International system-units (Science 6)
- 1. INTERNATIONAL SYSTEM OF UNITS (SI)
- 2. INTERNATIONAL SYSTEM OF UNIT (SI) • Acronym SI came from Systeme Internationale d’Unites, which is the direct translation of “International System of Units” in French. • SI is based on the metric system and is the most widely used systems of measurements. • Standard SI units, which are based on the M-K-S (meter, kilogram, second), where formalized and published in 1960.
- 3. INTERNATIONAL SYSTEM OF UNIT (SI) • Acronym SI came from Systeme Internationale d’Unites, which is the direct translation of “International System of Units” in French. • SI is based on the metric system and is the most widely used systems of measurements. • Standard SI units, which are based on the M-K-S (meter, kilogram, second), where formalized and published in 1960.
- 4. INTERNATIONAL SYSTEM OF UNIT (SI) • But even as early as the French Revolution, a system of measurements for mass and length, which made use of the kilogram and the meter, respectively, was already in place.
- 5. INTERNATIONAL SYSTEM OF UNIT (SI) • Other SI Units have consequently been derived from the properties of natural objects such as water. • A litter of water weighs 1 kilogram (kg) and measures 1 cubic decimeter (dm3). The Celsius temperature scale ranges from 0ᴼC (at which point water freezes) to 100ᴼC (at which point water boils).
- 6. SI BASE UNITS • Are units of measurements defined by agreement among scientist all over the world.
- 7. SI BASE UNITS • For example, the standard meter used to be the length of a platinum-iridium alloy bar (90% platinum and 10% iridium) at melting point of ice. • Exact replicates of this length were distributed to different universities and research institutions all over the world. • However, the bars soon became distorted in different ways and thus, scientist redefined meter in terms of the distance traveled by light in a vacuum in a very small friction of a second.
- 8. SI BASE UNITS The difference in the standard length of a meter stick is negligible. However, for scientist who are who are doing research and engineers who are developing technology that need high accuracy, exact and uniform standard units of measurements are very important.
- 9. SI BASE UNITS TABLE 7.1 UNIT UNIT SYMBOL QUANTITY METER m LENGTH KILOGRAM kg MASS SECOND s TIME AMPERE A ELECTRIC CURRENT KELVIN K THERMODYNAMIC TEMPERATURE MOLE mol AMOUNT OF SUBSTANCE CANDELA cd LUMINOUS INTENSITY
- 10. INTERNATIONAL SYSTEM OF UNIT (SI) • Table 7.1 provides the base units in SI, their symbol, and the quantities they measure. • NOTE! Kelvin and degree Celsius have the same scale. It means, a one-unit increase or decrease in temperature reported in degree Celsius is the same one-unit decrease or increase in kelvin. • If you have a temperature expressed in degree Celsius and intend to express it in kelvin, all you need to is to add 273. • E.g.: the equivalent of 27ᴼC in kelvin is 300 K (27+273=300)
- 11. SI DERIVED UNITS • SI DERIVED UNITS are those units not defined by consensus among scientist around the world. These units have acquired their definitions bases on the nature of the quantity they measure in relation to one of the base quantities
- 12. SI DERIVED UNITS Length (meter) Area (m2) Length (meter) Volume (m3) height(meter) Length (meter)
- 13. SI DERIVED UNITS • Square meters (m2) and cubic meters (m3) are derived units for area and volume, respectively. The units m2 and m3 are not defined in terms of the meter. • These derived units are simply measurements in meters multiplies twice and thrice, respectively • Given that a meter denotes a universally agreed standard, m2 and m3 , in turn, have become standardized.
- 14. Other Derived Units Derived Units Area square meter m2 Volume cubic meter m3 Speed and velocity meters per second m/s acceleration meter per scond squared m/s2
- 15. SI DERIVED UNITS Express the following degree celsius in kelvin and kelvin to degree celsius 1. 29℃ 2. 31℃ 3. 44℃ 4. 64℃ 5. 101℃ 6. 301K 7. 374K 8.339K 9. 401K 10. 351K
- 16. SI DERIVED UNITS Express the following degree celsius in kelvin and kelvin to degree celsius 1. 29℃= 302K 2. 31℃ = 304K 3. 44℃ = 317K 4. 64℃ = 337K 5. 101℃ = 374K 6. 301K = 28℃ 7. 374K = 101℃ 8.339K = 66℃ 9. 401K = 128℃ 10. 351K = 78℃
- 17. SI DERIVED UNITS November 5, 2019 Science 5 Exit Ticket Memorize and Recite the units and its quantity given from table 7.1 page 208 of your book. (15 points)