ol the small howel. ending with an ileostomy twhy bother to stop at the appendis'.’i.

All the external and internal gettitalia ean he remoy ed. as ean the spleen. the panereas. most ol the liyer arid gall hladder. at least oite lttitg and possibly a lohe trom the other. tlte laryny witlt a lt'aeheostonty. one eye. hull] e\ternal and one interttal ear. teetlt and hair. \Ve eould niggle ahottt how many fingers a person rttigltt need. httt to lose a thttnth is \ery disahling.

Why does human excrement smell so badly?

VL a" ‘f

'l'he smelly suhstanee itt eserement is skatole t3- methylindole). and it is the suhstanee to wltielt the human nose is most sensiliy'e on a per moleettle hasis. No dottht it is present in liteees heeause it is a hreakdown prodttet l'rom haetnoglohitt tltat enters tlte gut \‘ia hile. We haye ey'oly'ed to he repelled hy it heeattse eserement transmits disease attd we shottld steer elear.

llow'ey'er. skatole doesn‘t always trigger tlte disgust reaetion in humans. nor is tlte reaetion shared hy tlte whole animal kingdom. The suhstanee is used itt small amounts as llay'ouring itt t'ood. notably in y'anilla iee-eream. 'l‘he eiyet eat also has glattds that prodttee skatole. presttntahly to ntark territory attd repel others. This glattd is used in perl'ttmery.

I was recently in the Scottish Highlands taking refuge in my tent while squadrons of blood-hungry midges circled outside. The glen was devoid of humans and sheep, so I wondered how the midges survived.

Only the females ot‘ the biting speeies ol' tnidge

suek hlood. They need proteins attd tats for

making eggs. .‘ylales seek no stteh luxuries itt harren glens. nor do they risk their liy'es attaeking dangerous hosts: alter all. sperm is eheap.

Where eonditions t‘ay'our the growth ol' l'ly

laryae and myriad adults emerge ready for

mating. it does not follow that eaeh is guaranteed a meal. Only the lueky'. the aggressiy e and the hest hloodwinners sUI'ViVe to hreed. But then.

eyen a suryiyal rate ol one tit It)“ should more than maintain the population.

The lligltland ntidge is tiny. with just a 1.4mm wingspan. httt \ery dedteated seientists who hay e sat it ottt reeord that a swarm ot midges ean deliy er as tttatty as Flint) hites iii a single ltottr.

I recently flew back from holiday on a large airliner. During the flight we encountered severe turbulence. Even the cabin crew were alarmed, crawling along the aisle to take refuge. The plane seemed to fall vertically for about five seconds, and it felt as if it was going to fall out of the sky. Has that ever happened?

The elleets tlL‘sel‘il‘etl are Ul- ele‘ttl‘ Ltil‘ turhulenee. or (‘.-\'l'. l’ilots are ttnahle to see ('.-\'l‘. attd it eatt indeed eattse an attend! to et‘aslt. espeeially il etteountet'ed jltsl alter {disc-till. ttl‘ jllsl helittl‘e landing. Sinee Wh’l. there hay e heett more than 350 reports ol' aireral't rttttttittg into serious llll'litlleltce. 'l‘he eneouttter deserihed ltere seems to hay e heett eattsed hy jet stream turhttlenee. ()n long l'lights. aireralt try to lily along the jet stream it they ean. httt sinee this is usually lottnd at altitudes ahoye «llHlllll leet. planes olten l'ly

jttst helow it. wltere there ean he turhulent /ones.

It art aireralt at erttising altitude eneotmters a downdral't. the wings lose lil't attd the aireralt

drops suddenly. Anyone or anything rtot lastened down then hits the eeiling with y'ary'ing degrees or t‘oree. and it is ttsually the flight attendants wlto stiller injuries as a result. When the aireral't llies ottt ol' the downdral‘t. the wings regain hit with a lottd hatrg. .»\ireratt wings are designed to withstand 1.5g ol' negaliy'e lil't attd 2.5g positiy e

any more than this artd damage will oeettr.

()n 5 Mareh Who (‘.’\'l' eattsed a major disaster. ()n a elear day' the pilot of British ()yerseas Airways ('orporation llight 9| l deeided to make

a detour to give his passengers a sightseeing tour

ot- .\lount Fuji. The Boeing 707 hroke apart as a result of the sey‘ere turhulenee eneountered as the aireralt llew too elose to the mountain.

How fat would you have to be to be bulletproof, so that your fat layer would prevent a bullet fired from an ordinary handgun from reaching your vital organs? :\ human hody w ottld ney'er he entirely httlletprool when you take ittto eonsideration tissues and appendages sueh as the hands. feet. eyes. ears and male genitals. liy en it‘ the skin was sul'lieiently thiek to stop a httllet. the shoek w aye eottld seriously harm internal organs and the network ol' nery es helow the skin. art el‘l'eet whieh shot pellets esploit. l’ellets t'rom a shotgun ean kill a human without penetrating the skin.

A hullet's depth ot‘ penetration in a hody depends on a numher ot‘ taetors. sueh as the

hullet’s energy. diameter. mass. shape attd material. Bullets t'rom rttles attd handguns may range trom approsimately 5 to limm tn diameter attd tiom “’(l to TtNltl joules itt ettergy. .\ typieal poliee handgun hullet has a diameter ol' 0mm and art initial energy ol Sill) joules. l’enetration depth is measured tn a gelattne hloek. aitd the poliee ltattdgtttt httllet typieally penetrates ahottt ~illem ol' gelatine at a tlistanee ol. 5 metres hour the harrel.

’l‘he .\losteller tormttla giyes an indiyitlttal's hotly sttt'laee area itt stjttare metres as the square root ol' the prodttet ol' their height iii eenttmetres attd their weight itt kg. all diyided hy (rt). lot a tttatt l75em tall and weighing 75kg. this yields a hody sttrl‘aee area ol' IUImZ. So itt order to eoyer this area with a ,illem-thiek layer ol' lat with a density til I grattt per em3. we would tteed at least 573k; When you add this lo the weight ol‘ the hody. you lind that a typieal hulletprool person would weigh ahottt (rfitlkg.

How do you make candyfloss out of just sugar?

To make the sugar ‘eottony‘ you need tour things: heat. to melt the sugar and tttrtt it into a liquid: at set ol' \ery small holes through whieh the liquid sugar ean How to hunt threads; a spinning head that slings the liquid sugar outwards. loreing it through the holes: and a howl to eatelt the threads. The head ol' the ntaeltirte eontains the lteater to litjttil'y the sugar. .-\s it spins. the head lorees the liquid sugar ottt tltrottglt the tiny holes. When the thin threads ol' sugar hit the air they eool and solidity to lorm a

b

w eh ol sugar threads in the howl ot‘ the maehine. It you mix water with eattdy lloss it dissolyes and you will see that nothing httt a tahlespoon or two ol' sugar tilled the entire hag.

First published in New Scientist’s regular column, The Last Word, and available in a new anthology, published by Penguin. The Edinburgh International Science Festival runs from Fri 1 to Sun 10 Apr. See Around Town listings, page 26, for more details.

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