The Metric System: Measuring Length

7th GradeEarth Science

Write Everything in Blue!!!

History

The metric system evolved over the years and in the 1960’s was named the International System of Measurement (SI for short).

Scientific standards were set with the gram, meter, kelvin, second, ampere, candela, & in 1971 – the mole

Advantages of Metric System No numbers to

memorize Only 30 individual

units Easy to say and

write

No fractions only decimals

World standard Converts easily by

multiples of 10.

Units of Measurement Prefixes and

Multiplier: Kilo = 1000 Hecto = 100 Deca = 10 Meter/Gram/Liter = 1 Deci = .1 Centi = .01 Milli = .001

Examples: Kilometer Hectometer Decameter Meter Decimeter Centimeter Millimeter

Length: The standard unit of length in the metric

system is the meter. Other units of length and their equivalents in meters are as follows: 1 millimeter = 0.001 meter1 centimeter = 0.01 meter1 decimeter = 0.1 meter1 decameter = 10 meters1 hectometer = 100 meters1 kilometer = 1000 meters

Metric Length

If you need to measure length, you use the “meter”

If you need to measure longer lengths, you can use the kilometer Lets say you live 10 miles from school▪ 10 miles = 16093 meters▪ 16093 is a large number, so you can move

the decimal 3 spots to make it 16.1 kilometers

Abbreviations:

We abbreviate these lengths as follows:1 millimeter = 1 mm1 centimeter = 1 cm1 meter = 1 m1 decimeter = 1 dm1 kilometer = 1 km

Examples:

For reference, 1 meter is a little longer than 1 yard or 3 feet. It is about half the height of a very tall adult. A centimeter is nearly the diameter of a dime, a little less than half an inch. A millimeter is about the thickness of a dime.

Who Does Not Use It?

The only countries not to use the Metric System are the U.S., Myanmar, and Liberia

English to Metric Conversions 39,370 inches = 1

kilometer 3280.8 feet = 1

kilometer .62 miles = 1

kilometer 39 inches = 1

meter 3.28 feet = 1

meter

1 inch = 254 mm 1 inch = 2.54 cm 1 foot = 30.48 cm 1 yard = 91.44 cm 1 yard = .914 m 1 mile = 1609.3 m 1 mile = 1.609 km

You do not need to know these. They are just for you to get an idea of how these systems compare.

Comparisons

Metric Measurements

The 3 main measurements are the gram (weight), meter (length), & liter (volume)

Metric Prefixes These prefixes are based on powers of 10. What does this mean?

From each prefix every “step” is either:▪ 10 times larger

or▪ 10 times smaller

For example▪ Centimeters are 10 times larger than millimeters▪ 1 centimeter = 10 millimeters

Metric Prefixes

For each “step” to right, you are multiplying by 10

For example, let’s go from a base unit to centi1 liter = 10 deciliters = 100 centiliters

2 grams = 20 decigrams = 200 centigrams

Summary

Summary Base units in the metric system are meter, liter,

gram Metric system is based on powers of 10 For conversions within the metric system, each

“step” is 1 decimal place to the right or left