Measurements

Measurement You are making a measurement when you Check you weight Read your watch Take your temperature Weigh a cantaloupe What kinds of measurements did you make today?

What is a Measurement? Measurement: a comparison of an the dimension of object or substance to a known standard. Dimension: a physical property of an object, any measureable property of an object Standard: a known quantity that is universally accepted Tool: an artificial object used to aid the senses in determining known standards for measurements

Standards of Measurement When we measure, we use a measuring tool to compare some dimension of an object to a standard.

Some Tools for Measurement

Solution From the previous slide, state the tool (s) you would use to measure A. temperature thermometer B. volume measuring cup, graduated cylinder C. time watch D. weight scale

In every measurement there is a Unit from measuring device Stating a Measurement In every measurement there is a Number followed by a Unit from measuring device

What Universal System Do We Use? SI- Systeme Internationale Metric System- a system of measurement based on multiples or divisions of of 10 Why? It is convenient It is universally used amongst scientists, doctors, mathematicians, etc.

Metric System The metric system is based on a base unit that corresponds to a certain kind of measurement Length = meter Volume = liter Weight (Mass) = gram Prefixes plus base units make up the metric system Example: Centi + meter = Centimeter Kilo + liter = Kiloliter

The Metric System The metric system is a measurement system based on our decimal (base 10) number system. Other countries and all scientists and engineers use the metric system for measurement.

Common Dimensions and Their Given Units of Measure Base Unit Mass Kilogram Volume Liter Time Seconds Temperature Kelvin Length Meter

What is the Length? We can see the markings between 1.6-1.7cm We can’t see the markings between the .6-.7 We must guess between .6 & .7 We record 1.67 cm as our measurement The last digit an 7 was our guess...stop there

Learning Check What is the length of the wooden stick? 1) 4.5 cm

Meters One centimeter is about the width of a large paper clip or your fingernail.

Meters A meter is about the width of a doorway

Gram Grams are used to measure mass or the weight of an object.

Grams A milligram weighs about as much as a grain of salt.

Liters Liters measure liquids or capacity. 2 Liter Soda

Liter 1 milliliter is about the amount of one drop

Changing Metric Units To change from one unit to another in the metric system you simply multiply or divide by a power of 10.

Metric System So if you needed to measure length you would choose meter as your base unit Length of a tree branch 1.5 meters Length of a room 5 meters Length of a ball of twine stretched out 25 meters

Metric System But what if you need to measure a longer distance, like from your house to school? Let’s say you live approximately 10 miles from school 10 miles = 16093 meters 16093 is a big number, but what if you could add a prefix onto the base unit to make it easier to manage: 16093 meters = 16.093 kilometers (or 16.1 if rounded to 1 decimal place)

Metric Prefixes Prefix Symbol Factor Number Factor Word Kilo- k 1000 Metric Units The metric system has prefix modifiers that are multiples of 10. Prefix Symbol Factor Number Factor Word Kilo- k 1000 Thousand Hecto- h 100 Hundred Deca- da or dk 10 Ten Unit m, l, or g 1 One Deci- d .1 Tenth Centi- c .01 Hundredth Milli- m .001 thousandth

To change from a larger unit to a smaller unit, you need to multiply. 1 km x 1000 = 1000 m 1 m x 100 = 100 cm 1 cm x 10 = 10mm

To change from smaller units to larger units you divide by a power of ten. 1000mm ÷ 10 = 100cm 100cm ÷ 10 = 10dm 10dm ÷ 10 = 1m

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 For each “step” to right, you are multiplying by 10 For example, let’s go from a base unit to centi 1 liter = 10 deciliters = 100 centiliters 2 grams = 20 decigrams = 200 centigrams ( 1 x 10 = 10) = (10 x 10 = 100) (2 x 10 = 20) = (20 x 10 = 200) kilo hecto deca meter liter gram deci centi milli

Metric System Now let’s try our previous example from meters to kilometers: 16093 meters = 1609.3 decameters = 160.93 hectometers = 16.093 kilometers So for every “step” from the base unit to kilo, we moved the decimal 1 place to the left (the same direction as in the diagram below) kilo hecto deca meter liter gram deci centi milli

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 Summary Base units in the metric system are meter, liter, gram Metric system is based on powers of 10 For conversions within the metric system, each “step” is 1 decimal place to the right or left Using the diagram below, converting to the right, moves the decimal to the right and vice versa kilo hecto deca meter liter gram deci centi milli

Place Values of Metric Prefixes Thousand Hundred Ten One Tenth Hundredth Thousandth km kg kL hm hg hL dkm dkg dkL m g L dm dg dL cm cg cL mm mg mL

Place Values of Metric Prefixes Move the decimal point to the right to multiply. Thousand Hundred Ten One Tenth Hundredth Thousandth km kL kg hm hL hg dkm dkL dkg m L g dm dL dg cm cL cg mm mL mg

Place Values of Metric Prefixes Thousand Hundred Ten One Tenth Hundredth Thousandth km kg kL hm hg hL dkm dkg dkL m g L dm dg dL cm cg cL mm mg mL

Place Values of Metric Prefixes Move the decimal point to the left to divide. Thousand Hundred Ten One Tenth Hundredth Thousandth km kL kg hm hL hg dkm dkL dkg m L g dm dL dg cm cL cg mm mL mg

Place Values of Metric Prefixes km kg kL hm hg hL dkm dkg dkL m g L dm dg dL cm cg cL mm mg mL 3km 30hm 300dkm 3000m 4L 30000dm 300000cm 12cm 3000000mm

Accuracy and Precision