Measurements and Units

Measurements and Units

Long Ago…Parts of the human body were often used to measure. The length of the king’s foot or the distance from the tip of his nose to his fingertips were both common units of measurement.

Problems• It would often change as soon as a new king

was crowned• It was different from country to country

Which is a basketful?

SI system

• (metric system) – a standard unit of measurement

All scientists everywhere can share and replicate the same data. Now used in nearly every country in the world except the United States.

1790

Metric System throughout the World

Gray – countries that only use the metric systemRed – countries that don’t use the metric system (U.S., Liberia, Burma)

What is the Metric System?

• There is only one base unit for each thing measured

Length = meterMass = gramVolume = liter

Measuring LengthEnglish System Metric Systeminch, foot, yard, mile meter

Whether you are measuring the length of your finger or the length of the Nile River, you always use meter.

Measuring Mass or WeightEnglish System Metric Systemounce, pound, ton gram

Whether you are measuring the mass of a nickelor the mass of a car, you always use gram.

Measuring VolumeEnglish System Metric System

teaspoon, tablespoon, cup, pint, quart, gallon

liter

Whether you are measuring the volume of a glass of water or the volume of a swimming pool, you always use liter.

Compare the differenceEnglish System Metric System

teaspoon, tablespoon, cup, pint, quart, gallon

liter

ounce, pound, ton graminch, foot, yard, mile meter

13 words 3 words

How big are they?

• METER – a little longer than a yard (1.1 yards)

• LITER – a little larger than a quart (1.06 quarts)

• GRAM – about the mass of a paper clip

What about measuring really big or really small things?

• In the English system, we would use inches• But in the metric system, since the meter

measures everything, it is broken up into smaller units and prefixes are added to the word “meter.”

Measured in multiples of 10

• Prefix - represent the multiples of 10

decimeter“deci” = .1 or 1/10

centimeter“cent” = .01 or 1/100

6 common prefixes:Prefix Symbol Factor NumberKilo- k 1,000

Hecto- h 100Deka- da 10

Basic Unit of Measurement (grams, liters, meters)Deci- d 0.1Centi- c 0.01Milli- m 0.001

Kilo-• Symbol = k• Number = 1000

kilometer kiloliter kilogram

1000 meters 1000 liters 1000 grams

Hecto-• Symbol = h• Number = 100

hectometer hectoliter hectogram

100 meters 100 liters 100 grams

Deka-• Symbol = da• Number = 10

dekameter dekaliter dekagram

10 meters 10 liters 10 grams

Meter, Liter, Gram• Symbol = m, l, g• Number = 1

meter liter gram

length volume mass or weight

Putting the 2 symbols together

• Kilometer = km• Hectogram = hg• Kiloliter = kl

Kilo = k meter = m

Deci-• Symbol = d• Number = .1 (tenth)

decimeter deciliter decigram

.1 meter .1 liter .1 gram

Centi-• Symbol = c• Number = .01 (hundreth)

centimeter centiliter centigram

.01 meter .01 liter .01 gram

Milli-• Symbol = m• Number = .001 (thousanth)

millimeter milliliter milligram

.001 meter .001 liter .001 gram

6 common prefixes:Prefix Symbol Factor Number Factor Word

Kilo- k 1,000 Thousand

Hecto- h 100 Hundred

Deka- da 10 Ten

Basic Unit of Measurement (grams, liters, meters)

Deci- d 0.1 Tenth

Centi- c 0.01 Hundredth

Milli- m 0.001 Thousandth

Practice• If I give you the symbol, you give me the prefix

h = c = d =

m =

da =k =

Practice• If I give you the prefix, you give me the number

kilo = deka = milli =

hecto =

deci =centi =

Practice• If I give you the symbols, you give me the word

mg = hm = dal =

cl =

km =dg=

Practice• If I give you the prefix, you give me the symbol

deka = milli = hecto =

kilo =

centi =deci =

Practice• What is the base unit for length?

• What is the base unit for mass or weight?

• What is the base unit for volume?

Even if you live in the U.S., you're using the metric system—probably without realizing it.

Your home computer might have several megabytes of memory and a few gigabytes of storage. Mega- and giga- are prefixes used in

the metric system. Mega- stands for "one million," so a megabyte is a million bytes. Giga- stands for "one billion." If computing

continues at the rate it's been going, we may soon be talking about petabytes—one million

billion bytes.

About 15 years ago, Congress passed a law saying that all consumer

products had to include both English and metric measurements