Measuring With Scientific Units. MEASUREMENT MEASUREMENT Measurement is in NUMBERS and UNITS. Most...

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

1.3 Measurement1.3 Measurement

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

MEASUREMENT: UNITSMEASUREMENT: UNITS

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

MEASUREMENT: UNITSMEASUREMENT: UNITS

• 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

MEASUREMENT: UNITSMEASUREMENT: UNITS

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

CONVERSIONSCONVERSIONS

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

CONVERSIONSCONVERSIONS

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 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

1.3 Measurement1.3 Measurement

• Measurements in science are DATA.

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

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• 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.

1.3 Measurement1.3 Measurement

• 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.