Lv 624,133 points


Favourite answers25%

Born 1948 male live in far south of NZ.

  • Why can't a radio aerial emit optical frequencies?

    Why can.t you make a conductor glow by feeding in alternating current at a frequency in the range 10^14 Hz?

    1 AnswerPhysics7 years ago
  • Why do we never hear about teraherz lasers?

    Masers (microwave lasers) have been around since the early 1950s. Lasers were invented in 1958. So we've had the technology to make teraherz lasers for more than 50 years. We're only now starting to develop other aspects of teraherz technology, like cameras that can view your internal organs without zapping you with Xrays. Why aren't there any lasers in the 10^-5 metre wavelength range? They'd be bloody useful.

    1 AnswerPhysics8 years ago
  • Why are people reluctant to divulge their bank account details?

    I often ask somebody for the name and number of their bank account so I can pay them by Internet, and they refuse. How could this information be abused? And what's the difference from paying by cheque, since the cheque carries the same information?

    2 AnswersPersonal Finance8 years ago
  • Can you derive the speed of light from non-electromagnetic constants?

    In the nineteenth century, James Clerk Maxwell discovered that the electrical permittivity times the magnetic permeability of space = 1/speed of light^2, which makes sense because light consists of electric and magnetic field disturbances. But some non-electromagnetic entities travel at the speed of light too. Like neutrinos, which are a weak force phenomenon, and gravity waves which of course are a gravitational field disturbance. Can you derive c from weak force or gravitational constants?

    2 AnswersPhysics8 years ago
  • Why aren't refracting telescopes built using Fresnel lenses?

    The world's largest refracting telescopes are pathetically small compared with the largest reflectors, for obvious reasons. I mean, imagine driving the truck carrying the lenses up that mountain in Hawaii. I'm reading an Arthur C. Clarke book about saving the world using a huge Fresnel lens in space. Fresnel lenses can be as thin as you like. Why don't we use existing technology to build both Earth- and space based Large Fresnel lens refracting telescopes?

    4 AnswersAstronomy & Space8 years ago
  • How do you get decent low-energy illumination?

    Here in New Zealand, low-energy compact fluorescent light bulbs are bloody pathetic. The brightest one on the market consumes 20 watts and gives the equivalent brightness of a 100 watt incandescent bulb. The only room in our house where you can read in comfort has a chandelier with five of them. What can be done about this problem at a reasonable cost? Why can't you buy compact fluorescent lights with a reasonable light output? In this country power supply is 230 volts, and light bulbs have a bayonet fitting. Are usable low power bulbs available anywhere in the world? Even our local electrician can't give me an answer.

    4 AnswersGreen Living9 years ago
  • Why can't you make a regular solid with an arbitrary number of faces?

    In scool we were taught that there are only a few regular solids, and they've all been known since Classical Greek times. Imagine this experiment. You've got a transparent, insulating hollow sphere, made out of, say, polycarbonate. It's in two hemispheres, which you can separate, so you can open it. You've got a whole lot of light pith balls, coated with metal foil, all with the same mass. You give all of them the same electrical charge, place them inside your sphere and close it. You do this in microgravity, say, in the ISS. They all repel each other, so they're all the same distance apart, so they're the vertices of a regular solid. You could do this with any number of balls. So why couldn't you join them up with straight lines and make a line drawing of a regular solid with any number of faces ?

    2 AnswersMathematics9 years ago
  • What's radical about the Slingshot water Purifier?

    I'm reading a brilliant book by Peter Diamandis and Steven Kotler, titled Abundance. They describe a device called the Slingshot which can turn seawater or sewage into clean water, pure enough to be usable in a dialysis machine, for a very low cost. It sounds like an ordinary flash distiller, like they use at sea. What am I missing?

    3 AnswersOther - Health9 years ago
  • How far underground does a country's territory extend?

    Gambia is a long thin country along the banks of the Gambia River, which almost bisects Senegal. Driving across Gambia from one side of Senegal to the other is such a hassle that the Senegalese are seriously considering building a tunnel, about 40 km. long, under Gambia and the Gambia River, so you can drive from one side to the other without making a long detour around Gambia, and without going through customs and immigration. According to international law, would the tunnel be inside Gambian territory? In other words, a country's territory extends 12 nautical miles beyond its coastline and 100 km. above its surface. How far below its surface does it extend?

    2 AnswersOther - Politics & Government9 years ago
  • why doesn't our insect zapper work?

    We bought an insect snuffer like those you see in butchers' shops. It consists of a UV lamp surrounded by high voltage wire. The UV light is supposed to attract insects and the high voltage is supposed to electrocute them. Only trouble is, it hasn't killed any insects. What's wrong with it? What's the most effective way of snuffing insects in your opinion? You used to see fly papers and Shell pest strips in the shops and they seemed quite effective. Now you don't see them. Why not?

    2 AnswersOther - Home & Garden9 years ago
  • Did Kim Jong Il do poopy-plops?

    Many North Koreans believe that their late leader didn't defecate. Everybody I know does (poo, that is), but I've never been to the DPRK. What do you believe?

    4 AnswersPolitics9 years ago
  • Why does Eritrea score lower than North Korea for press freedom?

    North Korea has no independent news media. How can any country score lower than that? In what way(s) does a journalist in Eritrea have less freedom than in the land of the Dear Leader?

    2 AnswersPolitics9 years ago
  • Why is coal ash bad for the garden?

    Coal and lignite are just plant material, so how come rotted compost is good for plants but coal and lignite ash are full of heavy metals etc.? And is peat ash good or bad on the garden?

    4 AnswersGarden & Landscape9 years ago
  • What's the tensile strength of a buckytube in Pa?

    And is a buckytube the ultimate limit in strong materials? The reason I'm interested is to work out if a space elevator can ever be made.

    1 AnswerEngineering9 years ago
  • Questions about Happy Feet.?

    Recently an emperor penguin who we named Happy Feet arrived in NZ. He must have swum 3 000 km from the Antarctic to the North Island. Penguins, like us, need fresh water, and they normally get it by eating snow. How would he have got it on his long sea trip? Did he eat by just sticking his head underwater and grabbing fish? He had to be operated on to remove sand and twigs which he'd ingested instead of snow, so the only place where he'll be safe is back on the Ice. He's going to be released in the sub-Antarctic. How do they know he won't just head north again? And why would he make a trip like that anyway?

    2 AnswersZoology9 years ago
  • Can you drive from Moscow to Vladivostok?

    If a road exists, what is it like?

    8 AnswersRussia10 years ago
  • cold Beef Wellington?

    At a going-away party in the Seychelles we were served a hot-weather version of Beef Wellington. It was served chilled, accompanied by salad veges and iced soup. Between the puff pastry shell and the beef fillet was a layer of something that resembled pate and savoury jelly. Does anybody know the recipe please?

    1 AnswerCooking & Recipes10 years ago
  • Why should you let Yorkshire pudding mix stand?

    All the cookbooks say you should let Yorkshire pudding batter stand for at least an hour after mixing. We all agree that a good Yorkshire pud should be light. I'd have thought that putting it in a hot oven immediately after mixing would trap more air in it. What am I overlooking?

    2 AnswersCooking & Recipes10 years ago
  • Why can'y you buy bacon that's crisp when it's fried?

    When I was a kid in Britain in the 1950s,the bacon my muvver served for breakfast was crispy and delicious. I haven't tasted it for decades. A butcher told me the reason it's unobtainable is because it was carcenogenic. Is this true? If so, what was the reason, and how serious was the risk? Is there an alternative safe way of making crisp bacon?

    5 AnswersOther - Food & Drink10 years ago