Concepts study guide
Concepts study guide SCMH 1010 - 002
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SCMH 1010 - 002
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This 26 page Study Guide was uploaded by kmb0095 on Wednesday February 17, 2016. The Study Guide belongs to SCMH 1010 - 002 at Auburn University taught by Allen Lee Landers in Spring 2016. Since its upload, it has received 742 views. For similar materials see Concepts of Science in Science at Auburn University.
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Date Created: 02/17/16
When scientists have finished research and wish to communicate the results, they are most likely to do which of the following? immediately repeat the research call a press conference and announce prepublication findings sell their findings to a research and development company write a concise paper and submit it to a scientific journal submit an abstract to a popular science magazine How does science differ from pseudoscience? Scientific hypotheses can be proven false through experiment. Science requires a lower standard of proof than pseudoscience. Scientific statements are based on anecdotes. Science is just one person's opinion. Science is the quest for absolute truths that never change. Why do scientists reject astrology? Planets do not exert a gravitational force on a newborn baby. Stars do not exert any force on a newborn baby. The Babylonians developed astrology. The Moon is too far away to influence a person's life. There is no evidence that stars can predict the future. How is a hypothesis tested? _1) by using the hypothesis to make predictions about a system _2) by comparing observations in nature with predictions _3) by making a new hypothesis 1 2 3 1 and 2 1, 2, and 3 The 17th century laws of planetary motion stated that: all planets orbit in circular paths. the Earth is the center of the universe. all planets orbit in elliptical paths. a planet's velocity is constant during its orbit around the Sun. Which of the following is most likely to happen to an astronaut during liftoff? Bones and muscles collapse. Nerve damage occurs. Body fluids are replenished. Blood is drained from the brain. Old wounds heal miraculously. The first three natural laws of nature were devised by: Isaac Newton. Johannes Kepler. Galileo Galilei. Claudius Ptolemy. Nicholas Copernicus. Dr. John Snow's research and observations improved the lives of London's citizens in the 1800s by: improving the quality of the drinking water. finding a cure for cholera. diagnosing tuberculosis in the Royal family. associating disease with polluted water. identifying the bacterium, Vibrio cholerae. Copernicus hypothesized that the Universe is built exactly like Ptolemy suggested except: the Sun is at the center of the universe. the Earth is at the center of the universe. the planets move in the same direction as the stars. the planets have elliptical orbits there are no rotating spheres but instead a solar system. From a physicist's point of view, in which of the following cases has significant work been done? You try to pull your car out of ditch, but it doesn't budge. Your brother throws his dirty clothes on the floor. Your mother holds a sleeping baby. You review for a test by imagining the questions. Your father tries unsuccessfully to open a jar. Which object has the greatest amount of kinetic energy? 250gram baseball hit at 50 meters/second 300gram baseball traveling at 50 meters/second 4kilogram bowling ball traveling at 7 meters per second 4kilogram bowling ball traveling at 10 meters per second a 120gram tennis ball served at 50 meters/second Which of the following balls would have the greatest amount of kinetic energy if they are all traveling at 10 m/s? baseball ping pong ball bowling ball soccer ball basketball A space capsule falling to earth would have: only kinetic energy only potential energy only chemical energy only heat energy both kinetic and potential energies Radiation is heat transfer by: electromagnetic waves of radiation. kinetic energy of molecules. stopping atomic motion. conduction. convection. What is the primary method of heat transfer in a fluid? convection conduction radiation convection and conduction conduction and radiation What is a scientific theory? a tentative, educated guess a confirmed observation about the natural world a statement of a regular, predictable pattern of behavior in nature a wellsubstantiated explanatory description of the world based on a larger number of independently verified observational and experimental tests Science affecting our daily lives is exemplified by: relying on hunches to solve crimes using DNA evidence in criminal investigations seeking the help of people with psychic visions in police work relying entirely on preconceptions to identify people who may have committed crimes Why is … a year about 365 days? Related to the motion of the earth around the sun Related to the rotation of the earth on its axis Related to the motion of the moon around the earth Related to the motion of the stars around the earth Don't know If we were somehow able to manufacture a heat engine that operated at 100% efficiency, what could we say about the temperatures of the hot and cold reservoirs? The hot reservoir is at 100 K and the cold reservoir is at 10 K. The hot reservoir can be at any temperature while the cold reservoir is at 0 K. The hot reservoir is at 100 K and the cold reservoir is at 100 K. The hot reservoir is at 10 K and the cold reservoir is at 100 K. 1. Which statement is true about the discipline of science? Science is a complete set of facts about the physical world. Science provides answers to all questions about our environment. Science provides our best view to the workings of the universe and everything within it Science and intuition are mutually exclusive. Science encompasses all of pseudoscience and more. 2. How is a hypothesis tested? 1) by using the hypothesis to make predictions about a system 2) by comparing observations in nature with predictions 3) by making a new hypothesis 1 2 3 1 and 2 1, 2, and 3 3. Linear momentum is a quantity that is equal to the: difference between an object's mass and velocity. sum of an object's mass multiplied by velocity. product of an object's mass multiplied by velocity. gravitational force multiplied by velocity. the reciprocal of an object's mass multiplied by velocity. 4. Which of the following is most likely to happen to an astronaut during liftoff? Bones and muscles collapse. Nerve damage occurs. Body fluids are replenished. Blood is drained from the brain. Old wounds heal miraculously. 5. Ockham's razor is a(n): instrument used in medical studies. philosophy advocating that the simplest solutions have a higher probability of being correct. constellation in the southern hemisphere. example of pseudoscience. tool used in raising Stonehenge's giant stones. 6. The first person to record observations using a telescope was: Isaac Newton. Johannes Kepler. Galileo Galilei. Nicholas Copernicus. 7. All popular weight loss diets are based on: the conservation law. increasing the exercise you do each day. the first law of thermodynamics. increasing protein intake. decreasing the exercise you do each day. 8. Which of the following is a rate? joule footpound power energy newton 9. Stretching a rubber band is an example of storing: electrical potential energy. kinetic energy. chemical energy. heat energy. elastic potential energy. 10.The standard used to calibrate thermometers is: pure water. pure mercury. pure ethanol. water containing 20 g. salt. liquid hydrogen. 11.Which statement about a scientific theory is true? any change to the theory effectively refutes it the theory is upgraded to a law of nature the theory undergoes constant testing and is subject to revision and refutation the theory has been conclusively proven within particular realm 12.Science can be taught of as the process of: trusting your senses relying on received wisdom asking questions, making observations, and arriving at conclusions learning lots of facts and definitions and working mathematical problems 13.An example of the difference between your weight and your mass is that: your mass is different on the Earth compared to on the Moon, but your weight remains the same. your weight decreases by a smaller fraction than your mass when you go from the Earth to the Moon. your weight is different on the Earth compared to on the Moon, but your mass remains the same. your mass decreases by a smaller fraction than your weight when you go from the Earth to the Moon. 14.If the temperature of an object changes by 5oC then it also changes by: 5 K 41oF 278 K 5oF How did Mendeleev organize the periodic table of elements? date of first discovery alphabetically atomic weight of the element total number of electrons ionization energy Which of the following scientists would study forces of motion in the universe? biologists and chemists physicists and astronomers chemists and geologists geologists and biologists chemists alone What is SETI? a pseudoscience the theory of intelligent life the search for intelligent life the application of science to astrology shortwave interference in radio signals Which statement is true about the discipline of science? Science is a complete set of facts about the physical world. Science provides answers to all questions about our environment. Science provides our best view to the workings of the universe and everything within it Science and intuition are mutually exclusive. Science encompasses all of pseudoscience and more. A truck is traveling at 30 m/s and comes to rest in 10 seconds. Its acceleration is: 30 m/s2 3 m/s2 3 m/s 30 m/s2 3 m/s Which of the following is most likely to happen to an astronaut during liftoff? Bones and muscles collapse. Nerve damage occurs. Body fluids are replenished. Blood is drained from the brain. Old wounds heal miraculously. What did the builders of Stonehenge accomplish? They demonstrated that some natural events are predictable. They figured out the structure and mechanics of the Solar System. They established contact with ancient astronauts. They maintained written records of natural events, which are carved in stone. They made a gathering place for sale of their crops. Which of the following is in uniform motion? a jet as it takes off from an airport an Olympic skier winding through a slalom course a high diver spinning in the air a train traveling west at 70 mph If you were in a spacecraft moving away from the earth: your mass would be increasing. your weight would be decreasing. your weight would be increasing. your mass would be decreasing. your weight would not change. Stretching a rubber band is an example of storing: electrical potential energy. kinetic energy. chemical energy. heat energy. elastic potential energy. What kind of energy does the pounding of ocean surf demonstrate? kinetic energy potential energy sound energy heat energy mechanical energy To calculate how many calories your body needs to maintain your current weight for a week, you need to know all of the following EXCEPT: your current weight. the approximate amount of energy you expend each day. the number of calories used daily for normal body maintenance. the recommended weight for your height. the number of days in the week. Which of the following balls would have the greatest amount of kinetic energy if they are all traveling at 10 m/s? baseball ping pong ball bowling ball soccer ball basketball From a physicist's point of view, in which of the following cases has significant work been done? You try to pull your car out of ditch, but it doesn't budge. Your brother throws his dirty clothes on the floor. Your mother holds a sleeping baby. You review for a test by imagining the questions. Your father tries unsuccessfully to open a jar. If one were to introduce a fast moving molecule into a container of slower moving molecules the outcome will be: the fast moving molecule will remain moving faster than the other molecules. all molecules will end up traveling the same speed. the fast moving molecule will end up traveling slower than the other molecules. all molecules will lose speed. all molecules will end up traveling the speed of the fast molecule. Temperature is a measure of: the amount of heat in a substance. the average potential energy of the atoms within a substance. the average kinetic energy of the atoms within a substance. how much energy a substance contains. how fast heat is moving in a substance. Daniel Fahrenheit invented a thermometer on which 0 represented: the freezing point of water. the melting point of ice. the coldest temperature he could obtain in his laboratory. the coldest day where he was conducting his experiments. the temperature of ice cream. What do all thermometers have in common? digital display mode having some mercury inside work only when upside down measure temperature by radiation materials inside change when heated Which statement best represents the second law of thermodynamics? Heat will not flow spontaneously from a hot to a cold body. Every isolated system becomes more disordered with time. Scientists have constructed an engine that does nothing but convert heat to useful work. The total amount of energy in the universe is constant. Energy may change from one form to another over and over again. Which statement about a scientific theory is true? any change to the theory effectively refutes it the theory is upgraded to a law of nature the theory undergoes constant testing and is subject to revision and refutation the theory has been conclusively proven within particular realm Which of the following could not be investigated by the scientific methods? the percentage of people who like a new novel the monetary worth of a renown painting the intrinsic artistry in a piece of classical music the age of a wellknown oil painting Which of the following is the best definition of energy? The ability to do work The amount of work in an object The measure of the force in an object The size of the force acting on an object In pushing a crate 3.0 m across a floor using a force of 10 N, how much work did you expend on the crate? 10 J 20 J 30 J After mixing the ingredients for a salad, why do the ingredients (lettuce, tomato, cabbage, carrot, etc.) remain mixed? In other words, why do they not unmix themselves? The Law of Conservation of Energy tells us that this will not happen. The statistical likelihood of this happening is so low that the chance of it happening is essentially zero. Newton's 1st Law of Motion tells us that this will not happen. Notes: In the assigned video, how did the speaker say science was best described? Farting around in a dark room Pursuit of Ignorance o Scientists spend their time talking about what they don’t know o Not knowing is cool, its an opportunity to learn something o In science, we want to learn about nature (gravity, solid vs gas, proportions of forces, etc.) o Black cat in a dark room in a dark room, especially with no car o What’s interesting in science is what we don’t know o Marie Curie – “one never notices what has been done; one can only see what remains to be done…” As a scientist, one can only focus on the future Figuring out what we don’t know tells us where to look o Ignorance : James Clerk Maxwell – “thoroughly conscious ignorance is the prelude to every real advance in science” Scientific knowledge o Basically there’s 3 new scientific papers per minute Knowledge vs. ignorance o Knowledge – big subject o Ignorance is bigger o George Bernard Shaw – “Science is always wrong. It never solves a problem without creating 10 more.” o Immanuel Kant – “Every answer given on principle of experience begets a fresh question.” Chapter outline: The role of science The scientific method Other ways of knowing The organization of science The role of science o Making choices Be an informative citizen Knowledge enables you to make decision based on understanding, not on what others tell you Why study science? o Most powerful tool for understanding o Incorporates basic ideas and theories o Provides framework for new questions o Provides unparalleled view of order and symmetry of the universe and its workings Observation o History Greek philosophers Middle ages Alchemist laid the foundation for modern chem o Alchemy – just mixing stuff together, melt this blend that, to turn lead into gold o Alchemist knew lead and gold were extremely similar, knew if they succeeded they’d be extremely rich Advances in mathematics due to first discoveries o Done to help understand science Navigation: magnetism o Observation – no manipulation Just look and see what’s happening, as soon as you manipulate then it becomes experimentation Maybe difficult in astronomy, biology, geology – very observational, hard to manipulate in these fields o Experiment – manipulation o Physics/chem lab You notice that when the parchment paper of an ancient document is exposed to a certain chemical, the parchment paper becomes a different color. What have you done? Performed an experiment Which of the following is least likely to be categorized as ‘science’? determining the aesthetic properties of a famous poem Science can be thought of as the process of: asking questions, making observations, and arriving at conclusions Science affecting our daily lives is exemplified by: using DNA evidence in criminal investigations Science and objectivity o Science isn’t about opinions Keep science objective o What makes an article a ‘scientific journal’ article Peer review process – reviewed by other scientists o Example of the ‘scientific literature’ What is the purpose of peer review in science? It uses anonymous experts who determine the worthiness of a particular piece of research Quantitative analysis o What does it mean for two quantities to be proportional? o What does it mean for two quantities to be inversely proportional? Move in opposite directions o Units obey the equations o Speed (mph) = distance/time The symbolic equation A=kB means which of the following? A is proportional to the cube of B Measurements presented visually in the form of a graph o Accelerating a time goes on o Galileo Which statement does not describe a falling object? Distance equals a constant multiplied by time Correct: - D = a constant multiplied by (time) 2 - The distance traveled is proportional to the time traveled multiplied by the time traveled - Time squared multiplied by a constant equals distance - If an object falls three times as long as another, it will travel nine times as far as another Week 2 1/27/16 Mathematics: the language of science o Description General Mathematical o Mathematics Equation Description Fact, hypothesis, laws, and theories o Fact Confirmed observation Objects fall Iron rusts There are different species of plants and animals There are other stars and galaxies o Hypothesis Educated guess o Law Description of nature Law of gravity o Theory Well-substantiated description Newton’s Theory of Movement Relativity Theorem Theory of Chemical Reactions Theory of Evolution Theory of Big Bang Which of the following statements would be true of a theory? The word theory in science can refer to an unproven hypothesis or one that has been tested many times and not disproven (Landers); the word theory in science is only used when a hypothesis has been tested many times and not disproven (book) Occam’s Razor o A principle attributed to the 14 century English logician, theologian and Franciscan friar William of Ockham o The simplest explanation is usually the correct one. Here, simplest referring to the theory with the fewest new assumptions Prediction and Testing o Predictions Hypothesis, theory, law Must be quantitatively testable o Testing Do not prove or disprove immediately Define range of validity Classical mechanics/quantum mechanics o Every law and theory of nature is subject to change, based on new observations We don’t believe this or believe that, we have evidence that shows us The scientific method in operation o Cycle Not rigid o Believe results No fixed preconceptions o No true starting place o Results must be reproducible o Cycle is continuous The ongoing process of science o Dynamic process of scientific research Science in the making o Dimitri Mendeleev and the Periodic Table The science of life o William Harvey and the blood’s circulation Pseudoscience o Believe, dogma o Ideas not testable o Evaluation of a claim Are the ‘facts’ true as stated? Is there an alternative explanation? Is the claim falsifiable? Have claims been tested? Do claims require unreasonable changes in accepted ideas? o Fortune telling 1/29/16 The Ordered Universe (ch.2) o Great Idea: Newton’s laws of motion and gravity predict the behavior of objects on Earth and in space o Fundamental idea Physical events are quantifiable and therefore predictable Throw something up for a second, it falls Do it again, it’ll have the same result Without the predictability of physical events, pursing science is not possible o The night sky Movement of stars, planets, sun was key for survival of ancestors Astronomy – first science Ancient observers Physical events are quantifiable and therefore predictable o Stonehenge, Wiltshire, UK Aligned to know when summer solstice is Midsummer solstice is easier to observe than equinox What did the builders of Stonehenge actually accomplish? Demonstrated that some natural events are predictable o Sun Dagger – Chaco Canyon, NM Sun dagger at equinox o Chichen Itza, Yucatan, MX Snake image at the equinox at El Castillo o Astronomy and time Why is a day about 24 hours? Related to the rotation of the earth on its axis Why is a month about 30 days? Related to the motion of the moon around the earth (moon orbits the earth in ~30 days, earth orbits the sun in ~365 day) Why is a year about 365 days? Related to the motion of the earth around the sun ^^ o The historical background: Aristotle (~350 BC) Aristotle was the final word on any scientific question th influenced scientific thought until the end of the 17 century believed that the natural state of object was to be at rest Ptolemy (2 ndcentury AD) First planetary model Earth at center, stationary Stars and planets revolved around earth Geocentric Model “geo” = “earth” o planetary motion – changing ideas geocentric view persisted for almost 2000 years until being challenged in the 1500s Nicholas Copernicus (1473-1543) o “Heliocentric model” – sun at the center o 1543: On the Revolutions of the Spheres published after death for fear of the church Tycho Brahe (1546-1601) o “first observatory” o did highly detailed observations of planet motion WITHOUT a telescope o showed that Ptolemy’s geocentric model had flaws: why should planets back up on their paths? o Introduction to the new astronomy (1588) Johannes Kepler (1571-1630) o “laws of planetary motion” o used Tycho’s observations to develop the laws of planetary motion o A New Astronomy – 1609 o A strong endorsement of the Copernicus (heliocentric) view o 3 laws: the orbit of a planet is an ellipse with the sun at one of the two foci a line segment joining a planet and the sun sweeps out equal areas during equal intervals of time the square of the orbital period of a planet if proportional to the cube of the semi-major axis of its orbit What were the two models that were used to describe the motion of the planets? Geocentric and Heliocentric o The Birth of Mechanics Galileo Galilei “first true astronomer” Mechanics: motions of material objects Mathematics professor, inventor First to record observations with telescope o Supported Copernicus’ view o Observed moons of Jupiter o Measured speed of light o Science in the Making The Heresy Trial of Galileo (~1610) Heliocentric model contrasted both established church dogma and writing in the Old Testament Galileo almost got burnt at the stake o Giordano Bruno burnt at stake in 1600 for teaching Copernicus’ model First clash bw science and religious dogma 350 years later, Galileo’s findings were accepted by the church Week 4 2/1/16 Kepler’s first law of planetary motion says: o Planets orbit the Sun along elliptical paths The Founder of Experimental Science o Galileo Relationship among distance, time, velocity, and acceleration Found objects accelerate constantly while falling Speed, Velocity, and Acceleration o Speed = distance traveled over time o Velocity = speed with direction m distancetraveled(m) o Equation for speed: Velocity∨speed( ) = s timeof travel(s) o Acceleration = rate of change of velocity m ( finalvelocity−initial velocity) o Equation for velocity: Acceleratio( ) = time s o The measurement of how velocity is changing over a period of time is called: Acceleration o If you multiply the units (meters/second ) x (second) the result is the unit: meters/second o Galileo Discovered acceleration is constant: v = at Constant acceleration at g g = 9.8 m/s = 32 ft/s 2 2 Distance traveled (d) = ½ (at ) o A train travels at an average speed of 100 miles per hour for 30 minutes. How far does it travel? 50 miles o A car increased speed from 10 m/s to 15 m/s in 5 seconds. What is its acceleration? 1 m/s2 Isaac Newton and the Universal Laws of Motion o First Law — “Law of Inertia” An object will continue moving in a straight line at a constant speed, and a stationary object will remain at rest, unless acted upon by an unbalanced force An object will keep going unless force acts upon it then force changes things Uniform motion vs. acceleration Force Inertia o Second Law The acceleration produced on a body by a force is proportional to the magnitude of the force and inversely proportional to the mass of the object Equation: F=ma o Third law Interacting object exerts equal but opposite forced upon each other The reactions may not be equal and opposite We could give an object an acceleration of 2 m/s when we push on it with a total force of 10 N. What is the mass of the object? 5 kg 2/3/16 Vectors o Quantity that has both magnitude and direction o Ex) 30 miles north, 10 ft. left, 10 mph south, push down o a = change in velocity / change in time Scalar o Quantity that only has magnitude (no direction) o Ex) 1 kilo, 30 degrees, 2 ML Which of these quantities is not a vector? Mass A car initially moving towards the west at a speed of 15 m/s changes its velocity to 25 m/s towards the west in 5 seconds. What is the cars acceleration? 2 m/s towards the west A car initially moving towards the west at a speed of 15 m/s changes its velocity to 25 m/s towards the west in 5 seconds by braking. What is the cars acceleration? 2 m/s towards the east Momentum o Newton’s Cradle o motion depends on mass and speed o linear momentum: p=mv o law of conservation of linear momentum force F = change in momentum F=0 change in momentum is 0 v (change in mass) + m a = 0 principle of rocket that’s how a rocket works – change velocity o no outside force linear momentum is preserved collisions, car wrecks Week 5 2/8/16 kin (ch.3) o great idea: the many different forms of energy are interchangeable, and the total amount of energy in an isolated system is conserved o the great chain of energy scientifically speaking energy related to force Work o force over distance o formula: W = Fd o Units: joules Energy o Ability to do work Power o Rate at which work is done o Equation: P = W/t or (E – f)/ti o Units: watts Basic ideas Energy can be provided/stored in various forms Food is one way to store energy. Our bodies store energy in the form of fat, which can be converted back in terms of low availability of food Other units for energy A calorie is the energy needed to increase the temperature of 1 gram of water be 1 degree Celsius (4.2 J) A kilocalorie (aka food calorie) is the energy needed to increase the temperature of 1kg of water by 1 degree Celsius, this is exactly 1000 small calories (4.2 kJ) Kinetic energy Energy of moving object Mass and speed o Directly proportional to KE Equation = E =k1/2mv 2 Potential energy Energy waiting to be released Grav PE o E = mgh p Chem PE Electrical PE Magnetic PE James Watt’s first “sun and planet” steam engine Efficiently converted potential chemical energy (coal) into KE Breaching humpback whale has KE bc he is moving The KE is mostly converted into PE the moment the whale reaches the highest point Heat or thermal energy Atoms and molecules o Bonding Motion o Force Thermal energy o Heat o Random KE of atoms and molecules Discovering the nature of heat The friction created drilling the barrels of cannons was converted into heat Wave energy Wave Sound wave Seismic wave Electromagnetic radiation Mass as energy Radioactivity Einstein o Equation: E = mc 2 o Energy (J) = mass (kg) x speed of light (m/s) 2 Can convert mass to energy 2/10/16 The Interchangeability of Energy Some forms of energy o Example of energy changing from one to another: slinky Energy changes form during a bungee jump Energy hitting the earth o Radius of Earth = 6.375 million meters 2 o Solar energy power = 1400 W/m o How much power hits the earth?? o A = 1.2 x 10 14m 2 o P = 1.7 x 10 W17 Energy for Life and Trophic Levels o Energy is Conserved o Closed: Energy neither enters not exits o Open: Energy can come in or go out Law of Conservation of Energy o Total energy in system is conserved o Type of energy vs. total The US and its Energy Future o Fossil fuels Oil, coal, natural gas o Renewable energy sources Solar energy, wind o Base load vs. Peak load Sources of Energy for the US as of June 2014 o Petroleum—36% o Natural gas—27% o Coal—19% o Renewable—10% o Nuclear—8% The main source of energy used in the US is oil Electricity generated from wind turbines Solar Photovoltaic panels can be used in various ways Solar thermal facility in Barstow, California Transportation o Electric vehicles Battery Short range o Hybrid vehicles Gas and battery Many new models o Fuel cell vehicles Hydrogen Uses fossil fuels to create hydrogen 2/12/16 Ch.4 First Law of Thermodynamics—Law of Conservation of Energy o Does not prevent things to go to a more disorderly state o Fast atoms collide with slower atoms, energy is transferred to slower ones, equilibrium is eventually reached Second Law of Thermodynamics—Tendency for disorder o Things will not order themselves o Deck of cards getting shuffled more = more disorder o Evolution to a more probable state Entropy = measurement of disorder increases It takes energy to reverse the process After mixing the ingredients for a salad, why do the ingredients remain mixed? The statistical likelihood of this happening is so low that the chance of it happening is essentially zero Heat and energy o Energy in motion o Warm to cool o Heat is a measure of energy flow Temperature is a measure of atomic movement Temperature Scales o Fahrenheit scale o Celsius o Kelvin Absolute zero If the temperature of an object changes by 5°C then it also changes by: 5K Conversion to Fahrenheit o °F = (1.8 °F/°C x °C) + 32 °F o 30°C = (1.8°F/°C x 30°C) + 32 °F = 86°F Conversion to Celsius o °C = (°F - 32°F)/1.8°F/°C o 104°F = (104°F - 32°F)/1.8 °F/°C = 40°C Specific heat capacity o Quantity of heat need to raise 1g of a substance by 1 °C Water o Highest specific heat o 1 cal/g °C Conduction o Movement of heat by atomic scale collision o Thermal conductivity Convections o Bulk transfer of molecules o Convection cells are also the driving force behind the currents of the oceans Radiation In a room that is heated by a floor-mounted radiator near a wall, in which of the following locations would you find the coolest air? Near the floor at the bottom of the wall directly opposite the radiator Week 6 2/15/16 Radiation (cont’d) o Electromagnetic waves (usually IR) o Come about from the charges in the atoms and/or molecules of a material o Essentially light, charges that move around give off these waves that are pure energy The mode of heat transfer that takes advantage of differences in density is: convection Liquid Nitrogen boils at a temperature of 77K. This corresponds to: -321 F (77 – 273 = -196 C, which is 9/5(-196) + 32) Second law of thermodynamics (tendency for disorder) o More likely to go to disorder than to go to order o 3 statements of the law heat does not flow spontaneously from cold to hot no engine can exclusively convert heat to work when we talk about efficiency of engines, and temperature of various types of fuels, our discussion is based on the fact that every engine reaches a highest and a lowest temp in its working cycle high temp creates a high temp reservoir (T ) hot low temp created a low temp reservoir (T cold Eff (%) = 100*(T hot– Tcold / hot o T hot= 350 C = 623 K Tcold 100 C = 373 K Eff = (623K – 373K) / 623K *100 = 40% If we were to somehow able to manufacture a heat engine that operated at 100% efficiency, what would we say about the temps of the hot and cold reservoirs? The hot reservoir can be at any temp while the cold reservoir is at 0K every isolated system tends toward disorder (your room will not clean itself) ordered system o regular predictable pattern disordered system o random entropy o measure of disorder o the entropy of an isolated system remains constant or increases (will always become more disordered) Which of the following is NOT a statement from the Second law? Living things must be able to absorb heat from their environment by radiation Water (H 2) is at lowest entropy (least disordered) when it is in the form of:
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