unit 1: data analysis units of measurements. measurement is a part of daily activities examples?

Unit 1: Data Analysis

Units of Measurements

Measurement is a part of daily activities

• Examples?

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Why would scientists want a common system of

measurement?• Scientists need to report data in such a way

that it can be understood and reproduced by other scientists across the world

• 1999 Mars Orbiter (NASA lost $125 million)– mistake was made because one engineering team

used metric units while another used English units



English Units Quantity English Units

length/distanceinches (in), feet (ft),

yards (yd), miles (mi)

massounces (oz), pounds

(lb), tons (t)

volume

fluid ounce (oz), cup (c), pints (pt), liters

(l), quarts (qt), gallons (gal)

Systéme International d'Unités (1960)

• abbreviated SI units• The other name for the metric system• This system is used by scientist worldwide

SI Base Units

Quantity SI Unit Symbol

length/distance

meter m

time second s

mass kilogram kg

amount of substance

mole mol

temperature Kelvin K

Common Conversions• 1 meter = 3.281 feet• 1 kilometer = 0.6214miles• 1 kilogram = 2.205 pounds• 1 liter = 33.81 US fluid ounces

Prefixes and base units• Prefixes are added to base units to

express small or large quantities– 1 millimeter is 1/1000 of a meter or 1 m =

1000 mm– 1 kilometer is 1000 meters or 1 km =

1000 m– Which unit would you use to measure the

width of the nail on your pinky finger?– Which unit would you use to measure the

distance from San Diego to Las Vegas?

Prefix Symbol Factor Scientific Notation

Giga G 1,000,000,000 109

Mega M 1,000,000 106

kilo k 1,000 103

hecto h 100 102

deca da or dk 10 101

1

deci d 0.1 10-1

centi c .01 10-2

milli m .001 10-3

micro µ 0.000001 10-6

nano n 0.000000001 10-9

pico p 0.000000000001 10-12

Conversions:

• Convert:– 5000 milliliters (mL) to liters (L) – 0.0250 kilograms (kg) to grams (g)– 0.625 seconds (s) to milliseconds (ms)– 880 centimeters (cm) to meters (m)

Derived Units• Certain quantities cannot be

measured in base units• A unit that is formed from a

combination of units is called a derived unit:– Volume (mL or cm3), speed (m/s),

density (g/mL or g/cm3)

Volume• Volume is the space

occupied by an object or substance

• Units– solids: cm3

– liquids: mL

• *Note: 1 cm3 = 1 mL• Graduated cylinders

are often used to measure the volume of liquids



Determining Volume for Regular Solid Object

cubeV = s3 rectangle

V = l x w x h

cylinderV= hπr2

Determining the Volume of an Irregular Solid

• How would you find the volume of a rock?

• Displacement:– The amount of water goes

up is equal to the volume of the rock

Density

• Density is defined as how much matter occupies a certain amount of space

• Units– Liquids: g/mL– Solids: g/cm3

• A pure substance will always have the same density– All samples of pure aluminum have a density of

2.7 g/cm3

or D

=M

Vdensit

y=

mass

volume

• Gold (D = 19.7 g/cm3) and aluminum ( D = 2.70 g/cm3)

• Gold is more dense than aluminum• If you have a block of gold and a block of

aluminum that are the same size (volume) the gold block will be heavier

Gold

Aluminum

V = 1 cm3

M = 2.70 gV = 1 cm3

M = 19.70 g

Temperature• Temperature is a measure of the

particle energy in a substance• The Fahrenheit scale is used in the

United States, but nearly all other countries use the Celsius scale– Celsius scale based on the freezing point

(0C) and boiling point (100C) of water• Scientists prefer the Kelvin scale

because 0 K represents absolute zero, the coldest possible temperature

Lord Kelvin• The Kelvin (K) is the SI unit for

temperature• To convert between Kelvins

and oC – K to oC : temperature in Kelvins -

273•288 K - 273 = 15oC

– oC to K : temperature in oC + 273•23oC + 273 = 296 K

unit 1: data analysis units of measurements. measurement is a part of daily activities examples?

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