7th Grade Integrated Science The Metric System 7th Grade Integrated Science

Metric System Why do we use it? It is used in all science and medicine It is used all over the world (except 3 countries) It is based on 10 It has small accurate units

Quick: What does the United States, Liberia and Myanmar have in common Quick: What does the United States, Liberia and Myanmar have in common? These countries do not use the metric system. True fact! The U.S. uses the “customary system”, which was developed from English units, used in the British Empire. Until the mid 1800s, the units of measurements of the UK and the US were virtually the same. But as of today, the UK uses metric system, like 99% of the world. Consider this: Back in 1999, NASA lost a $125 million Mars orbiter because one engineering team used metric units while another used the “customary units” (e.g., inches, feet and pounds) for a key spacecraft operation.  (source: NASA REPORT ) Why is the US, a global leader in so many sectors, not a member of the global system of measurements?  At some point in the 1800s, the UK decided to change its system and eventually joined the rest of the civilized world in adopting the metric system. In 1927, the US congress was bombarded by millions of people sending petitions to adopt the metric system. However, the government turned a deaf ear to its citizens and favored a lobby by the manufacturing industry, citing the cost of the conversion. I am sure that if the government decided to add up all the lost money as a result of NOT using the metric system, they would see that the cost of conversion would not be that high. Research shows that NASA alone has lost almost $1 billion dollars as a result of “failures” and “mistakes” not too different from the Mars orbiter. Mind you, Myanmar and Liberia are planning to change to the metric system. The US can not end up as THE ONLY COUNTRY NOT USING THE METRIC SYSTEM.

Metric System Base units of the Metric System Liquid or Volume= Liter (L) Length or distance = meter (m) Mass or weight= grams (g)

Metric System Metric Prefixes Kilo(k)= 1,000 (thousand) Hecto (h)= 100 (hundred) Deca (da)= 10 (ten) Deci (d)= .1 (tenth) Centi (c)= .01 (hundredth) Milli (m)= .001 (thousandth)

Examples g= gram kg= kilogram mg= milligram cg= centigram m = meter L= liter km = kilometer kL = kiloliter mm = millimeter mL= milliliter cm = centimeter cL = centiliter

MEMORIZE!!!!! 1 km= 1,000 m 1 m= 100 cm 1 m= 1,000 mm 1 cm= 10 mm 1 L= 1,000 mL 1 kg=1,000 g

Conversions Use: kilo hecto deca UNIT deci centi milli (meter, gram, King Henry Died Unusually Drinking Chocolate Milk kilo  hecto  deca   UNIT     deci  centi  milli   (meter, gram, or liter)  

TRY IT! 100cm = ___ m 6.9mm = ___cm

Answers 100cm = 1.0 m 6.9mm = .69 cm