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Day 2, Thursday, 27 August, 2015 The Metric System Physics and Science The Metric System Scientific Notation Day 6, Tuesday, 31 August, 2010 Metric System Physics and Science The Metric System Scientific Notation What is Physics? Physics (Greek: φύσις (phúsis), "nature" and φυσικῆ (phusiké), "knowledge of nature") is the branch of science concerned with discovering and characterizing universal laws that govern matter, energy, space, and time. Limits of science Natural sciences deal only with what is observable or testable. Science cannot go into matters of faith Scientists and experiments are flawed. The process (over time) is self correcting. Difference between Art and Science Science agrees on some main points (theories). So progress may be judged. Freud turned Psychology into a science. Art has no point of agreement. There is no way to judge progress. Bach vs Beatles Major branches of science Chemistry Physics Biology Minor branches of science Places Relationships Geology, Oceanography, Meteorology, Astronomy Environmental Science Special interests Psychology, Anthropology, Sociology, etc. Metric System Metric System International System of units (SI) MKS Meter, Kilogram, Second CGS Centimeter, gram, second Metric Units Units (multiples of ten) Base Derived Prefixes Base Units Length Mass Time Amount Temperature Electrical current Luminosity Meter Kilogram Second Mole kelvin ampere Candela Derived Units Electrical resistance Frequency Force Energy Power Voltage ohm hertz newton joule watt volt Scientific Notation 1.234 X 5 10 3 parts to a number in scientific notation 1. The Coefficient 2. Times 10 3. The Exponent The Coefficient This is the actual number (in front) It must have one digit before the decimal point. So, it is between 1 and 10. Drop all trailing zeros (unless they were measured and therefore significant). If the number is negative (less than zero) Then the coefficient will be negative -1.23 Times ten Every number in scientific notation has “times ten” in the middle, written as X 10 The Exponent The exponent is the exponent of the “times ten” 11 X10 It tells the number of tens columns the decimal has been moved over. The exponent may be positive, or negative A positive exponent means the number has zeros behind it and is big (greater than one). A negative exponent means the number has zeros in front of and is small (a fractional number between zero and one). Big Numbers Big numbers have trailing zeroes before the decimal . 123,000,000,000. Big numbers have positive exponents. 11 10 Small Numbers Small numbers (fractional numbers between zero and one) have leading zeroes after the decimal point. .0000000000123 Small numbers have negative exponents. -11 10 Adding and Subtracting (poor way) Put in decimal form Perform the addition or subtraction Convert back to Scientific Notation The size of the number will be the larger exponent (plus or minus one) - 1.23 X 1011 4.56 X 107 123,000,000,000. 45,600,000. 122954400000. 1.229544 X 1011 Adding and Subtracting (better way) Rewrite to get the same exponent Add or subtract the coefficients - 1.23 X 1011 4.56 X 107 12,300.00 x 107 4.56 x 107 12,295.44 X 107 = 1.229544 X 1011 An interesting insight When you add or subtract in scientific notation the answer will often have the same exponent as the larger number. The answer’s exponent will never differ from the larger number exponent by more than 1. Multiplying and Dividing Multiply or divide the Coefficients normally Add exponents when multiplying Subtract exponents when dividing Multiplication (2 X 105) (4 X 103) Coefficients 2 X 4 = 8 Exponents 5 + 3 = 8 Answer 8 X 108 Division 2 X 105 4 X 103 Coefficients Exponents 2/4 = .5 5-3 = 2 Unformatted answer .5 X 102 Proper answer 5 X 101 Credits