# In Science and Medicine, We use the Metric System!

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In Science and Medicine, We use the Metric System!

Dimensions Unit of length: meter Unit of mass: gram
Unit of volume: liter

SI Base Units of Measurement
Mass = the gram; g 1 gram ≈ 1/28 ounce Length = the meter; m 1 meter ≈ yard Volume = the liter; l defined as 1000 cubic centimeters 1 liter ≈ quart Temperature = degrees Celsius; oC

Prefixes The metric system uses prefixes to represent units
smaller and larger than the fundamental unit by factors of 10. For example, a centimeter is 1/100 of a meter, and a kilometer is 1000 times a meter For very large numbers, we use the powers-of-ten notation, e.g. 102 = 100, 106 = 1,000,000, 10-2 = 0.01

Prefixes One of the clever ideas behind the system was to use only multiples of ten.

Converting Between Metric Units
To convert from a LARGER unit of measure to a SMALLER unit of measure, MULTIPLY by the “order-of-magnitude difference” between the units. Example: 1.2 mg = ______ g 1 mg = 1000 g 1.2 mg = 1.2 x 1000 g = 1200 g Remember to check if your answer is logical. It should take a GREATER NUMBER of SMALL UNITS to equate to a LESSER NUMBER of LARGE UNITS. A microgram is smaller than a milligram (by a factor of 1000), so a given number of milligrams should be equal to many more micrograms (1000 times as many).

Converting Between Metric Units
To convert from a SMALLER unit of measure to a LARGER unit of measure, DIVIDE by the “order-of-magnitude difference” between the units. Example: 250 ml = ______ l 1 l = 1000 ml 250 ml = 250 ÷ 1000 l = 0.25 l Is your answer is logical? It should take a LESSER NUMBER of LARGE UNITS to equate to a GREATER NUMBER of SMALL UNITS. A liter is larger than a milliliter (by a factor of 1000), so a given number of milliliters should be equal to fewer liters (1/1000 as many).

Thinking in Metric Units of Length
1 kilometer = ~0.62 or ~5/8 mi 1 meter = 1.09 yard = 39.4 in 1 centimeter = ~4/10 inch 1 angstrom = 1/10 nm or 10-10m 1 mile = ~1.6 km 1 yard = ~0.91 m 1 foot ~30.5 cm 1 inch = ~2.54 cm

Thinking in Metric Units of Volume
1 liter = ~1.06 quart 1 milliliter = 1 cubic cm (1cc) ~"a thimble full" Examples 1 teaspoon ≈ 5ml 12 oz. soda ≈ 360 ml 2-liter bottle of soda 1 gallon = ~3.8 l 1 quart = ~0.95 l 1 pint = ~0.47 l 1 cup = ~240 ml 1 fluid oz. ~30 ml 2 liters~1/2 gal.

Thinking in Metric Units of Mass
1 kilogram = 2.2 pounds 1 gram = ~"a thimble full" of water Examples 70 kg human = 154 lbs. 1 ml of water weighs ~1 g 1 pound = 454 g 1 ounce = ~28 g

Estimate The length of: The volume of: The mass of: your bare foot
your driveway The volume of: a coffee cup a bottle of shampoo The mass of: a steak a dog

Celsius: The Metric Temperature Scale
Also called the centigrade scale. Definitions 0 Celsius = 32 Fahrenheit = water freezes 100 Celsius = 212 Fahrenheit = water boils Therefore, 1C = 1.8F Conversions  Celsius = 5/9 x ( Fahrenheit - 32)  Fahrenheit = (9/5 x  Celsius) + 32 100C 212F 0C 32F

Thinking in Celsius -10 Celsius = frigid (14 F)
0 Celsius = cold (32 F) 10 Celsius = cool (50 F) 20 Celsius = comfortably warm (68 F) 30 Celsius = hot (86 F) 40 Celsius = very hot (104 F) What would you wear outside in tempsf: 10C, 0C, 10C, 20C, 30C?

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