The Instant Physicist

An Illustrated Guide

Richard A. Muller, Joey Manfre artist

Mult.Co. Gregory Heights: 530 M958i 2001

Quick and amusing, mostly familiar, but facts new to me, and a few blunders. This isn't a good physics text, but it might motivate a smart 12 year old to buy a real physics text, and it might amuse a non-scientist.

• p10 C14 half life 5700y

• p12 Muller worked on accelerator mass spectrometry
• drinking alcohol required to have 400 radioactive decays per minute per 750 milliliters to rule out petroleum source
  • check this: ... 1e-12 C14 in atmosphere, 5700 year half life is 5700*365.24/ln2 = 3e6 days = 4.325e9 minutes
  • 400 decays per minute is 400*4.325e9*1e12 = 1.73e24 carbon atoms = 2.874 moles = 34.5 grams / 750 ml
  • 12% alcohol by volume is 90 ml / 750 ml, ethanol density 0.7893 * 24/46 = 37 grams / 90 ml ethanol ... plausible

• p16 Tesla Car: $30,000 / 3y to replace batteries, $10K/y . Prius makes more sense
• p18 Tsunami: 30 foot rise in 2 minutes, one foot / 4 seconds tsunami = harbor wave, behaves like fast tide
• p20 ERASER: electromagnetic radiation amplification by stimulated emission of radiation
• p30 300 rem sick, 1000 rem kill, 2500 rem / lots of people = 1 cancer ... maybe?

• p34 BULL ... 3 square miles per gigawatt? no ... multiply 1000W/m² by (1-cloudiness)*cos(latitude)/π .

  • Nevada averages 5 kWh/day or 208 W/m² average

  • assuming 0.9*35% efficiency averaged over 25 years, that is 66 W/m²

  • 66 * 1609 * 1609 = 171 MW average per square mile, about 5.9 square miles at perfect efficiency
  • GREATLY reduced by power conversion, energy storage, and transmission costs; customers tend to use more power when it is cloudy or dark, and some of that power comes from sunny places far away. Call it 10 square miles, or 6400 acres of manufactured electrical systems. More expensive than a parking lot, less expensive than a warehouse.
  • Solar makes sense for many things (like fiber repeaters and signal lights far from the grid), but for bulk grid power, not so much.

• p30 BULL HAL the intelligent computer "too big"? Neural signalling is 100 m/s. Electrical signalling on a circuit board is 140e6 m/s, more than a million times faster. Uniprocessors are made small because signalling uses power, smaller processors use less power, and power cost is more important than chip cost (for both computers and brains). What Kubrick and Clarke got really right was that future computers will be modular, perhaps optical, and that abstract glowing light bricks are "less wrong" as future technology than a 1960s circuit board.

• p44 "Some people are reputed to have four color sensors, not three" tetrachromacy from X chromosome differences in 2-3% of women

• p46 BULL P (pressure) waves are √3 faster than S (shear) waves, not 17/16 faster (the root-3 relationship was postulated by ??? from basic principles of elasticity) . P-wave speeds are 5000 m/s in granite - 11,000 miles per hour, not 1,000 miles per hour.

• p66 In 1979, the Three Mile Island accident exposed the public (millions of people) to 2000 person-rem, and nobody got more than 0.07 rem.

• p92 BULL clouds rise until they reach warm air? No ... water vapor rises and cools (loses gravitational energy) until it condenses (wet adiabatic lapse rate). Denser dry air cools faster (dry adiabatic lapse rate). The stratosphere is very cold and bone dry. It is true that the ozone layer is above that, but quite a ways in most places.

• p94 Enercon wind turbine in Germany is 600 (now 650) feet high at blade-top.

• p96 Electrocution of Topsy the Elephant by Edison to "demonstrate" the dangers of high voltage AC, January 4, 1903 .

• p106 "More hurricanes" because we track them over oceans with satellites, not just the ones that make landfall. Katrina was category 3 when it hit New Orleans, the first since the levees were built.
• p110 Natural pesticides typically 1000x more carcinogenic than the artificial ones. Muller eats organic because it tastes better (not so, according to Penn and Teller). I eat organic because it is a mediocre approximation of good long-term land management for some crops, but I worry that it takes more land away from nature.

• p114 BULL highest energy chemical fuel shoots backwards at less than 1 mile per second. Actually, the "specific impulse" of liquid hydrogen/oxygen is 450 seconds - multiply that by "gee" and your get 4400 m/s, or 2.7 miles per second. A "mile long railgun" - an electromagnetic accelerator for human/machine cargo would be MUCH longer, though the exit must be well above the dense atmosphere (mountaintops are too low). A 3 gee launch loop is 1000 km to orbital velocity, 2000 km to escape.

  • note: John Hunter built a hypervelocity gas gun for the Air Force; breech velocity above 4000 m/s! When I complained that you can't send complicated objects like electronics through such wrenching accelerations, he pulled out his cell phone and said "make a call". He explained that the phone had extra potting compound added around high mass components inside, that it was very well cushioned, and that the batteries were removed; but still, way cool.

• p116 Math Error 100 kilotons or 100,000 tons of TNT.

• p138 Portugal's Agucadoura Wave Park had three 750 kW, 140 meter long generators. Corrosion and bother, and ecological damage.