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1.3 Measurement

What do the following things have in common?

•Reed

•Furlong

•Hundredweight

•Votmel

•Hand

•Palm

•Ell

1.3 Measurement

Ancient Units of Measure

•Reed: 9½ feet (approx).

•Furlong: 220 yards. 40 rods. 10 chains.

•Hundredweight: 8 stones or 112 pounds.

•Votmel: About 70 pounds of lead.

•Hand:

– 4 inches. Width of man's hand; used for height of horse

at its withers (shoulders).

•Palm: 3 inches. Width of man's palm.

•Ell: 3 feet 9 inches. Measurement of cloth.

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1.3 Measurement

What are some problems with these measurements?

•English & USA mile:

– 5280 feet. 1760 yards. 8 furlongs. 80 chains. Changed

from 5000 feet during the reign of Queen Elizabeth I.

•Scottish mile:

– 5952 feet. 1984 yards. Old measure.

•Irish mile:

– 6720 feet. 2240 yards. Old measure. Beware when told

that an Irish distance is "a mile and a bit." The bit may

be longer than the mile!

1.3 Measurement

Scientists use a set of measuring units

called SI, or the International System of

Units.

• SI is an abbreviation for Système International

d’Unités.

• SI is a revised version of the metric system,

originally developed in France in 1791.

• Scientists around the world use the same

system of measurements so that they can

readily interpret one another’s measurements.

SI Units of Measurement

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1.3 Measurement

Base Units and Derived Units

SI is built upon seven metric units, known as

base units.

• In SI, the base unit for length, or the straight-

line distance between two points, is the meter

(m).

• The base unit for mass, or the quantity of matter

in an object or sample, is the kilogram (kg).

SI Units of Measurement

1.3 Measurement

Seven metric base units make up the

foundation of SI.

SI Units of Measurement

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1.3 Measurement

Additional SI units, called derived units,

are made from combinations of base

units.

• Volume is the amount of space taken up

by an object.

• Density is the ratio of an object’s mass to

its volume:

SI Units of Measurement

1.3 Measurement

Specific combinations of SI base units yield

derived units.

SI Units of Measurement

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1.3 Measurement

Metric Prefixes

The metric unit is not always a convenient one to

use. A metric prefix indicates how many times a unit

should be multiplied or divided by 10.

SI Units of Measurement

1.3 Measurement

King Henry died drinking chocolate milk.

unit unit unit gram, meter,

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1.3 Measurement

The Scale of the World

http://www.sc.doe.gov/bes/scale_of_things.html

Ant

~ 5 mm

Red blood cells

(~7-8 µm)

1 µµµµm = 1,000 nm 1 mm = 1,000,000 nm

1 nm

DNA

~2-1/2 nm diameter Human hair

~ 60-120 µm wide

1.3 Measurement

Quiz• Quiz next class on

King Henry died drinking chocolate milk.

unit unit unit

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1.3 Measurement

Your Quiz Will look exactly like this:

milli

centi

deci

___Unit___

Deka

Hecto

Kilo

SymbolPrefixFactor

1.3 Measurement

Activity