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Science is for
more of us than
just dweebs in
white lab
coats. The
breadth
of events
on at the
EDINBURGH INTERNATIONAL SCIENCE FESTIVAL proves this, and for those who remain unconvinced Mark Robertson gathers together the answers to some everyday mysteries.
I always use blue toilet paper because it matches my bathroom. A friend told me that I should only use white, because coloured paper is more damaging to the environment. Is it true that some varieties are more environmentally damaging?
If your friend means that the dyes are ecologically hannful. forget it. Chemically active groups on the dye molecules cling to the cellulose. which is why the colours don‘t run and leave you fundamentally decorative after you apply them. The dyes are like a mousetrap that has caught a mouse: the mouse. in demonstrating its bite. has become harmless. Much as the trap is hard to reset. the dyes are hard to release from the paper.
Dyes are expensive. and toilet paper requires only traces. so even the most environmentally unaware manufacturer will prefer safe dyes that are simple to handle. and can be applied stingily. typically in parts per million. When the paper reaches the sewage works. the immobilised molecules soon succumb to bacteria. so they do not accumulate in the environment.
Anyway. what about the bleaches necessary for producing white toilet paper? If you really want to be politically correct. go for garbage grey.
In some bars and clubs, the toilet cubicles have an ultraviolet light. I have heard that
16 THE LIST 31 Mar—14 Apr 2005
this is to stop people injecting drugs into their veins. Is this true, and if so, how does it make the veins invisible?
When the blood flow in your arm is restricted. veins distend and are more easily seen 7 they show up as a faint blue line under your skin. This
intense blue light tries to prevent a drug user
from finding veins. because it bathes the area in blue light and the veins disappear. l'nfortunately. the lights only work on the inexperienced drug user and are at best a nuisance for experienced users because there is more than one way to find a vein. When faced with the light. a user will feel for the distended vein or leave the toilet. find and mark the vein. return and complete the job.
Which kind of booze gives you the worst hangovers?
Most people consume alcoholic drinks for their ethanol content. However. many such drinks also contain amounts of other biologically active compounds known as congeners. (‘ongeners
include complex organic molecules such as polyphenols. other alcohols such as methanol. and histamine. They are believed to contribute to the intoxicating effects of a drink. and the subsequent hangover. People who drink pure ethanol-based alcohols such as \odka have been shown to suffer fewer hangover symptoms than those who drink darker beyerages such as whisky. brandy and red wine. all of which have a much higher congener content. Studies have found that the severity of different drinks' hangover symptoms decline in this order: brandy. red wine. rum. whisky. white wine. gin. vodka and pure ethanol.
How many organs can be removed from the human body before it stops functioning well (ie without medical support)?
You can live with only one-third of a kidney and a third of your liver. provided these remain healthy. And. depending on how well they function. less than half of your lung capacity should be enough for you to continue to breathe successfully. ()ne-tenth of your pancreas should supply you with enough insulin and you can part with your stomach. although that would cause some level of dyspepsia. A large portion of the small intestine and the whole of the large intestine and anus can go. If you are an adult. you can say goodbye to your spleen without any dire consequences. You can live without your urinary bladder. Assuming the end product of the removal of the variotts body parts is a person of relatively normal appearance while wearing clothes. and retaining the use of some limbs and senses. but allowing for medication. then our victim may lose toes. the large bowel and most