Measuring With Scientific Units

MEASUREMENT MEASUREMENT Measurement is in NUMBERS and UNITS. Most of the world uses the METRIC SYSTEM –B–Based on the ‘NUMBER TEN’ –B–Based on the METER

1.3 Measurement International System of Units (SI) –M–MEASUREMENTS ALWAYS HAVE A NUMBER AND A UNIT 4m, 25s, examples?????? –A–Allow scientists from all over the world to understand one another’s measurements

MEASUREMENT: SYMBOLS Base quantityNameSymbol Lengthmeterm Massgramg Timesecondss electric currentAmpereA temperature Celsius oCoC amount of substanceMoleM luminous intensityCandelaCd

1.3 Measurement Derived Units QuantityUnitSymbol Areasquare meterm² Volumecubic meterm³ Densitykilograms per cubic meterkg/m³ Pressurepascal (kg/ms²)Pa Energyjoule (kgm²/s²)J Frequencyhertz (1/s)Hz Electric chargecoulomb (As)C

MEASUREMENT: UNITS REVIEW: LENGTH METER: distance REVIEW: VOLUME LITER: Volume = length x width x height = cm 3

WEIGHT AND MASS GRAM: mass & weight WEIGHT depends on WHERE YOU ARE IN THE UNIVERSE –C–Changes depend on GRAVITY Mass depends on THE NUMBER AND TYPE OF ATOMS –A–ALWAYS STAYS THE SAME

TEMPERATURE AND TIME CELSIUS: temperature TEMPERATURE measures AMOUNT OF HEAT –W–WHAT IS YOUR BODY TEMPERATURE? –9–98.6 degrees Fahrenheit –3–37 degrees Celsius SECONDS: time TIME measures ORDER OF EVENTS

DENSITY GRAMS PER VOLUME: density Density = AMOUNT OF MASS PER VOLUME = grams / mL = grams / cm 3 = MASS / VOLUME PURE WATER = 1g / mL LEAD = 11g / mL

1.3 Measurement - PREFIXES PrefixSymbolFactor NumberFactor Word gigaG1,000,000,000 (10 9 )billion megaM1,000,000 (10 6 )million kilok1,000 (10 ³ )thousand hectoh100 (10 ² )hundred decada10ten Base unitm, g, L1meter, gram, Liter decid1/10 (10 ˉ¹) tenth centic1/100 (10 ˉ² )hundredth millim1/1,000 (10 ˉ³ )thousandth microm1/1,000,000 (10 -6 )millionth

MEASUREMENT: PREFIXES king hector doesn’t buy dragons costing millions

CONVERSIONS Conversions are easy because they’re BASED ON THE NUMBER TEN Just MOVE THE DECIMAL! Setting up the Divisions k  h  da  base  d  c  m 1,000 units 100 units 10 units 1 unit 1/10 unit 1/100 unit 1/1,000 unit

CONVERSIONS k  h  da  base  d  c  m 1,000 units 100 units 10 units 1 unit 1/10 unit 1/100 unit 1/1,000 unit If you’re going from SMALL amounts to LARGE amounts, move the decimal TO THE LEFT 300 centimeters = 3.00 meter 56 liters = ______ kiloliters?.056 kL 82.3 milligrams = _______ decigrams?.823 dg

CONVERSIONS k  h  da  base  d  c  m 1,000 units 100 units 10 units 1 unit 1/10 unit 1/100 unit 1/1,000 unit If you’re going from LARGE amounts to SMALL amounts, move the decimal TO THE RIGHT 95 grams = 95,000 milligrams 20.5 decameters = _________ meters? 205 m 6.82 liters =.0682 cL centiliters? Good job!682 cL

REVIEW: LENGTH METER: distance Divisions km  hm  dam  m  dm  cm  mm 1, /10 1/100 1/1,000 Using your meter stick, show one meter, one decimeter, one centimeter, and one millimeter

REVIEW: VOLUME Volume = length x width x height = cm 3 or milliliters Using your graduated cylinder, show one milliliter, one centiliter, AND one deciliter

Compare the density of the same sized objects on your desk. DENSITY

1.3 Measurement Measurements in science are DATA. It is important that they are both accurate and precise.

Precision vs. Accuracy –P–Precision = exactness (more significant digits: 1.256m stride, not 1m) –A–Accuracy = closeness to actual value. (using a quartz or atomic watch instead of counting in your head) try it.

SCIENTIFIC NOTATION –A–A way of expressing a value by powers of 10. –M–Make very large and very small numbers easier to work with.

For practice, write these numbers out in long form.