predictions. Nothing is ever proven in science, tests can merely support or disprove an idea. … but some ideas have more support than others Hypothesis – educated guess Theory – one (or several related) hypotheses that have been tested and supported many many times; usually explain why something happens Law – generalizes a body of observations with no known exceptions; only describes events does NOT explain why

The nature of science Scientific ideas are developed by making and testing predictions. Nothing is ever proven in science, tests can merely support or disprove an idea. … but some ideas have more support than others Hypothesis – educated guess Theory – one (or several related) hypotheses that have been tested and supported many many times; usually explain why something happens Law – generalizes a body of observations with no known exceptions; only describes events does NOT explain why Example: Newton’s Law of Gravitation is an equation that generalizes force of attraction between 2 or more objects. Einstein’s Theory of Relativity is a (well supported) idea about why masses exert forces on other masses

Hypothesis, theory, or law? a. Male pupfish have bright colors to attract mates b. Animals change over time c. Traits that confer a reproductive advantage tend to increase in a population over time hypothesis Law of Evolution Theory of Natural Selection How do you know?

The mass of the Earth is kg Is this a reasonable way to express this measurement? Of course not! Much better way: X kg This is known as scientific notation About Measurements…

The mass of the Earth is kg Much better way: X kg This is known as scientific notation

Scientific Notation To write a number in scientific notation:  put one non-zero digit to the left of the decimal  multiple the number by a power of 10 to get correct magnitude Examples: = ? = ?

Scientific Notation To write a number in scientific notation:  put one non-zero digit to the left of the decimal  multiple the number by a power of 10 to get correct magnitude Examples: = X = 1.56 X 10 8

Scientific Notation Practice individually. If you have time, check with table partner. You have 3 minutes. 1) ) ) ) ) X (convert to expanded form!) 6) X 10 4 (convert to expanded form!)

Scientific Notation Practice individually. If you have time, check with table partner. You have 3 minutes. 1) =3.004 X ) =4.56 X ) = X ) 9340= X ) X = ) X 10 4 =

Why use Scientific Notation? Scientific notation is useful 1) For very large or small numbers 2) For showing the precision of a measurement Example: If I say a pumpkin is 200 lb, what do I really mean? Maybe I mean that it is exactly 200 lbs (closer to 200 lbs than to 201 or 199 lbs). But, maybe I mean that is only roughly 200 lbs (closer to 200 lbs than 300 or 100 lbs) If I say that a pumpkin is 2.00 X 10 2 lbs, the precision is clear … it is between 201 and 199. More on this, later! How else might we handle very small or large numbers? SI prefixes!

SI Units Who knows what SI units are? The International System of Units (abbreviated SI from French: Système international d'unités) is the modern form of the metric system adopted in Why use SI units? * universal * easy

SI Prefixes PowerPrefixAbbr.PowerPrefixAbbr femto- f centi- c pico- p 10 3 kilo- k nano- n 10 6 mega- M micro- μ 10 9 giga- G milli- m tera- T ! Note: These are prefixes. They go before the base unit (L, m, g, etc.) Where does the base unit fit in? 10 0 Which is bigger a mm or a Mm? a ng or a g? Mm g

SI Prefixes PowerPrefixAbbr.PowerPrefixAbbr femto- f centi- c pico- p 10 3 kilo- k nano- n 10 6 mega- M micro- μ 10 9 giga- G milli- m tera- T Just for Fun Diameter of atomic nucleus ≈ 5 fm !

SI Prefixes PowerPrefixAbbr.PowerPrefixAbbr femto- f centi- c pico- p 10 3 kilo- k nano- n 10 6 mega- M micro- μ 10 9 giga- G milli- m tera- T Just for Fun Diameter of the atom ≈ 100 pm !

SI Prefixes PowerPrefixAbbr.PowerPrefixAbbr femto- f centi- c pico- p 10 3 kilo- k nano- n 10 6 mega- M micro- μ 10 9 giga- G milli- m tera- T Just for Fun Diameter of a red blood cell ≈ 8 μ m !

SI Prefixes PowerPrefixAbbr.PowerPrefixAbbr femto- f centi- c pico- p 10 3 kilo- k nano- n 10 6 mega- M micro- μ 10 9 giga- G milli- m tera- T Just for Fun Diameter of Earth ≈ 13 M m !

SI Prefixes PowerPrefixAbbr.PowerPrefixAbbr femto- f centi- c pico- p 10 3 kilo- k nano- n 10 6 mega- M micro- μ 10 9 giga- G milli- m tera- T Just for Fun Diameter of sun ≈ 1.4 G m !

SI Prefixes PowerPrefixAbbr.PowerPrefixAbbr femto- f centi- c pico- p 10 3 kilo- k nano- n 10 6 mega- M micro- μ 10 9 giga- G milli- m tera- T Just for Fun Diameter of Milky Way ≈ 9500 T m ! Watch me!

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