Metric System By Mr. M

NOT METRIC Foot Pound Inch Mile Gallon Fahrenheit These may NEVER be in your units

The loss of the the Mars Climate Orbiter on September 23, 1999, was a most unfortunate and highly avoidable event. The cause of the mishap has been traced to a mix-up over units. Preliminary findings indicated that one team used English units (e.g., inches, feet and pounds) while the other used metric units for maneuvers required to place the spacecraft in the proper Mars orbit. The 'root cause' of the loss of the spacecraft was the failed translation of English units into metric units. For nearly three centuries, engineers and scientists have been struggling with English units.

SI The Système International Main part of the metric system

Base Unit Base Quantity Name Symbol Time t second s Length l meter m Mass m kilogram kg Temperature T , Ө kelvin K Electric Current I ampere A Amount of Substance n mole mol (not in A Level) candela cd Luminous Intensity

What you are measuring Mass = amount of material Volume = space an object takes up Temperature = amount of average kinetic energy Density = how much is crammed into a space = mass divided by volume (grams/mL or grams/cm3) Remember that an item sinks if it is more dense than what it is sitting in, so ice floats because it is less dense than water

Mass Mass is not weight!!!!!!!!!!!!!!!! Mass is measured on a scale like weight is You have mass in space Mass is a measure of how much matter you have

In weightlessness 454 grams is still 454 grams; however, 1 pound will be zero pounds in zero gravity. What is the English unit for mass? In the English system the unit for mass is the slug. One slug sitting in Earth’s gravity has the weight of 32 pounds.

You may use any version of Grams for mass Liters for volume Celsius for temperature Seconds for time Meters for length

Based on 10

Prefix kilo- k 10 3 1000 hecto- h 10 2 100 deka- D 101 10 Unit ? 100 1 deci- d 10 -1 0.1 centi- c 10 -2 0.01 milli- m 10 -3 0.001 micro- mu 10 -6 0.000 001 nano- n 10 -9 0.000 000 001

Prefix plus root Kilogram means 1000 grams Centiliter means 0.01 liters Microsecond means 0.000001 seconds

Metric System The three prefixes that we will use the most are: kilo centi milli kilo hecto deca Base Units meter gram liter deci centi milli

Metric System 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 kilo hecto deca Base Units meter gram liter deci centi milli

Metric System Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length 1 centimeter = 10 millimeters Example not to scale 40 41 1 mm 40 41 1 cm

Metric System If you move to the left in the diagram, move the decimal to the left If you move to the right in the diagram, move the decimal to the right kilo hecto deca meter liter gram deci centi milli

Metric System Now let’s start from centimeters and convert to kilometers 400000 centimeters = 4 kilometers 400000 centimeters = 4.00000 kilometers kilo hecto deca meter liter gram deci centi milli

cubic centimeter cubic decimeter milliliter LITER 1 gram defined as the mass of one cubic centimeter of water (or one milliliter [mL] of water_. cubic centimeter cubic decimeter milliliter LITER

Density D = m/v Density is how much stuff is in one space Units g/mL or g/cm3 Less dense objects float, more dense sink Everything has a unique density so items can be identified by density Water has a density of 1 g/mL

Dimensional Analysis Set up a table where units are the same diagonally Multiply by everything up top Divide by everything in the bottom Units cancel out, seconds multiplied by grams divided by grams = seconds

Convert 0.15 meters to centimeters Starting amount equal End Amount 0.15 meters 1 centi = centimeters .01 meter 0.15 meters x 1 = 15 centimeters .01

Convert 5234 millimeters to meters Starting amount equal End Amount 5234 millimeters 0.001 m = meters mm 52.34 meters

Convert 21 grams per liter (21 g/L) to milligrams per milliliter (mg/mL) Starting amount equal equal End Amount 21 grams Liter mg 0.001g 0.001L mL = mg mL

Works with any relationship: example is inches to meters 2.54 cm in an inch 100 cm in meter Starting amount equal equal End Amount 15 inches 2.54 cm 1 inch 1 m 100 cm = 0.38 m

Scientific Notation The easy way of writing really big numbers or really small numbers Note, this does not change units

M x 10n Scientific Notation M is the coefficient 1<M<10 10 is the base n is the exponent or power of 10

Numbers less than 1 will have a negative exponent. A millionth of a second is: 0.000001 sec 1x10-6 1.0E-6 1.0x10^-6