UV 2 is benign, UV 4 begs sun cream, UV 6 requires respect, but is the scale linear (like Volts), logarithmic (like dB or Richter), linear with an offset base (like Celsius or British dress sizes);...
At 10 000 m altitude a balloon is cold, but a meteor is hot. What would be the temperature of the nose of an aircraft flying at (say) 600 km/h? Ignore conduction and radiation, or masochists can...
When someone plays a stringed instrument - not a piano - left-handed, do they reverse the order of the strings? i.e. does a left-handed guitarist or violinist still have the higher-pitched strings...
How could we detect a magnetic monopole, and why is it said that if a single magnetic monopole exists then all the electrons in the Universe must have the same rest mass?
Wouldn't it be a good idea if every smartphone contained detectors for smoke and carbon-dioxide? They would always be charged and working. Does anyone know if any smartphones already have them?
I've bought a second-hand automatic car for the first time and I'm confused by the gear lever. I've driven it for a fortnight using just forward and reverse, and keeping my foot on the brake at...
This is my last unsolved clue of the Great Wall Crossword No. 1 CLUE: Course of action. LIGHT: ?R?D?S? ANSWER: I can think of only CRUDEST or PRUDISH. I'm tempted to enter CRUDISH just to finish the...
149 down in the Great Wall Crossword no. 1
Clue: Jacket with cotton centre?
Light: ?O?B?E?
The answer looks like DOUBLET, but what is the cotton centre?...
If the Universe ends with a Big Crunch is "empty" space left behind or does it disappear. In fact, does space every disappear e.g. near a black hole?...
If you hold the ends of an axle with each hand then turn the axle through 180 degrees so that your left hand holds the end that the right hand held, how will a bicycle wheel previously free-wheeling...
A mirror has 60 LEDs, each lasts 5000 hours on average. When, on average, will the first LED fail. Obviously it depends on the spread of failure rates. 60 candles would all fail at similar times. So...
Is it possible to read books on a Hudl? I've downloaded a Kobo book and a Kobo app, thinking that was the way to go, but the app doesn't seem to see the book. Also, if anyone knows how to remove a...
What's wrong with this argument? Twelve billion years ago the Universe was less dense than it had been thirteen billion years ago, but more dense than it would be eleven billion years ago. So...