assembly line astrology and astronomy mechanical clocks sextant huntsman steel precision in...
TRANSCRIPT
Assembly Line
• Astrology and Astronomy• Mechanical clocks• Sextant• Huntsman steel• Precision in manufacturing• The lathe• Standard interchangeable parts
600-539 B.C.
• Astronomers divided the sky into twelve constellations (clusters of stars), 30 degrees apart in 360 degrees.
• This marked the beginning of the pseudo-science astrology.
760AD- Caliph, Al Mansur became ill
• Seemingly cured through assessment of star positions and Gundeshapur medicine.
• Lead to increased study of star positions and improvement of the Astrolabe.
Translated Arab into Latin
• The Almagest (Arab translation of Ptolemy’s star table) and many other texts were translated into Latin during the 12th century.
1276 – Alfonsine Table Is Standard Star Reference
• By 1276 the king of Castile ordered a compilation of star tables called the Alfonsine Tables. Later these star positions were worked out for Paris and other places.
When Is It Time to Pray
• St. Benedict specified certain activities at certain times of day and night which led to the water alarm clock.
• 11th Century – Water alarm clock (Clepsydra) developed.
A Modified Clepsydra
First All Mechanical Clock
Verge and foliot escapement
1290AD -Verge and Foliot Escapement
• This all mechanical clock was widely used by priests.
• By 1400 AD clocks were telling people when to work. It increased productivity.
• Accurate to within 15 minutes per day.
Verge and Foliot clock in action
A Venetian 24hr Clock
AM and PM
• AM comes from Latin for “ante meridian”,which means before noon.
• PM comes from Latin for “post meridian,” which mean after noon.
• The 12 clock chimes are easier to understand.
1450 AD portable clocks
• Driven by a carbon steel spring and controlled by the Fusee
• Carbon steel was made by heating carbon and iron together, then hammering off the hard carbonized steel.
FuseeSpring driven barrel
Blister Steel
1608- Lippershey’s“Looker”
• A telescope intended for military purposes but led to Galileo to confirm Copernicus that the Earth is not the center of the universe.
John Dollond’s Achromatic Lens 1758
• Early telescope lenses bent different colors differently resulting in a blurry image.
• Dollond’s lense was made of Flint and Crown glass both canceling each others color aberrations. Result was a sharp image.
The Pendulum Clock
• Galileo’s experimentation of pendulums led to Huygen’s, pendulum clock.
• First ones only accurate to 10min/day.• By 1725 engineered escapements
allowed accuracy within 1 second per day. Nevertheless, this clock was useless at sea.
Modern Escapements
• A British clockmaker George Daniels invented the co-axial escapement first used by Omega SA in 1999.
• The design uses radial friction instead of sliding friction. Resulting in longer life and improved accuracy.
• See the Daniels co-axial escapement in action
Verge and Pendulum Escapement
How it works
1731 – John Hadley’s sextant
• A precise astrolab, capable of measuring angle between two objects such as the sun and horizon.
• The first measuring arcs were etched by hand so they had limited precision.
1740 – Huntsman Steel
• Benjamin Huntsman was a clock maker dissatisfied with current steel quality. He developed ”crucible steel.”
• Extremely hard uniform steel perfect for clocks.
• Helped to trigger the industrial revolution.
See how steel is made today
1774 – Jesse Ramsden’s Dividing Engine
• Triggered by Hadley’s sextant, which demanded more precise arc divisions.
• Jesse Ramsden’s Dividing Engine used a steel tangent screw made using a Huntsman steel cutting tool.
The Dividing Engine
Interchangeable Parts
• Honore Le Blanc in France gave the idea of interchangeable parts for making guns to Thomas Jefferson.
• USA in 1798 became first to make guns with interchangeable parts.
1808 – Maudslay’s Lathe
• Used in England to make ships blocks in the worlds first modern assembly line. His lathes were extremely precise
First Standardized Assembly Line
• Terracotta Army
• Assembled 2200 years ago.
• >1800 life size soldiers, weapons, horses, chariots.
Ship Blocks• These are simple
pulley systems.
• Force is reduced by 1/n where n is number of lines or pulleys supporting the load.
• Four pulleys make 100 Lbs feel like 25 Lbs.
Work = force x distance
Automation not a threat here
• Much cheap unskilled labor in USA.
• Interchangeable parts and the assembly line led to great growth in jobs and exports.
• Later, time/motion studies by Taylor and Gilbreths perfected the assembly line.– Ford’s B-24 Bomber
Accuracy
• Closeness to true value
• The accuracy of an analytical measurement is how close a result comes to the true value. Determining the accuracy of a measurement usually requires calibration of the analytical method with a known standard.
Precision
• Reproducibility of results
• Precision is the reproducibility of multiple measurements and is usually described by the standard deviation, standard error, or confidence interval.
Accuracy and Precision
Taking the long way home
• John Harrison’s highly precise clock designed for ships.
• Solved the longitude problem.
• 15 degree longitude (approx. 1000 mi) per hour.
Harrison’s H4
• Completed in 1759• 13 cm (5.1 in) in
diameter and weighs 1.45 Kg (3.2 Lbs).
• Off by only 39.2 s/47 days or 0.83 s per day
• Better than twice the required precision.
Harrison’s H5
• Tested by King George III in 1772
• It was off only 0.3 second/day
• Harrison did not received the £20,000 “prize” from the Board of Longitude in his lifetime.
Time & Longitude
• 15o/hr or approx. 1000 mi/hr
• Check “home” chronometer from ship at “high noon”
Home time
Δ time
Home is
You are
1PM 1hr 15o E 15o W
2PM 2hr 30o E 30o W
10AM -2hr 30o W 30o E
Longitude
• An international conference in 1884 set the Royal Observatory in Greenwich England as zero longitude.
• A laser beam shoots North along the prime meridian.
Readings: “Taking the Long Way Home”
• Longitude lines are the vertical meridian lines. Zero longitude is Greenwich England.
• Latitude lines are the horizontal lines. Zero latitude is the equator.
• The longitude of South tip of Africa is approx. 20 E longitude & 35 S latitude.
• S. tip of S. America is approx. 75 W longitude & 55 S latitude
What you should know
• Differentiate between astronomy and astrology.
• Why 12 months in the year and 12 hours each day and night.
• Differentiate between accuracy and precision.
• Operation of water alarm clock, mechanical clock, portable clock and pendulum clock.
• Astronomy is a science
• From 12 moons/year
• Slides #27-29
• Slides #7-12 and #15-17
What you should know
• Why did astronomers prefer the pendulum clock.
• The Latin and English translation for AM and PM.
• The connection between the “looker,” the sextant, and the need for more precision fabrication.
• Why was le Blanc unsuccessful installing his standardized gun parts in France? Pg. 150
• Increased precision
• Ante and post meridian
• Slides #18-21
• It threatened gunsmiths in Europe.
What you should know
• How a lathe works
• The connection between Huntsman steel (crucible steel), the lathe, tangent screw, dividing engine and the sextant.
• How ships blocks work (LN).
• Why the assembly line flourished in the U.S., not in Europe.
• Burke 144, video
• Slides #19
• Divides work by number of pulleys #25
• Cheap, abundant unskilled labor in the U.S. not in Europe.
What you should know
• How the American System of Manufacturing affected U.S. citizens and military
• Sailing from London at high noon your chronometer reads 2:00PM? What is your new longitude?
• Describe the construction of Dollond’s achromatic lens
• Corrective lenses 1300, the “Looker” 1608, why did it take 300 years for this?
• Burke 149-151.
• London is ahead (East) so you are West 2hr x 15o/hr =
30o longitude. #33-35
• Burke 141 & slide 14
• Burke 134-5