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The Basics. Introduction to Foundations of Science. Units of Measurement. Length: The straight-line distance between any two points Mass: A measure of the quantity of matter in an object Volume: A measure of space. Weight: The force with which gravity pulls on a quantity of matter
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The Basics Introduction to Foundations of Science Presented by April Senger
Units of Measurement • Length: The straight-line distance between any two points • Mass: A measure of the quantity of matter in an object • Volume: A measure of space. • Weight: The force with which gravity pulls on a quantity of matter • A system of communication observations with labels Presented by April Senger
Measurement Facts • The le Systeme Internationale d’ Unites is abbreviated SI and is used worldwide • V, A, l, w, etc are all units & m2, m/s2 are derived units • Length is in meters, mass in grams, volume in liters, time in seconds, temperature in Kelvin, electrical current in ampere, amounts of substances in moles, and luminous intensity in candelas…m, g, s, K, A, mol, and cd Presented by April Senger
More Facts… • Prefixes to know are: • Nano n billionth .000 000 001 • Micro µ millionth .000 001 • Milli m thousandth .001 • Centi c hundredth .01 • Deci d tenth .1 • Kilo k thousand 1000 • Mega M million 1 000 000 • Giga G Billion 1 000 000 000 Presented by April Senger
Variable • Variables are anything that can change in an experiment • Things that you can change…Sometimes represented by a letter of the alphabet • The best experiments only test one variable at a time • Common variables in science are v, t, & d • There are three kinds of variables: controlled, independent, and dependent Presented by April Senger
Conversions • Using multiples to change one unit of measurement to another • Changing one measurement into another Presented by April Senger
Cool Facts • I may call this “doing conversions” or “the factor label method” • Ex: You have 15 one dollar bills. How many quarters is that worth? • Step 1: List the givens and unknowns Given: 15 dollars Unknown: ? Quarters Presented by April Senger
Example Continued… • Step 2: Determine the relationship • 1 dollar = 4 quarters • Step 3: Write down the conversion fraction • Dollars x 4 quarters • Dollars • Step 4: Insert your knowns • 15 Dollars x 4 quarters • Dollars Presented by April Senger
Exclusions • Temperature conversions are more complex and do not work with this method: • 0º C = 32º F • 37º C = 98.6º F • 100º C = 212º F Presented by April Senger
Graphs are visual means of representing data collected Independent variables always go on the x-axis Dependent variables always go on the y-axis Line graphs are best for data with changes Ex: Time (independent) and Volume (dependent) Bar graphs are best for individual data or events Ex: Melting points (dependent) and kinds of metal (independent) Pie charts are best for displaying the parts of a whole Ex: The % of gases in our atmosphere Graphing Presented by April Senger
Scientific Notation • Scientific notation is a value written as a simple number multiplied by a power of ten • Changing very large or small numbers into easier numbers to work with Presented by April Senger
Notation Facts • The Steps for solving • Step 1: List the givens and unknowns • Step 2: Write the form for Sci Notation • Step 3: Insert known values and solve • The speed of light is 300,000,000 m/s and the distance to Neptune is 4,600,000,000,000 m to Earth. To calculate the time it would take light to get there you could: Presented by April Senger
Example • t = 4,600,000,000,000 m = 4.6 x 1012 m 300,000,000 m/s 3.0 x 108 m/s • t = 1.53 x104 s • When multiplying 2 numbers you add the powers of ten • When dividing you subtract the powers of ten Presented by April Senger
Precision & Accuracy • Precision is the degree of exactness of a measurement. Accuracy is the extent to which a measurement approaches the true value • Precision is getting the exact number again and again. Accuracy is getting the right number Presented by April Senger
Cool Facts • A measurement is only as accurate as the tool used to measure it • Dart Board Ex of Precision Presented by April Senger
Continued… • Dart Board Ex of Accuracy Presented by April Senger
Significant Digits/Figures • The digits in a measurement that are known with certainty. • The number of digits we should use with confidence Presented by April Senger
Sig Figs In Action • 1.543, 13.50, 1940., and 4053 have 4 sig figs • 1.5, 57, 90., .0086, and .45 have 2 sig figs • All zeros count except place holders 480 or .04 • Rounding up and down follow these rules • 3.45 rounds to 3.4 because it is even • 3.55 rounds to 3.6 because it is odd Presented by April Senger
More Facts • When multiplying or dividing numbers you round to the smallest number of sig figs • Ex: 5.43 x 23.56 = 127.9308 = 128 • When adding or subtracting you use the smallest number of decimal places being added or subtracted • Ex: 3.456 + 45.35 = 48.806 = 48.81 Presented by April Senger