Standards Of Measurement

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This PowerPoint introduces students to basic principles and rules of the International System of Measurement.

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Standards Of Measurement

  1. 1. Standards of Measurement The International System of Units (SI)
  2. 2. Units and Standards <ul><li>In order for a measurement to be useful, a measurement standard must be used. </li></ul><ul><li>A standard is an exact quantity that people agree to use for comparison. </li></ul>
  3. 3. Measurement Systems Suppose the length of a string in a ball of yarn is 100. Can you tell how much string is in the ball? NO!! <ul><li>It could be 150 feet, 150 meters, or some unit you’ve never heard of. </li></ul><ul><li>In order for a measurement to make sense it must have a number and a unit . </li></ul>
  4. 4. International System of Units <ul><li>In the U.S. we buy milk by the gallon, potatoes by the pound, and lumber by the foot. </li></ul><ul><li>These are a part of the English system of measurement. </li></ul><ul><li>Most other nations use a system of measurement based on multiples of ten. </li></ul><ul><li>This is known as the International System of Units or SI . </li></ul>
  5. 5. Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- k 1000 Deci- d 0.1 Centi- c 0.01 Milli- m 0.001 Micro- m 0.000001 Nano- n 0.000000001
  6. 6. Using SI Units <ul><li>Every type of quantity measured in SI has a base unit and a symbol for that unit. </li></ul>
  7. 7. SI Base Units Quantity Measured Unit Symbol Length Meter m Mass Kilogram kg Time Second s Electric current Ampere A Temperature Kelvin K Amount of substance Mole mol Intensity of light Candela cd
  8. 8. Length <ul><li>The SI base unit for length is the meter (m). </li></ul><ul><li>Remember: SI is based on powers of ten </li></ul><ul><li>Therefore: </li></ul><ul><li>1m=10dm=100cm=1000mm </li></ul><ul><li>Metric rulers and meter sticks are used to measure length. </li></ul>
  9. 9. Choosing a Unit <ul><li>The size of the unit you use to measure with will depend on the size of the item being measured. </li></ul>1 meter 1 centimeter 10 football fields= 1 kilometer
  10. 10. Volume <ul><li>The amount of space occupied by an object. </li></ul><ul><li>Volume= length x width x height </li></ul><ul><li>V= 3cm x 3cm x3cm </li></ul><ul><li>V= 27cm </li></ul>3 cm 3 cm 3cm 3
  11. 11. Mass <ul><li>Measurement of the matter in an object. </li></ul><ul><li>Base unit: kilograms (kg) </li></ul><ul><li>Grams (g) and milligrams (mg) are used for measuring objects of small mass. </li></ul>Which ball has more mass? How many grams are in one kilogram?
  12. 12. Density <ul><li>Density is the mass per unit of volume of a material. (Expressed as grams per cubic cm) </li></ul><ul><li>D=m/v </li></ul><ul><li>A cube of silver would be more dense than a cube of aluminum, even if they were the same size!! </li></ul>
  13. 13. Time and Temperature <ul><li>The SI unit for time is the second (s). </li></ul><ul><li>The SI unit for temperature is the Kelvin (K). </li></ul><ul><li>0 degrees K is the COLDEST possible temperature, also known as absolute zero . </li></ul>That is -273 degrees Celsius, which is 273 degrees below freezing!!
  14. 14. Summary <ul><li>A standard is an exact quantity that people agree to use for comparison. </li></ul><ul><li>In order for a measurement to make sense it must have a number and a unit . </li></ul><ul><li>The International System of Units or SI is a system of measurement based on units of 10 and used by most nations around the world. </li></ul><ul><li>Every type of quantity measured in SI has a base unit and a symbol for that unit. </li></ul><ul><li>The SI base unit for length is the meter (m). </li></ul><ul><li>The size of the unit you use to measure with will depend on the size of the item being measured. </li></ul><ul><li>Volume= length x width x height </li></ul><ul><li>Mass is the measurement of the matter in an object (kg). </li></ul><ul><li>Density is the mass per unit of volume of a material. (Expressed as grams per cubic cm) </li></ul><ul><li>The SI unit for time is the second (s). </li></ul><ul><li>The SI unit for temperature is the Kelvin (K). </li></ul>

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