Measuring With Scientific Units. MEASUREMENT MEASUREMENT Measurement is in NUMBERS and UNITS. Most of the world uses the METRIC SYSTEM –B–Based on the

Measuring Measuring With With

Scientific Scientific UnitsUnits

MEASUREMENTMEASUREMENT

• MEASUREMENT• Measurement is in NUMBERS and

UNITS.• Most of the world uses the METRIC

SYSTEM– Based on the ‘NUMBER TEN’ – Based on the METER

1.3 Measurement1.3 Measurement

• International System of Units (SI)

– MEASUREMENTS ALWAYS HAVE A NUMBER AND A UNIT• 4m, 25s, examples??????

– Allow scientists from all over the world to understand one another’s measurements

MEASUREMENT: SYMBOLSMEASUREMENT: SYMBOLS

Base quantity Name Symbol

Length meter m

Mass gram g

Time seconds s

electric current Ampere A

temperature Celsius oC

amount of substance Mole M

luminous intensity Candela Cd


Derived Units

Quantity Unit Symbol

Area square meter m²

Volume cubic meter m³

Density kilograms per cubic meter kg/m³

Pressure pascal (kg/m•s²) Pa

Energy joule (kg•m²/s²) J

Frequency hertz (1/s) Hz

Electric charge coulomb (A•s) C

MEASUREMENT: UNITSMEASUREMENT: UNITS

• REVIEW: LENGTHMETER: distance

REVIEW: VOLUMELITER: Volume = length x width x height = cm3


WEIGHT AND MASSGRAM: mass & weight• WEIGHT depends on WHERE YOU ARE IN THE

UNIVERSE– Changes depend on GRAVITY

• Mass depends on THE NUMBER AND TYPE OF ATOMS– ALWAYS STAYS THE SAME


• TEMPERATURE AND TIMECELSIUS: temperature• TEMPERATURE measures AMOUNT OF HEAT

– WHAT IS YOUR BODY TEMPERATURE?– 98.6 degrees Fahrenheit– 37 degrees Celsius

SECONDS: time• TIME measures ORDER OF EVENTS


DENSITY• GRAMS PER VOLUME: density• Density = AMOUNT OF MASS PER

VOLUME= grams / mL= grams / cm3

= MASS / VOLUMEPURE WATER = 1g / mL

LEAD = 11g / mL

1.3 Measurement - PREFIXES1.3 Measurement - PREFIXESPrefix Symbol Factor Number Factor Word

giga G 1,000,000,000 (109) billion

mega M 1,000,000 (106) million

kilo k 1,000 (10³) thousand

hecto h 100 (10²) hundred

deca da 10 ten

Base unit m, g, L 1meter, gram,

Liter

deci d 1/10 (10ˉ¹) tenth

centi c 1/100 (10ˉ²) hundredth

milli m 1/1,000 (10ˉ³) thousandth

micro m 1/1,000,000 (10-6) millionth

MEASUREMENT: PREFIXESMEASUREMENT: PREFIXES

king hector doesn’t buy dragons costing millions

CONVERSIONSCONVERSIONS

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 m1,000 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



• 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: LENGTHREVIEW: LENGTH

• METER: distance• Divisionskm km hm hm dam dam m m dm dm cm cm

mmmm1,000 100 10 1 1/10 1/100 1,000 100 10 1 1/10 1/100

1/1,0001/1,000

Using your meter stick, show one meter, one decimeter, one centimeter, and one millimeter

REVIEW: VOLUMEREVIEW: VOLUMEVolume = length x width x height

= cm3 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.

DENSITYDENSITY


• Measurements in science are DATA.

• It is important that they are both accurate and precise.


• Precision vs. Accuracy

– Precision = exactness •(more significant digits:

1.256m stride, not 1m)

– Accuracy = closeness to actual value. •(using a quartz or atomic

watch instead of counting in your head) try it.


• SCIENTIFIC NOTATION– A way of expressing a value by

powers of 10.– Make very large and very small

numbers easier to work with.

For practice, write these numbers out in long form.

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Measuring With Scientific Units. MEASUREMENT MEASUREMENT Measurement is in NUMBERS and UNITS. Most of the world uses the METRIC SYSTEM –B–Based on the