1Welcome to PHYS 001Instructor:Amber L. Stuver22Syllabus• Course web page:– http://www.gravity.psu.edu/~stuver/teaching/phys001/• Lectures will be held EVERY weekday from 11:15am – 12:25pm• Attendance will not be recorded but homework will be collected randomly in lecture• There will be a midterm and a comprehensive final• There will be a term projectGo over the syllabus in more detail in lecture.3Chapter 1About Science44Science is not “Truth”• History is full of examples where statements accepted as true have been proven false• That is not to say that science is not true, but science has a built in mechanism to correct itself when experiments show that a scientific “fact” is false• But, science is constructed by humans with egos –sometimes even scientists have trouble “letting go”Note Copernicus heliocentric universe and Galileo’s house arrest.Galileo also proved that a heavier ball does not fall faster than a lighter ball, contrary to Aristotle’s conviction which held for nearly 2000 years – if Aristotle was wrong about this, what else could he be wrong about?55Scientific Measurements• Science is all about observation – if you can’t observe (measure) something, then it isn’t science• The units of measurements in science are metric units:1.6 km ~ 1 mi 1 m ~ 1 yd 2.5 cm ~ 1 in1 kg ~ 2.2 lb 1 l ~ 1.05 qt 5 ml ~ 1 tspNote that kilo = 1000, centi = 1/100, milli = 1/1000, a meter is a bit larger than a yard and a centimeter is about the width of your index finger.66The Size of the Earth• Eratosthenes measured the shadow of a pillar in Alexandria when the sun was directly overhead in Syene (no shadow in a well)• Geometry shows that:Earth theof radiuscitiesbetween distanceheightpillar length shadow=Note that this is one of the first recorded scientific measurements and that almost 2000 years before Columbus set sail, many people knew that the Earth was round.77Mathematics in Science• Mathematics is the language of science• This course is concerned with the concepts of physics and uses equations as “guides” to think about the concept• You will use basic mathematics in the course but the focus will be on comprehension, not computationMath is a tool for doing science and the most concise way to communicate concepts. There are no double meanings in mathematics.Much of the homework can be completed with only words.88The Scientific Method• Ask a question• Think about the question and make an educated guess at the answer (make a hypothesis)• Determine ways to test your hypothesis• Perform experiments to test your hypothesis• Make the simplest statement that accurately records the question, the hypothesis and the experimental results– Don’t infer anything; only state what was directly observedWhere do the nutrients for a plant come from?Hypothesis: the soilTest: Plant a tree in a known amount of soil and see how much of the soil is used up by the tree after it has grown.Result: Only a small percentage of the tree’s weight is missing from the soilStatement: The nutrients must come from somewhere else (the sun and water)99Facts, Theories and Law• Hypothesis – an educated guess that has not been proven factual• Fact – a statement that experts agree on• Theory – a combination of facts that together explain aspects of nature• Law – a long standing hypothesis that has been repeatedly tested and has not been contradicted Hypothesis: A tree’s nutrients come from the soilFact: The sun is roundTheory: Particle theory (how the smallest particles interact with each other)Law: Laws of thermodynamics1010Science and Religion• Many people feel that science seeks to destroy religion• While some scientists are not religious, science only considers how nature works, not why• There are many philosophical questions that science cannot answer – for every question you answer, you can always ask why; science can only take you so farWhy does the universe obey laws at all?Why are we attracted to the Earth rather than repelled by it?What is the meaning of life?Is there a God? – since God is something we cannot measure, we cannot prove or disprove the existenceTherefore, religion lies outside the scope of science.1111Science and Technology• Science seeks to gather and organize knowledge• Technology uses the knowledge gained through science to make practical applications• Technology is used by science to discover new knowledgeEmphasize that the line between technology and science is often hard to discern.1212Physics• Physics is the most basic science– Physics seeks to the uncover the most basic facts about nature; motion, forces, energy, etc.• The science of chemistry uses physics knowledge to describe how atoms and molecules behave• The science of biology uses chemistry to describe how molecules organize to form organismsThen ecology and so on… A line can be made all the way to the social