Unit Conversion and the Metric System Bio Sciences: Measurements Unit Conversion and the Metric System Property of CTE Joint Venture

Objectives List three (3) common measurement systems used in high schools List common unit conversion equivalencies Use dimensional analysis to convert between units Property of CTE Joint Venture

Terminology Unit of Measurement: A definite size of some physical quantity, defined and adopted by convention, that is used as a standard for measurement of the same physical quantity. Dimensional Analysis: A problem-solving method that uses the fact that any number or expression can be multiplied by one without changing its value. Also called the Factor-Label-Method Property of CTE Joint Venture

Units of Measurement Unit of Measurement: A definite size of some physical quantity, defined and adopted by convention, that is used as a standard for measurement of the same physical quantity. Basically it is an accepted value that can be converted to other accepted values by simple multiples. List as many units of measurements as you can in 15sec and be prepared to share! Property of CTE Joint Venture

The key is to use the correct unit in a specific situations Units Can Represent… Unit of Measurement can be used to represent Mass – pounds or kilograms Volume – gallons or liters Length – inches or kilometers Temperature – Fahrenheit or Celsius Energy – Calories or Joules Time – Hours or second Velocity – miles per hour or meters per second The key is to use the correct unit in a specific situations Property of CTE Joint Venture

Systems of Measurement There are three (3) systems commonly used if high school science: The imperial system; in, gal, lbs,˚F, etc. The metric system; cm, ml, g, ˚C, etc. The SI system; m, L, kg, K, etc. We will learn how to convert with in each system and between systems (metric & imperial). The SI system will be discussed in more detail in your chemistry or physics class. Property of CTE Joint Venture

The Imperial System of Measurements and Conversions What you are most like familiar with Length Unit Conversion Equivalence in feet 12in = 1ft foot miles 5280ft =1mile Volume Unit Conversion Equivalence Fluid ounce cups 1fl.oz. =0.125 cup US cup quart 1cup US = 0.25qrt US gallon 1qrt US = 0.25gal US Mass Unit Conversion Equivalence ounce pounds 16oz =1lbs Temperature Unit Fahrenheit (˚F) Property of CTE Joint Venture

The Metric System of Measurements and Conversions It is a base 10 system – that makes it easy to use, these are the most common metric units we will see. Measurement Base Unit Mass Gram (g) Volume Liter (l) Length Meter (m) Temperate Celsius (˚C)* Useful volume relationship 1ml = 1cc (cm3) Power of 10 103 100 10-1 10-2 10-3 10-6 10-9 Abbreviation k g, l, m d c m µ n Prefix kilo- base deci- centi- milli- micro- nano- * Never gets a prefix – does not change magnitude Property of CTE Joint Venture

Some Equivalences Between Systems Metric Imperial Equivalence Volume ml or cm3 fl. oz. 1fl. oz. =26.57ml Mass g oz 1oz =26g Length cm in 1in = 2.54cm Temperature ˚C ˚F ˚C to Kelvin (K) NA K = ˚C+273 This is just a few equivalencies, there are many, many more. Property of CTE Joint Venture

Converting Units of Measurements Suppose you are given a bottle some chemical and need to weigh out 40mg of it, but your scale only reads out weight in ounces, what do you do? THINK-PAIR-SHARE You need to convert 40mg to oz., but how? Property of CTE Joint Venture

How many jumps does it take? 1 2 3 KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit Meters Liters Grams CENTI 0.01 Unit MILLI 0.001 Unit How do you use the “ladder” method? 1st – Determine your starting point. 2nd – Count the “jumps” to your ending point. 3rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m Starting Point Ending Point How many jumps does it take? 4. 1 __. 2 __. 3 __. = 4000 m

Ladder Method King Henry Died By Drinking Chocolate Milk Kilo = x1000 Basic units = Mike Likes Girls (Meters, Liters, Grams) How big am I compared to the base unit?? Kilo = x1000 Hecto = x100 Deca = x10 Deci = 1/10 Centi = 1/100 Milli = 1/1000 Property of CTE Joint Venture

How to Make Unit Conversions Easy! The most powerful tool next to your calculator and algebra skills for working with numbers is something calls Dimensional Analysis: A problem-solving method that uses the fact that any number or expression can be multiplied by one without changing its value. Also called the Factor-Label-Method If you get this down the rest of science math is easy Property of CTE Joint Venture

Dimensional Analysis: Basics ALL order of operations rules apply here and other than that this is the basic format presented. Numbers chosen so that the top is equal to the bottom. Units you want at the end Units you start with to cancel out.       = What you start with   What you will get

Closure In your notebook on the left side, write down any struggles you have with the metric system or dimensional analysis. If you do not have any, then right down some tips or tricks that have helped you understand either one. Property of CTE Joint Venture