Introduction, Scientific Method, Measurements Learning Objectives Physical Sciences Scientific Method Standard Units Fundamental and Derived Quantities Converting Units

Physical Sciences BIOLOGICAL SCIENCES PHYSICSCHEMISTRYASTRONOMYMETEOROLOGYGEOLOGY PHYSICAL SCIENCES NATURAL SCIENCESSOCIAL SCIENCES SCIENCES (Latin scientia meaning knowledge) An organized body of knowledge about the natural Universe, and the processes by which that knowledge Is acquired and tested Concerned with the basics principles of matter & energy Deals with the composition, structure, and reactions of matter. Study of the universe, which is the totality of all matter, energy, space, and time. Study of the atmosphere, from the ground in outer space. Science of the planet Earth-its composition, structure, processes, and history.

Scientific Method The part we see but do not understand The part we (think) we understand The Universe – all which is observable How can we come to understand the Universe? Epistemology: study (or philosophy) of knowledge. Ways of knowing: Fideism: acceptance of an idea, theory, or explanation only on the evidence of a “higher authority”. Religious beliefs, based on faith or revelation. Science: a systematic method of observation and experimentation. Based on “evidence” and experimental observation

Scientific Method Measurement: a quantitative observation Hypothesis: a very tentative, possible answer or an educated guess Experiment: an observation of natural phenomena carried out in a controlled manner Theory: a well-tested explanation of a broad segment of natural phenomena Scientific revolution of the 1600s was due primarily to an adoption of the scientific method by Galileo, Newton, and Boyle. Ockham’s Razor: In choosing between two seemingly valid explanations of a particular phenomenon, the simpler and more general one is preferred.

Scientific Method Limitations: –Deals only with the natural world and never invokes supernatural explanations –Does not attempt to answer questions as the purpose of the universe or life. –These questions are for philosophy and religion

Scientific Method Beware of Pseudoscience! Pseudoscience – the dogmatic and irrational belief in an appealing idea that appears scientific but that is not supported by scientific methods. * Astrology (from ancient Babylonian culture) * UFO-ology (popular culture and mistrust of government) * “structure –altered water” (commercial quackery) How can you recognize a pseudoscience? SciencePseudoscience The primary goal of science is to achieve a more complete and more unified understanding of the physical world. Pseudosciences are more likely to be driven by ideological, cultural, or commercial goals. Most scientific fields are the subjects of intense research which result in the continual expansion of knowledge in the discipline. The field has evolved very little since it was first established. The small amount of research and experimentation that is carried out is generally done more to justify the belief than to extend it. Observations or data that are not consistent with current scientific understanding, once shown to be credible, generate intense interest among scientists and stimulate additional studies Observations or data that are not consistent with established beliefs tend to be ignored or actively suppressed Scientific explanations must be stated in clear, unambiguous terms. Pseudoscientific explanations tend to be vague and ambiguous, often invoking scientific terms in dubious contexts.

Mathematical Nature of Science Newton and Leibniz  Calculus Mathematics is the only language precise enough to accurately describe the laws of nature.  isomorphism Skills needed for success in this course –Algebra –Basic Trigonometry –Graphical Analysis Do not worry about your difficulties in Mathematics. I can assure you mine are still greater. – Albert Einstein

Measurements - Units We need numbers in order to accurately take measurements When executing the scientific method we must perform experiments  measurements  data Express measurements using units (i.e. metric units, English units, etc.) Unfortunately American students must learn both systems! Units allow us to describe things numerically Measurement standards – a fixed and reproducible value for the purpose of taking accurate measurements How do we know the length of a meter, yard? Human arm, standard for length, cubit – Egyptians King Loius XIV, length of the royal foot Distance from equator to north pole Modern standard, distance light,travels in 1/299,792,458 s

The sizes of things: What does mean? What does 10 2 mean? 10 2 = 10  10 = 100 notice that the 2 tells us how many zeros there are in the answer! 10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10 = 10,000,000,000,000,000,000,000,000 What does mean? What does mean? = 0.1  0.1 = 0.01 notice that the -2 tells us how many places to the left we move the decimal point! 0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1  0.1 = This type of notation is called “scientific notation” it is used to represent very large and very small numbers in a manner that is efficient and easy to do.

Units Mass: the kilogram –One kilogram is the mass of a particular platinum- iridium cylinder kept at the International Bureau of Weights and Standards, Sèvres, France. one kilogram weighs slightly less than one kilogram

Units Time: the second –One second is the time for radiation from a cesium-133 atom to complete 9,192,631,770 oscillation cycles.

Units Fundamental units – fundamental because they are the most basic quantities or properties –Length (International System, SI  meter (m), British  foot (ft)) –Mass (SI  gram (gr), British  slug (sl)) –Time (SI & British  second (s)) Derived units – combinations of fundamental units –Speed (SI  m/s, British  ft/s) –Acceleration (SI  m/s 2, British  ft/s 2 ) –Force = mass × acceleration (SI  kg·m/s 2 = Newton (N), British  pounds (lbs)

Derived UnitQuantityMKSCGS AreaLength 2 m2m2 cm 2 VolumeLength 3 m3m3 cm 3 VelocityLength/Timem/sm/scm/s Densitymass/volume = mass/Length 3 kg/m 3 gr/cm 3 AccelerationLength/Time 2 m/s2m/s2 cm/s 2 Forcemass  Acceleration = mass  Length/Time 2 (kg  m)/s 2 (gr  cm)/s 2 PressureForce / Area = (mass  Length/Time 2 )/Length 2 [(kg  m)/s 2 ]/m 2 [(gr  cm)/s 2 ]/cm 2 Units MKS : Meter-Kilogram-Second CGS: Centimeter-Gram-Second Sometimes even the derived units are called different names because they are so cumbersome. Typically these units are named after a scientist that contributed to it’s origin. Force = mass  Acceleration = (kg  m)/s 2 = NEWTON

Converting Units of Measurement – Dimensional Analysis It is often the case that we must convert from one set of units to another. Suppose we want to convert 316 ft to its equivalent in meters Example: How many kilometers is 50,000 inches? The order that you apply the conversions makes no difference in the end! these cancel ! left with the units we want !

Converting Units of Measurement – Dimensional Analysis If I drive 10 m/s in a school zone posted 20 miles/hour, am I speeding? Here we must convert two things: meters to miles, and seconds to hours Conversions are a breeze with the metric system because it is based on powers of 10!

Converting Units of Measurement – Dimensional Analysis PrefixPowerExamples Kilo-1000, 10 3 Kilometer, Kiloliter, Kilogram Hecto-100, 10 2 Hectometer,Hectoliter,Hectogram Deca-10, 10 1 Decameter,Decaliter,Decagram m, l, gr1, 10 0 meter,liter,gram Deci-0.1, Decimeter,Deciliter,Decigram Centi-0.01, Centimeter,Centiliter,Centigram Milli-0.001, Millimeter,Milliliter,Milligram What if I had 10 milliliters and needed to convert this to kiloliters?

PrefixPowerExamples Kilo-1000, 10 3 Kilometer, Kiloliter, KilogramKind Hecto-100, 10 2 Hectometer,Hectoliter,HectogramHector Deca-10, 10 1 Decameter,Decaliter,DecagramDecked m, l, gr1, 10 0 meter,liter,gramMr. Deci-0.1, Decimeter,Deciliter,DecigramDeci Centi-0.01, Centimeter,Centiliter,CentigramCinema Milli-0.001, Millimeter,Milliliter,MilligramMonday Converting Units of Measurement – Dimensional Analysis Kind Hector Decked Mr. Deci at the Cinema on Monday. K H D M D C MEach word represents one of the powers of ten in the metric system!!

Converting Units of Measurement – Dimensional Analysis K H D M D C M So let’s look at how this works using the example we just did. What if I had 10 milliliters and needed to convert this to kiloliters? K H D M D C M 10.0 mL = ?? kL K H D M D C M Notice that I had to move over 6 letters to get to the “K” (or Kilo). So this corresponds to the number (and direction) of spaces I have to move my decimal! 10.0 mL = kL Let’s try another example!Go to H-ITT Question

Converting Units of Measurement – Dimensional Analysis We can use converting units to solve some neat problems. How about this. If I know that a stack of 1,000 - $1 bills is = 1 inch in height Could I jump over $1,000,000? Where would we start? ???

Dimensional Analysis Any valid physical formula must be dimensionally consistent – each term must have the same dimensions From the table: Distance = velocity × time Velocity = acceleration × time Energy = mass × (velocity) 2