EARTH SCIENCE PROLOGUE TOPIC I OBSERVING AND MEASURING

EARTH SCIENCE: PROLOGUE • TOPIC I - OBSERVING AND MEASURING THE ENVIRONMENT • TOPIC II - THE CHANGING ENVIRONMENT

PROLOGUE. . . THE INTRODUCTION TO EARTH SCIENCE! n OBSERVING n MEASURING n DESCRIBING CHANGES

SO HOW DO SCIENTISTS STUDY EARTH? n MAKE OBSERVATIONS n USE INSTRUMENTS n MAKE INFERENCES

WHAT’S AN INFERENCE? n n AN INTERPRETATION OF OBSERVATIONS MAKING A GUESS BASED ON INFORMATION YOU HAVE n EXAMPLE: – I SEE YOU ARE SLEEPING IN MY CLASS…YOU DID NOT SLEEP WELL LAST NIGHT ! – IS THAT TRUE?

SCIENTISTS USE CLASSIFICATION SYSTEMS n n TO ORGANIZE OBSERVATIONS AND INFORMATION BASED ON OBSERVABLE PROPERTIES AND COMMON CHARACTERISTICS n EXAMPLES: – – – CLOUDS MINERALS ROCKS HURRICANES TORNADOES RIVERS

OBSERVATIONS INVOLVE MEASUREMENTS n TYPICAL EARTH SCIENCE MEASUREMENTS – – TIME LENGTH MASS TEMPERATURE n ALWAYS HAVE A NUMBER VALUE AND A UNIT – – 365 DAYS 37 KM 799 GRAMS 15 °

SOME MEASUREMENTS ARE DERIVED n USE MATH OPERATIONS TO DERIVE THE MEASUREMENT § VOLUME = L x W x H § SPEED = LENGTH ÷ TIME (miles per hour)

MOST MEASUREMENTS HAVE SOME DEGREE OF ERROR n CALLED PERCENT ERROR PERCENT DEVIATION n SIMILAR TO A TEST GRADE n HOW MANY WRONG (ERROR) OUT OF THE NUMBER OF POSSIBLE RIGHT n ALWAYS EXPRESSED AS %

PERCENT ERROR n MEASURE THE MASS OF A ROCK YOU SAY IT’S 40 g n ACTUALLY IT’S 50 g n DIFFERENCE BETWEEN THEM ———————— x 100 ACTUAL MEASUREMENT

GRAPHING HELPS PRESENT INFORMATION n SEE RELATIONSHIPS AND CHANGES n COMPARE VARIABLES – DEPENDENT – INDEPENDENT

DENSITY: A DERIVED MEASUREMENT n THE CONCENTRATION OF MATTER n ALL SAMPLES OF THE SAME MATERIAL HAVE THE SAME DENSITY … REGARDLESS OF SIZE OR SHAPE

DENSITY = MASS ÷ VOLUME n MEASURE MASS n DETERMINE VOLUME n DO THE MATH ! ! n INCLUDE UNITS – GRAMS/CM³

HEAT AND PRESSURE CHANGE DENSITY n ADDING HEAT CAUSES MOLECULES TO EXPAND. . . THAT’S WHY WARM AIR RISES ! n PRESSURE INCREASES DENSITY…MOLECULES ARE PRESSED TOGETHER! n HEAT AND PRESSURE AFFECT THE STATE OF MATTER

SUBSTANCES ARE MOST DENSE AS SOLIDS n WATER IS THE EXCEPTION! n IT’S MOST DENSE AS A LIQUID AT 4° C n SOLID WATER FLOATS IN LIQUID WATER. . . IS THAT WEIRD?

TOPIC II – THE CHANGING ENVIRONMENT n CHANGE HAPPENS ALL THE TIME! n DESCRIBED IN TERMS OF TIME AND SPACE. . . WHEN AND WHERE! n EXAMPLES » » » WEATHER RIVERS GLACIERS MOUNTAINS OCEANS

RATE OF CHANGE. . . CHANGE IN RELATION TO TIME n n n HOW MANY DEGREES THE TEMPERATURE DROPPED IN AN HOUR HOW MANY INCHES OF SNOW FELL DURING THE NIGHT HOW MUCH EROSION HAPPENED IN ONE YEAR n EQUATION TO FIND THE RATE OF CHANGE: CHANGE IN FIELD VALUE —————— CHANGE IN TIME § “FIELD VALUE” IS THE THING THAT IS CHANGING … TEMPERATURE, SNOW, EROSION. . .

SOME CHANGES ARE CYCLIC n ORDERLY CHANGES WITH A PATTERN – – SUNRISE/SUNSET SEASONS OCEAN TIDES MOON PHASES

ALL CHANGES TAKE ENERGY! n ENERGY FLOWS FROM ONE PART OF THE ENVIRONMENT TO ANOTHER n INTERFACE - A BOUNDARY BETWEEN MATERIALS… WHERE ENERGY IS EXCHANGED

WHERE IS THE INTERFACE? WHAT’S THE SOURCE OF ENERGY? ARE THE WAVES CYCLIC?

WHAT’S THE SOURCE OF ENERGY HERE?

LET’S REVIEW. . . 10 BASIC TERMS n OBSERVATIONS n INFERENCE n n n CLASSIFICATION DEPENDENT VARIABLE DENSITY n RATE OF CHANGE n CYCLIC CHANGE ENERGY n INTERFACE PERCENT ERROR INDEPENDENT VARIABLE

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