Systeme’ Internationale: The International System of Measurement

1. Systeme’ Internationale: The International System of Measurement

2. Measurement and Mathematics is how we explore nature.

4. All types of engineering harness math and measures into practical or utilitarian endeavors.

5. With all of these meaningful measures, it is obviously very important that they are correct. There are two areas of concern: Accuracy- degree of closeness Precision – repeatability or reproducibility

6. Imagine if these types of inconsistencies found their way into some of our most important calculations. .049 pennies/transaction 150,000 transactions/day 365 days/year

8. Seven Base Measures of SI These measures are all based on physical objects or physical descriptions of reliable universal properties. meter(m) kilogram(kg) second(s) ampere(A) kelvin(K) mole(mol) candela(cd)

9. m - distance "the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 of a second."

10. kg - mass IPK prototype The kilogram is based on a platinum-iridium bar that is kept in Paris France. In its conception, the kilogram was intended to be the mass of one liter of water.

11. s - time Originally, seconds were based on the solar day, but then we learned that it was not constant. Now, the second is based on the radioactive decay of the Cesium- 133 isotope. (atomic clock)

12. A – electric current “a measure of the amount of electric charge passing a point in an electric circuit per unit time, with 6.241×1018 electrons (or one coulomb) per second.”

13. K - temperature The Kelvin temperature scale is based on absolute zero. Researchers have been attempting to reach absolute zero for many years. This figure is considered to be the lowest temperature possible. It is the temperature where all atomic motion stops.

14. The lowest naturally occurring temperature ever recorded was measured in outer space(COBE). This temperature is thought to be the lowest possible temperature attainable due to cosmic background radiation that is a remnant of the Big Bang…but I digress. 2.73 K Antarctica 184 K 38 K Triton

15. mol – actual number of atoms in an object Avogadro’s number 6.02214179 x 1023 The mol is based on the number of elementary particles that exist in 12 grams of Carbon-12.

16. cd – intensity of light This base measure has been related to: -the light of a burning candle -the filament of an incandescent light bulb -black bodies(perfect radiator of energy) and freezing platinum at 1 atmosphere. It is now defined as the intensity of light at a frequency of 540 THz with a power of 18.3988 milliwatts over a complete sphere centered at the light source.

17. Derived Measures in SI These measures are combinations of the seven base measures. Of the 22, here are a few that receive more common use in the High School classroom. Hertz(Hz) = /s= s-1 Newton(N) = kg·(m/s2) =kg·m·s-2 Pascal(Pa) = N/m2 = kg·m-1·s-2 Joule(J) = N·m = kg·m2·s-2 Watt(W) = W =kg·m2·s-3

18. Hz – measure events that happen in a definite cycle Many modern appliances operate at frequencies measured in hertz. (computers, televisions, phones, radio, remote controls, etc…)

19. N – measure of force F = ma A force of one newton will accelerate a mass of one kilogram at the rate of one meter per second per second

20. J - work James Prescott Joule actually Pronounced his name “jowl”. It is the work done by a force of one newton acting to move an object through a distance of one meter.

21. W – power The rate at which work is done. 1 Watt = 1 joule/sec. This unit links mechanical work with electrical work as well as providing a connection to pressure.

22. Pa - pressure one newton per square meter or one "kilogram per meter per second per second." A pascal is actually quite small (only 0.000 145 pound per square inch) and requires a prefix the majority of the time it is used.

23. Most common metric prefixes. kilo 103 hecto 102 deka 10 -base 1 deci 10-1 centi 10-2 milli- 10-3

26. The Big Yotta- 1024 Zetta- 1021 Exa- 1018 Peta- 1015 Tera- 1012 Giga- 109 Mega- 106

27. Commodore 64 TRS - 80 64 kilobytes RAM 4 kilobytes RAM Macintosh 486 PC 64 Megabytes RAM(max) 128 kilobytes RAM

28. This top of the line gaming pc has 32 Gigabytes of RAM Here are the others expressed in Gigabytes TRS-80 - .000004 Gbytes C64 - .000064 Gbytes First Mac - .000128 Gbytes 486PC - .064 Gbytes An average digital picture takes around 500 kilobytes An average music file takes ~3-5 Megabytes

29. Flash/thumbdrives up to 32 Gigabytes Ipods (4-160 Gigabytes) External hard drives up to ~3 Terabytes Desktop hard drive up to 8 Terabytes

30. 20,000 Tb processed daily (20Pb) ~100 Tb 1 Eb = 50 000 years of DVD 1.2 Eb = sum of Big Four (2014)

31. The little… micro- 10-6 nano- 10-9 pico- 10-12 femto- 10-15 atto- 10-18 zepto- 10-21 yocto- 10-24

32. There are 1,000 µm in 1 mm. µ = micro 1mm That means there are 1,000,000 nm in 1 mm

33. Many cocci bacteria measure around 1 µm (1000X) 1,000 of them could line up across the dime’s edge One bacterium is 1,000 nm across. How many microns? How many nanometers?

34. The wavelengths of the visible light spectrum Range from 400(violet) to 750(red) nm.

35. X-ray wavelengths measure < 10 nm 1 nm = 1,000 pm p=pico

36. The radius of a helium atom is estimated to be around 30 pm. radius

37. 1.6 x 107 helium atoms line up end to end on the edge of a finger nail. That’s ~16,000,000 atoms across. This is just the beginning of measurement…