Unit Unit Conversion Conversion

and the Metric and the Metric SystemSystem

Bio Sciences: Measurements

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ObjectivesObjectives

1. List three (3) common measurement systems used in high schools

2. List common unit conversion equivalencies

3. Use dimensional analysis to convert between units

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TerminologyTerminologyUnit 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

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Units of MeasurementUnits of MeasurementUnit 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!

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Units Can Represent…Units Can Represent…Unit of Measurement can be used to representMass – pounds or kilogramsVolume – gallons or litersLength – inches or kilometersTemperature – Fahrenheit or CelsiusEnergy – Calories or JoulesTime – Hours or secondVelocity – miles per hour or meters per second

The key is to use the correct unit in a specific situations

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Systems of MeasurementSystems of MeasurementThere 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.

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The Imperial System of The Imperial System of Measurements and ConversionsMeasurements and ConversionsWhat you are most like familiar with

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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

quart gallon 1qrt US = 0.25gal US

Mass

Unit Conversion

Equivalence

ounce

pounds 16oz =1lbs Temperature

Unit

Fahrenheit (˚F)

The Metric System of The Metric System of Measurements and ConversionsMeasurements and Conversions

It is a base 10 system – that makes it easy to use, these are the most common metric units we will see.

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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-

Measurement

Base Unit

Mass Gram (g)

Volume Liter (l)

Length Meter (m)

Temperate Celsius (˚C)*

* Never gets a prefix – does not change magnitude

Useful volume relationship

1ml = 1cc (cm3)

Some Equivalences Between Some Equivalences Between Systems Systems

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This is just a few equivalencies, there are many, many more.

Converting Units of Converting Units of MeasurementsMeasurementsSuppose 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

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You need to convert 40mg to oz., but how?

KILO1000Units

HECTO100

Units

DEKA10

UnitsDECI

0.1Unit

CENTI0.01Unit

MILLI0.001Unit

MetersLitersGrams

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

12

3

How many jumps does it take?

Starting Point Ending Point

4.1

__.2

__.3

__. = 4000 m

Ladder MethodLadder Method

Kilo = x1000Hecto = x100Deca = x10

Deci = 1/10Centi = 1/100Milli = 1/1000

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King Henry Died By Drinking Chocolate Milk

Basic units = Mike Likes Girls(Meters, Liters, Grams)

How big am I compared to the base unit??

How to Make Unit Conversions How to Make Unit Conversions Easy!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-MethodIf you get this down the rest of science math is easy

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Dimensional Analysis: BasicsALL order of operations rules apply here

and other than that this is the basic format presented.

=What you start with What you will get

Units you start withto cancel out.

Units you want at the end

Numbers chosen so that thetop is equal to the bottom.

ClosureClosureIn 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.

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