THE METRIC or INTERNATIONAL SYSTEM of MEASUREMENT (SI) Scientists all over the world need to ‘communicate’ with each other. To do this easily, they use the same system of measurement. This ‘system’ is known as the……

THE BASIC UNIT OF THE ENTIRE SI SYSTEM IS THE METER This fundamental unit is a bit longer than a yard.

HOW TO MAKE LINEAR MEASUREMENTS USING SI UNITS

To measure SMALLER distances, the METER is divided by a factor of ‘10’: EXAMPLES: –Decimeter (dm) = 1/10 of a meter –Centimeter (cm) = 1/100 of a meter –Millimeter (mm) = 1/1000 of a meter A 3 day old tadpole is 1.2 centimeters in length.

To measure LARGER distances, the METER is multiplied by a factor of ‘10’:To measure LARGER distances, the METER is multiplied by a factor of ‘10’:EXAMPLES: –Hectometer (hm) = 100 meters –Kilometer (km) = 1000 meters

THE BASIC UNITS USED FOR MOST LINEAR MEASUREMENT ARE THESE FOUR…… MILLIMETERS - very small measurements CENTIMETERS - small measurements METERS - large measurements KILOMETERS - very large measurements

SI units should NOT be ‘MIXED’. That is, you would not write ‘1 meter 21 centimeters’. You should write ‘1.21 meters’. Also, linear measurements should be written using DECIMALS. In most linear measurements, ONE DECIMAL PLACE is sufficient. Do NOT use FRACTIONS! Do NOT use FRACTIONS!

ONE LITER To obtain a unit of VOLUME in the SI System, scientists took a empty box that measured 10 cm. by 10 cm. by 10 cm. and called this……

A LITER is now a common unit used by all of us.

A LITER is also used with the prefix ‘MILLI’. Thus we have…… a MILLILITER to measure very small volumes.

This is a ONE LITER cube. 1/1000 th of it is 1 MILLILITER. This small cube is one milliliter. This large cube is one liter.

A MILLILITER has the same volume as ONE CUBIC CENTIMETER. A MILLILITER has the same volume as ONE CUBIC CENTIMETER. Which means, milliliters (ml) and cubic centimeters (cc) can be interchanged. They both have the SAME volume! 125 cc’s

Now……to get a unit for MASS, scientists took 1 MILLILITER OF WATER and made that mass equal to 1 GRAM! 1 ml of water = 1 gram

Again, PREFIXES can be used in front of a GRAM. The common ones are…… MILLIGRAM - very small masses KILOGRAM - large masses 1 ‘carat’ equals 200 milligrams

Before we leave MASS units, we need to consider one other thing…… MASS and WEIGHT are NOT the same!

‘MASS’ is the amount of ‘stuff’ in an object. It does NOT have anything to do with GRAVITY!

MASS does NOT change ! It is measured in GRAMS. It’s the SAME everywhere in the universe. It does NOT depend on gravity. It is measured with a BALANCE. All these things’ masses stay the same, wherever they are!

WEIGHT CHANGES ! It depends on GRAVITY. It is usually measured in ‘pounds’. It is measured with a spring scale.

WEIGHT CHANGES WITH GRAVITY!

You may be ‘WEIGHTLESS’ but you still have MASS!

and finally……THERE TWO TYPES OF MEASUREMENT IN SCIENCE AN ‘UGLY’ BABY? YOU WEIGH 100 POUNDS. QUANTITATIVE QUALITATIVE

EXAMPLES: 70 degrees Celsius70 degrees Celsius One inch of rainOne inch of rain 6.2 centimeters6.2 centimeters 640 miles640 miles She scored 26 pointsShe scored 26 points 1.QUANTITATIVE

MAKING ‘QUANTATIVE’ MEASUREMENTS:

EXAMPLES: It’s nice outIt’s nice out It’s really hotIt’s really hot It’s raining cats and dogsIt’s raining cats and dogs He’s good lookingHe’s good looking 2.QUALITATIVE

Whenever possible…… QUANTITATIVE is preferred over QUALITATIVE in SCIENCE!

A QUICK SI REVIEW 1. THE BASIC SI UNIT OF LENGTH IS A _____.1. THE BASIC SI UNIT OF LENGTH IS A _____. 2. 1/100th OF A METER IS _____.2. 1/100th OF A METER IS _____. 3. THE ‘SI SYSTEM’ USED TO BE CALLED _____.3. THE ‘SI SYSTEM’ USED TO BE CALLED _____. 4. A ____ IS USED TO MEASURE VERY LARGE LINEAR DISTANCES.4. A ____ IS USED TO MEASURE VERY LARGE LINEAR DISTANCES. 5. 1/1000th OF A GRAM IS ONE _____.5. 1/1000th OF A GRAM IS ONE _____. 6. ‘AREA’ IS FOUND BY MULTIPLYING _____. TIMES THE _____.6. ‘AREA’ IS FOUND BY MULTIPLYING _____. TIMES THE _____. 7. THE BASIC SI UNIT OF MASS IS A _____.7. THE BASIC SI UNIT OF MASS IS A _____. 8. THE SMALLEST SI PREFIX USED DAILY IS THE _____.8. THE SMALLEST SI PREFIX USED DAILY IS THE _____. 9.WEIGHT CHANGES WITH ______.9.WEIGHT CHANGES WITH ______. 10.THE BASIC SI UNIT OF VOLUME IS A ______.10.THE BASIC SI UNIT OF VOLUME IS A ______.