Handy way to test lava
QUESTION How are the excessively high temperatures in volcanoes measured?
A THERMOCOUPLE probe can be inserted into a lava flow and the temperature can be read off a hand-held device.
A thermocouple takes advantage of the thermoelectric effect, also known as the Seebeck effect. In 1821-3, German physicist Thomas Seebeck found that a circuit made from two different metals, with junctions at various temperatures, would deflect a compass magnet.
This is because the temperature difference produces an electric potential (voltage), which can drive an electric current in a closed circuit.
A thermocouple can use the Seebeck principle to determine extreme temperatures using the fact that the size of that current is directly related to the difference in temperature between the two junctions.
Inserting a thermocouple probe into a lava flow for long enough to get a good reading is a perilous business.
Volcanologist George Walker said: ‘The temperature of a lava flow is inversely proportional to the comfort of the volcanologist making the measurement.’
Where temperatures are too extreme for the volcanologist to get near, a thermal IR imaging camera can be used.
This offers a non-contact way to quickly measure temperatures. However, these will accurately measure only the surface temperature of the lava. Scientists must then use mathematical modelling to calculate temperatures deeper into the flow.
QUESTION Is it true that V1 and V2 flying bombs were not launched against Russian targets in the East during World War II?
V-WEAPONS, or Verge ltungswaf fen
(‘ retaliatory weapons ’), comprised the V1 (a pulse jetpowered cruise missile) and the V2 (a liquid-fuelled ballistic missile). While designed for strategic bombing during World War II, their poor range and accuracy meant they were only deployed in the West as an indiscriminate terror weapon.
The V1 and V2 had deficiencies that made them unsuitable for firing into the vast wastelands of Russia. Neither weapon was particularly accurate. They had a circular error probable (CEP) of several miles. They were useless against tactical targets, troop concentrations, railways, roads or other systems supporting the fronts. They could barely target a town, let alone a bridge, dam or power station.
V1 and V2 attacks on British cities were terror attacks: an attempt to destroy morale and put an end to the war in the West. To the East, despite there being a couple of V1 test sites in Poland, it was quickly realised there weren’t enough population centres in range for terror attacks. V1s had a range of 240km and V2s around 320km.
V1s were launched from aircraft or, in the case of the British front, from sites in France and Holland.
It would have been impossible to deploy the V2 to the East given the substantial support required to mount operations.
QUESTION Diplomats at the US embassy in Havana, Cuba, claimed they were under sonic attack from microwave weapons. Was this the case?
IN LATE 2016, US diplomats in Havana began to report ear pain, headaches and nausea and other symptoms from a high-frequency noise. The effects, which doctors said were similar to a concussion, were exhausting and lingered for weeks.
In early 2017, Washington withdrew half its embassy staff and expelled a number of Cuban diplomats in the belief they had been targeted by an acoustic weapon.
A sample of the noise, a persistent, high-pitched drone, was released to the press.
Analysis of the audio recording revealed that the noise is almost certainly the song of the Indies short-tailed cricket, Anurogryllus celerinictus. The call of this Caribbean species is delivered at an unusually high rate, which gives humans the sensation of a continuous sharp trill.
Kevin Abrahams, Cardiff.
QUESTION The film title Krakatoa, East Of Java is incorrect because the volcano is west of Java. Are there geographical blunders in other movie names?
FURTHER to the earlier answers, this reminded me of a discussion about Alfred Hitchcock’s film from 1959, North By Northwest, between old seafarers in my home village of Passage East – which is adjacent to Waterford Harbour – when I was a boy.
The consensus was: ‘There is no such point on the compass as north by northwest. It should properly be known as “northwest by north”.’ However, when I later went to see the film, I realised that the title actually referred to the name of the airline in the story (Northwest Airlines) and not the point on a 32-point compass rose.
QUESTION What is the strangest Death Row meal request? FURTHER to the previous answer, the full details of the last meal
requests made by nearly 400 men and women executed by the state of Texas between 1982 and 2007 are listed in Texas Death Row (Last Words. Last Meals. Last Rites), edited by Bill Crawford.
On average, an inmate on Texas Death Row has 10.43 years to ponder over what their last meal will be.
A number of inmates forgo a last meal, but most order food that reminds them of home and better times. There are few requests for fine dining – it is the sheer volume of food requested by many that appears to be strange.
In 2005, Douglas Roberts ordered three Southern fried chicken breasts, tomato, lettuce, cheese, picante sauce, jalapeno peppers, two BLTs on wheat lightly grilled with garlic butter, three beef and cheese enchiladas, 12 green olives, Italian ketchup, butter beans and cabbage seasoned with ham bone, seasoned ground beef, six corn tortillas, onions, fried onion rings, French fries, four devilled eggs, broccoli with cheese sauce and two grilled barbecue pork chops.
No record is kept as to whether or not inmates finish their meals. Requests for alcohol and cigarettes are refused.
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