How many ducks in a row?
NEW technology may require, or at least inspire, new units. Thus Samuel Merchant proposes that 鈥渢he 鈥榙uck鈥� now seems to be the unit of choice for 3D printing costs鈥�. He sends a selfie taken at last year鈥檚 exhibition 鈥溾�� at London鈥檚 Design Museum, next to a graph showing that 3D printing of plastic bath ducks was cheaper than injection-moulding for runs of 400 ducks or fewer. By coincidence, Samuel was wearing a duck T-shirt.
Feedback looks forward to seeing a 3D printer large enough to churn out blue whales 鈥� and baths big enough to float them.
On a recent trip to Malawi, Malcolm White was startled to find a stiff paper bag in a hotel bathroom labelled with the request to insert one鈥檚 鈥淪anity Towel鈥� for disposal
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Elephants branch out
TALKING of units, a steady stream of readers have developed the concept of the elephant as unit. Bearing in mind NASA鈥檚 problems with unit mix ups, Ian Bradley asks whether the unit is based on African or Asian elephants.
Pachyderms can measure more than just mass and force. Nick Lake quotes 7 Days, a free newspaper in the United Arab Emirates, describing the Bloodhound SSC, which is being built to attempt a land speed record. Its air brakes are, apparently, 鈥渆quivalent in drag to a large elephant鈥�. So, Nick says, 鈥渨e can add coefficient of drag to mass and force. As for elephants in drag鈥︹��
Pachyderm pressure at heel
FURTHER, Feedback鈥檚 piling system has thrown up John Gava鈥檚 mention of a Sydney Morning Herald on life in the Mariana Trench, at a pressure of 1125 kilograms per square centimetre, 鈥渁bout the same as being stepped on by an elephant wearing high-heeled shoes鈥�. By our calculations, taking a male African elephant to be standard, at 5000 kg, and ignoring buoyancy, he would have to be balancing on four moderate heels of just over 1 cm2 each.
Less elephantine
SOMEHOW the above discussion feels related to Martin Savage鈥檚 suggestion that we need a subdivision of the unit: the milliphant.
Kettle comparisons
FEEDBACK does understand that people are more able to grasp the significance of numbers that are related to their experience. So when Bob Dowdeswell alerted us to astrophysicist Carol Mundell telling BBC TV that the amount of radiation from the sun at the surface of comet ISON was 鈥渆quivalent to about 3000 fast-boiling kettles per square metre鈥� we rather approved.
Her comparison was certainly more sensible than Feedback鈥檚 tongue-in-cheek use of the kettle unit, with a supercomputer equivalent to 6 million kettles (6 July 2013). We still have to solve the problem of the difference between European and US kettles.
Below-average numeracy
THE BBC, Mike Moore observes, isn鈥檛 universally blessed with the ability to detect numbers that smell wrong, or olfactorithmetic (21 December 2013). On 9 December, referring to a study on gender bias in science subjects, it the Institute of Physics finding 鈥渢hat nearly half of the co-educational state-funded schools we looked at are actually doing worse than average鈥�, quoting curriculum and diversity manager Clare Thomson. Feedback refers the honourable gentlepeople to the definitions of 鈥渕ean鈥� and 鈥渕edian鈥� averages. Peter Main, IoP director of education and science, tells us this was 鈥渢aken out of context, rather unfortunately, by the BBC鈥�.
Tea trees not that tree
BEWARE the web. Feedback searched for 鈥渢ea tree鈥�, came up with the Australian Melaleuca alternifolia and assumed it was introduced to New Zealand (16 November 2013). Jonathan Wood implores: 鈥淧lease never mistake an Australian member of the Myrtle family with New Zealand鈥檚.鈥� Those are the Manuka or red tea tree (Leptospermum scoparium) and the K膩nuka or white tea tree (Kunzea ericoides) 鈥� although Jonathan laments that 鈥淜iwis can almost never tell these apart鈥� and love to fell them.
Magical manuka mantra
WHEREAS the Australian tea tree is favoured by 鈥渘atural remedy鈥� fans as a fierce antiseptic, honey from Manuka flowers is tasty and credited with many things. We find asking 鈥�?鈥� and we respond: 鈥渁ny headline expressed as a question begs the answer 鈥楴O鈥�.鈥�
The right tea tree
AND how should we feel about Ann Parkinson鈥檚 evidence that our tea-tree confusion is shared? She was invited to an 鈥淎ustralian version of a Maori 丑腻苍驳颈鈥�, a feast cooked on hot stones in a pit. 鈥淭he keen cook, an Australian, was busily layering lots of branches of the Australian tea tree around the food to be cooked鈥� My protests were brushed aside.鈥�
Ann invites us to imagine the flavours. We are trying to forget.
Your parcel of light
FINALLY, a UK delivery company informed Edward Parker it had 鈥�1 item: Total weight 0.000kg鈥�. 鈥淭hat,鈥� he says, 鈥渨ill be the anti-gravity machine I ordered last week.鈥�