• https://nrich.maths.org/9088
• https://www.youtube.com/watch?v=eeqrN3Bfro8&feature=youtu.be
• 2014/08/07 : Quickly now - which is heavier: A pint of milk, of a pint of cream?
• 2015/03/25 : The fraction 16/64 can be simplified by cancelling the 6's, and 19/95 can be simplified by cancelling the 9's.
• 2015/06/01 : [ sqrt(2)-1 ]^n is always the difference of the sqrts of consecutive integers
  • For example, (sqrt(2)-1)^3 = sqrt(50)-sqrt(49)
    • TomButton says:
      • The 2 numbers are 1 apart and are always a square and twice a square.
      • Multiply and divide by 2 - result is triangular and square.
      • Hence there are infinitely many triangular squares!
• 2015/06/05 : If clouds are made up of water, they must be heavy. How do they float?
• 2015/07/28 : What do you get when you photocopy a mirror?
• 2016/05/14 : An ounce of gold weighs more than an ounce of feathers.
• 2016/05/19 : There are pi seconds in a nano-century (to within 0.45% or so)
• 2016/12/03 : The digit sum of the product of twin primes is always 8.
• 2016/12/22 : In 1s a ball falls ~5m, and from 5m up the distance to the horizon is ~8km. Hence orbital velocity at grazing altitude is about 8 km/s.
• 2017/04/11 : 10! seconds is exactly 6 weeks
• 2017/04/19 : Take a positive integer, reverse the digits and concatenate. The result is divisible by 11. Why?
• 2017/04/22 : The speed of light is faster than the speed of sound. That's why some people appear to be smart until they start to talk.
• 2017/04/25 : Drink Coffee!! Do stupid things FASTER, and with MORE ENERGY !
• 2017/05/09 : On a body, the line separating light from dark is the terminator.
  • From Earth, is the Moon's terminator ever a vertical straight line?
• 2017/05/17 : The speed of sound (in air at sea level) is almost exactly a million times slower than the speed of light.
  • Roughly 1ft/ms vs 1ft/ns. Coincidence, or conspiracy ...
• 2017/05/22 : The Opaque Forest problem - as yet unsolved, even for the square and triangle.
  • https://en.wikipedia.org/wiki/Opaque_forest_problem
• 2017/05/23 : Q: what's the 99th digit to the right of the decimal point in the decimal expansion of (1+sqrt(2))^500 ??
• 2017/06/02 : Park when the ground is wet, leave when it's dry.
  • The area of the wet patches times the tire pressure gives the weight of the car.
• 2017/06/28 : "One can measure the importance of a scientific work
  • by the number of earlier publications rendered superfluous by it."
    • - David Hilbert
• 2017/07/09 : "Never try to teach a pig to sing. It wastes your time and it annoys the pig" -- Robert Heinlein
• 2017/07/23 : Why is sqrt(2)+sqrt(3) close to pi?
• 2017/07/25 : Find 5 common English words in differing by only one vowel.
  • How long can the words be? Can you find an interesting quintuple?
• 2017/07/27 : The def'n of the metre was going to be
  • the pendulum length with a 1 sec half-tick,
    • hence g ~ pi^2. For some def'n of 'hence'.
• 2017/08/24 : Your laptop processor clock probably runs faster than 2GHz.
  • At that speed, in the time of one clock tick, light travels about 6 inches.
• 2018/03/18 : What do you give the person who's got everything? Antibiotics.
• 2018/04/01 : A new (to me) definition of the irrationals:
  • The set of all real numbers having different distances from all rational numbers.

Quotation from Tim Berners-Lee