Create Presentation
Download Presentation

Download Presentation

Physics Chapter 1, The Science of Physics

Download Presentation
## Physics Chapter 1, The Science of Physics

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**Physics Chapter 1, The Science of Physics**From: Holt Physics, 2006**Areas within Physics**• *Mechanics: Studies motion and interactions between objects. • Examples: Falling objects, friction, weight, spinning objects.***Thermodynamics**• *Studies heat and temperature. • Examples: melting and freezing processes, engines, refrigerators.***Vibrations and Waves**• *Deals with repetitive motions. • Examples: Springs, pendulums, sound***Optics**• *Studies Light • Examples: Mirrors, lenses, color, astronomy***Electromagnetism**• *Deals with electricity, magnetism, and light • Examples: Circuits, electronics***Relativity**• *Studies particles that are moving at any speed, even very high speeds • Examples: traveling at high speeds, particle accelerators, particle collisions.***Quantum Mechanics**• *Studies the behavior of submicroscopic particles. • Examples: The atom and its parts**Scientists use the Scientific Method to investigate things.**• 1. Make observations and collect data that lead to a question. • 2. Make a hypothesis • 3. Test Hypotheses by using experiments. • 4. Interpret results, and revise the hypothesis if necessary. • 5. Make conclusions. • *A Hypothesis is an explanation you make to account for your observations.**Models are simplified representations that are used to**explain complex things. • Many times a model is a diagram or a computer simulation.**Computer**Simulation**A good physics model can predict what will happen in new**situations. • If a model does not correctly predict what will happen, it needs to be changed.**A System is the specific things you want to study. For**example, studying the circuitry of a TI-82 Calculator.**A controlled experiment tests one factor at a time.**• Controls are held constant in the experiment.**Create a fair race to see which animal, on average, is**faster over 100 m**See which type of barbeque sauce people in America like**better: • Sweet and Tangy: Hot and Spicy: BBQ BBQ**Section 2, Measurements in Experiments**• Dimension describes the kind of physical quantity you are measuring. • Three basic dimensions are length, mass, and time. • These three are used in different combinations to describe many things like force, velocity, energy, etc.**How much of something you have is given by Units. Like**centimeters, kilometers, etc. • SI is the standard measurement system for science. • Each unit is defined by a standard, for example, a “Meter is officially the distance light travels, in a vacuum, in 1/299,792,458 seconds with time measured by a cesium-133 atomic clock which emits pulses of radiation at very rapid, regular intervals.” from: http://www.surveyhistory.org/the_standard_meter1.htm**Prefixes can be used in front of units to mean powers of 10.**• Micro = 10-6, like a micrometer. This means that there are 10-6 meters in a micrometer. • Kilo = 103, This means that there are 103 meters in a kilometer.**Scientific Notation**• 1,400,000 = 1.4 x 106 • .00056 = 5.6 x 10 —4**Units Conversion:**• Use Conversion Factors to convert from one unit to another. • Conversion Factors are always equal to 1. Like: 1 mm / 10-3 m = 1. Or 106 m / 1 Megameter = 1. See Table 3 in book.**Example, convert 7 mm to m.**Example 2: Convert 12.4 megameters to centimeters.**Convert 4 m3 to cm3:**• Convert 6,000 m3 to km3 • Convert 7 km/s2 to m/s2***Accuracy and Precision**• *Accuracy: How close a measurement comes to the correct value. • *Precision: How close a series of measurements are to one another. Or, how exact a measurement can get, based on the instrument you are using.**Method error = An error caused by taking some measurements**with one process, and using a different process to take other measurements. • Instrument error Errors caused by faulty equipment.**Determining Error of a measurement**• Error = [Experimental Value - Accepted Value] • Percent Error = error / accepted value * 100% • Example, you measured 120 cm, but it is 130 cm.**Significant Figures: The digits in a measurement that are**known with certainty, plus one digit that is estimated.**Is a Zero a Significant Number or Not?**• Table 4 in book. • 504 • .006 • 50.0 • 7,000**Sig Figs in Calculations:**• Addition or subraction Round the final answer to the last “shared column”. • 13.4 + 5.234**Sig Figs in Calculations:**• Multiplication or Division The final answer should have the same number of sig figs as the measurement that had the least # of sig figs. • 1.50 x 2.0**Infinite Sig Figs**• Exact Quantities have an infinite number of sig figs. • Like: I am holding 4 paperclips • Or: There are 12 inches in a foot**In this class, delay rounding until the very end.**• (3.449 + 6.57) * 8.779 / 5.2**Tables and Graphs are important in Physics, and any science.****Physics Equations describe relationships.**• V = d/t • F = m * a**Symbols in equations: Delta, Sigma**• Notice how variables are bold or italicized. • Table 8 F = m * a • Units are not italicized.**On the Test: (What do the graphs look like?)**• Y = mx + b • Y = 2x + b • Y = x + 3**On the Test: (What do the graphs look like?)**• Y = x^2 • Y = x^2 + 1 • Y = 3x^2