Guests: Ross Noble, Brian Cox, Sue Perkins
Aired: 21st October 2011, BBC Two
Helium is the second most abundant element in the observable universe but we're running out of it on Earth. Helium prices have doubled in the past five years. The high demand comes from the need to cool the superconducting coils of magnetic resonance imaging (MRI) devices. Sales of MRI scanners have driven the demand for helium up by 25% since 2003.
In 2006 the USA supplied 71% of the world's helium needs, much of it from the federal helium reserve. The reserve was started in 1961, when helium was considered a crucial military resource, but it's now being run down. As a result, according to a 2000 National Academy of Sciences report, the total US helium resources will disappear by 2035 – probably sooner, because of rising demand.
The Noble Gases (helium, neon, argon, krypton, xenon, and radon) are so named as a translation from the German word Edelgas. The word edel has a connotation of aloofness – because they don't associate with other gases. A more colloquial
translation would be ‘Stuck-up gases’.
In 2001, Ian Ashpole from Hertfordshire broke the world record for the highest flight powered by party balloons (the earlier world record which he broke was already one of his). He flew up to 11,000 feet, lifted by 600 balloons. At that altitude he cut himself free and parachuted back to earth.
Spiders aren't insects - they are members of the class Arachnida, not Insecta. The main difference is that arachnids have eight legs while insects have six.
However, there are true insects that spin webs: web-spinners, or Embioptera. They look a little like termites, with small eyes, thread-like antennae and long bodies, although the male have rather delicate, fluttery wings (their name means ‘lively-winged’ in Greek). They make silk-lined tunnels and webs under stones, in the soil or in dead wood. The tunnels protect them against predators such as centipedes. The tunnels also help to maintain the right temperatures and humidity for them to live. They spin their silk from glands in a swollen joint of their front legs. No other insects are known to have silk glands in this position. Unlike silk worms, which only have one pair of silk glands per individual, some embiid species are estimated to have up to 300 silk glands.
Other insects which spin webs include psocopterans (booklice), some symphyta
(sawflies), yponomeutidae (moths) and psychidae (bagworms).
You can now make goat silk as well as silkworm silk. Canadian scientists have implanted the silk-producing gene from spiders into goats. Mammals produce milk proteins in very much the same way that spiders make silk proteins. As a result, when the specially treated goats lactate, their milk contains 'recombinant' silk, which can be harvested, dried and spun into fibres.
A child of five would understand this. Send somebody to fetch a child of five.
In mathematics you don't understand things. You just get used to them.