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15th Jul 2007
Fuels of the Future
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This week, from iPod to iRod as a man's taste for music turns him into a human lightning conductor, why penguins are picky eaters, and better biopsies - why doctors are attracted to a new magnetic cancer detection system. Also a fuel made from fructose that packs a punch like petrol, we find out how to make hydrogen on demand using aluminium, and grow your own gas - do we have enough land to grow our energy in future? Plus, in Kitchen Science, we turn vegetable oil into biodiesel and ask a white van man to test it...
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Science News
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A paper in this week's New England Journal describes a man admitted to hospital with a rather strange pattern of skin injuries including ruptured eardrums, a broken jaw and burns to his chest, neck an... |
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Penguins living in the Antarctic have changed their minds about their favourite food, a change of diet that could have been triggered by the hunting of whales and seals over the last two hundred years... |
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For the first time researchers have been able to say with certainty that there is water on a distant planet.
Writing in this week's Nature, UCL's Giovanna Tinetti and her colleagues used NASA's Spit... |
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There was good news this week for lovers of muck and magic, because it seems that organic farming could be capable of producing enough food to feed the world.
That’s according to a study from team of... |
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Researchers at the University of New Mexico and Albuquerque company Senior Scientific are testing a new breed of iron oxide-based magnetic nanoparticles that are encased in a biocompatible coating. Th... |
| Interviews
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Jerry Woodall, Purdue University
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Jim Dumesic, Wisconsin-Madison
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David MacKay, Cambridge University
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 Prof. Matthew Davidson, Prof. Gary Hallway & Chris Chuck, University of Bath
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Chelsea Wald and Bob Hirshon, AAAS
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Questions
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Why, when I yawn, do tears come to my eyes?
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When people yawn, they tend to tightly shut their eyes, and this does two things. First it squeezes the lacrimal duct, causing more tears to flow into the eye. Secondly it squashes closed the tear ducts that drain the tear film from the surface of the eye. As a result there are more tears in the eye and nowhere for them to go. So when your yawn ends and you open your eyes again they are watery.
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As lightning comes down from a cloud, does a positive charge go up to meet it? Is this what throws people up into the air?
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Like charges repel and opposite charges attract. So when there’s a concentration of negative charge in a cloud, such as just before a lightning strike, negative charges in the ground are repelled and move away, leaving a positively charged ground. When these charges attract each other enough, the lightning overcomes the natural resistance of the air and discharges as a fine thread of lightning, usually only about 1 cm across.
People are thrown around when struck by lightning because of their own muscles, in a process called opisthotonus – sudden catastrophic muscle contraction. When the electricity runs through the body, all of your muscles contract at once. The strongest muscles in the body are the ones which hold you upright, so you are thrown off the ground.
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Can you harness the electricity in lightning?
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There are 2000 thunderstorms going on at any one time around the earth, this equates to about 100 strikes every second. The average lightning strike unleashes the same energy as about a tonne of TNT. This could be about 1 billion Joules of energy – if you consider a 100W lightbulb in comparison:
A 100 W lightbulb uses 100 J of energy every second, which is 360,000 J per hour, or about 9 million J per day. This means that with the energy from 1 lightning bolt could light just 1 100 W lightbulb for 100 days.
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Which is the best way to boil water for a cup of tea, on an electric stove or in a microwave?
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There are many answers depending on what you mean by better for a cup of tea! But we at the Naked Scientists think that the microwave method might be quite dangerous.
Microwaves ovens emit microwaves, and these form a standing wave inside the oven. This means that certain areas heat up faster than others. This can superheat pockets of water to hundreds of degrees, as the pockets are held in by the surrounding water. When you remove the water form the microwave and stir, these pockets can suddenly expand, and this could result in showering you with boiling water.
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When I clean the ear wax from my ears using a q-tip, I tend to feel an urge to cough. Is this a common reflex? Am I pressing on a ‘coughing nerve’ with the q-tip?
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There is a cough-ear reflex, but only 2.3% of the population experience it. There’s something called Arnold’s nerve, part of the vagus nerve which supplies the head and neck. It supplies the back and lower floor of the external auditory canal – the tube towards your inner ear. If stimulated, this nerve can provoke a coughing reflex.
Although only 2.3% of people experience this in one ear, only 0.6% get it in both!
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When I ride a lawnmower, it vibrates a lot. After I get off, my feet feel like they are vibrating, even though the ground below me is not vibrating.
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This is because of a quirk in the way your body processes incoming sensory information. We have a process called adaptation, where if we experience something all the time, the nervous system shuts off the sensitivity to that thing, to avoid sensory overload. For example, if you visit someone’s house, you immediately notice a smell, but after you have been there for a few minutes, you stop noticing. Our bodies are only interested in things that change, so if you are in the jungle, you would need to pay a lot of attention to the smell of smoke if it suddenly arrived. If you were constantly experiencing the smell of all the trees and soil around you, would wouldn’t be as able to pick out the smoke.
The same thing happens on your lawnmower – the vibration is there all the time while you’re mowing. The body suppresses it’s sensitivity to the vibration. When you take the vibration away, they body is suppressing something which isn’t there, and so you feel the inverse of what your nerves were trying to cancel; in this case, you feel like your feet are vibrating.
The same thing happens when you’ve been on a boat for an extended time, you get back on land and still have ‘sea legs’!
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Aren’t hotspots in a microwave oven only a problem when there’s no rotating base for the food to sit on?
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That’s true to a certain extent, but humans love doing things symetrically. We tend to put our food or drink in the centre of the turntable, which means you can still get hotspots right in the middle.
The best way to microwave something is to put it on one side of the turntable, so that it goes through lots of hotspots and is evenly cooked.
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