News
Researchers have uncovered a gene that transmits the itch sensation. The result means that drugs capable of providing the pharmacological equvalent of a "scratch" could soon be on the way, sparing pruritic patients the misery of chronic itch disorders like eczema. Writing in this week's Na...
American astronauts intend to test out a chemical found in the shells of shrimps that may help with healing in case of an accident on a long duration space mission.Unfortunately our human bodies are not well adapted to coping with weightlessness. Our muscles waste away and so do our bones and it eve...
Researchers have found that airbourne pollution can trigger damage to blood vessels. Ke Wei Gong and colleagues, from the University of California at Los Angeles, culture endothelial cells of the type that line blood vessels with particles from diesel exhaust and oxidised phospholipids of the kind a...
Scientists at Northwest University in Illinois have created a super-paper, made of carbon that is tougher than steel, but still more flexible than ordinary carbon fibre. And even better than that, it’s cheap!Carbon has always been known as a fantastic chemical for producing strong materials, diamond...
The Chinese government have announced funding for a large-scale wind farm on the outskirts of Beijing in an effort to cut pollution in time for the 2008 Olympics. The 580 million Yuan (£50million) project, said to be the tenth largest in the world and Beijing's first, will involve the construction o...
Interviews
Coal without the miners and goats fighting chemical weapons - we catch up with Mark Peplow, editor of Chemistry World Magazine
In the UK, this summer has been the wettest on record so far, so what is going on with the weather?
Kitchen Science
Build a camera or if you prefer a magnifying glass, out of some old rubbish and a little water
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Questions

Why does lightning rumble?
If a lighting strike is very close to you it sounds like a very sharp crack and then a bit of a rumble afterwards, the further away you get the longer the rumble can sound. So a lightning bolt will make a sharp short noise, but first of all the noise is produced along a line up to a couple of kilometers long (if you live in Arizona), so because sound travels at 330m/s it could take up to 6 seconds for the sound from the top to reach you so the sound will be spread out over several seconds. The sound is then further spread out as you move further away from the lightning because the sound can get to you directly or by bouncing off things. This means that the sound will take lots of different times to get to you and therefore be spread out over several seconds as a rumble.

Is it possible to have sinus problems without the pain around the nose and eyes?
Normally when you get a cold the reason that you get lots of mucus in the nose is that most colds are produced by viruses. Viruses can only reproduce if they infect one of our cells, when they do this the cell turns into a virus factory and pumps out thousands of new viruses which jump into the cells next door and you get a big area of inflamation which causes the local blood vessels to get leaky and the immune system moves in. You get the sensation of a blocked nose because of this swelling as well as the mucus. This mucus acts as a filter trapping dust bacteria etc. The mucus drains back into your mouth through a series of little tubes called sinuses. Most ways that this can go wrong are inherited, but some are not such as a pollip which is a localised growth of cells which can block one of these sinuses so the mucus can't escape and can build up and cause lots of pain.

Why does my nose go runny when I cry?
When you make tears which come from the lacrimal gland in the eye, they run through a tiny duct into the eye. They then run across the eye to the middle of the lower eyelid where there is a little hole called the puncton through which they drain into your nose. So when you cry you make an excess of tears so there is more to drain into your nose making your snot more liquid and your nose runs.

Would a candle flicker on a hot air balloon?
This would be the case if the wind was completely uniform and moving at a constant speed, because the balloon will get blown at the same speed as the wind so you wouldn't feel it. However if the wind changes speed in a small gust it will take a while for the balloon to catch up with the air and you would feel a gust, or if the wind isn't uniform over the whole balloon you will not be travelling at the same speed as the air near the basket so you will feel some wind. Also a balloon works because hot air is less dense than cold so rises, this means that air around the balloon will get heated up and rise, so the balloon itself will create weak air currents.

How much heavier do deciduous trees get when they grow leaves in the summer?
There are 177 000 leaves on a 48 foot Maple tree which has an area of about 1/6th of an acre - a lot of leaf area. A leaf weighs between 1 and 5g where 5g is for a big leaf like a horse chestnut so if you multiply 5g by 177 000 you get about 1 tonne, about the same as a small family car, not a huge weight as the wood of the tree will weigh a lot more than this. The big problem that leaves pose is their surface area because they trap wind the means that the wind exerts a big force on the tree which is much more difficult to deal with than their actual weight.

How do clouds stay up?
The droplets in clouds are very small things, only about 20microns or 0.02mm in size so it only takes a very small updraght to keep those droplets suspended in the atmosphere. Raindrops are above about 2mm so about 1,000,000 cloud droplets. When they are big enough to overcome the updraught they will fall down to earth as rain.

Does the moon exert an influence on cloud formation?
It is unlikely that it has an influence on individual clouds, as the tides are a tiny effect (they only alter the height of an ocean by less than 0.1%) but they may affect the whole atmosphere slightly by affecting the atmospheric pressure slightly. But the moon is unlikely to make much difference on an individual cloud.

Is the world running out of water?
As we have seen in southern Europe; Greece, Turkey etc. there has been a lot of hot dry weather. The water cycle in the world as a whole is very closed so water can't escape, so we are not going to run out of water. It is possible that the amount of rainfall will decrease, although most predictions say that it will increase, but the areas it is falling in and the times of year it will fall are both probably going to change causing upheavals.

Is this strange weather due to global warming?
You can never attribute a single event on global warming, and most predictions say that we should be getting very dry summers, so it is probably just natural variability in the weather.

Do the cells in a transplanted organ get replaced by your own?
No they definitely won't. Cystic fibrosis is a good example, when you are suffering from it you can't make the right type of ion channel - a pore in the surface of the cells - which means that the mucus gets really sticky and you can't get it out of your lungs easily. If it gets really bad you can transplant new lungs from a healthy donor and this work fine because they have a healthy copy of the cystic fibrosis gene in their stem cells which are making the lung wall cells, so the cells in the transplant work fine.

On a potato shaped object would gravity be the same all over?
Yes, these things are irregularly shaped, because they are not very large, their gravity is not enough to pull them into a sphere, so you are not always the same distance from the mass in the object so the gravity changes. Mars' moon Phobos is irregularly shaped and its gravity varies by about 50% depending on where you are standing which is important for the mission that is headed for this moon. With something this small the gravity is so weak that you want to land on the area with the most gravity or you will tend to float off or at least find it difficult to stay stable, so you may want to fire something like a harpoon into the ground to tie yourself down.

Could you have solar powered air conditioning?
A gas powered fridge is an immensely cunning device invented by Einstein that works by seperating ammonia from water by boiling the mixture then cooling the ammonia to liquify it which gives out lots of heat. This heat can then be absorbed again when the ammonia evaporates in a hydrogen atmosphere a bit like when your sweat evaporates, cooling down the fridge. The hydrogen is then seperated from the ammonia by dissolving it in water which makes an ammonia water mixture to go back to the start.
If you could get the boiler hot enough there is no reason that you shouldn't use this principle to cool buildings, although it would probably involve concentrating the sun with lots of mirrors.
Perhaps a better solution would be to use a stirling cycle engine, this is a form of engine that generates heat by moving heat from a hot place to a cold one, by allowing gas to expand at the hot end and then contract at the cold one. This drives a piston back and forth. So if you concentrated sunlight on the hot end and cooled the other end with air or water you cound generate power which could be used to drive an air conditioner.
All of these processes move a lot of heat from somewhere hot to somewhere warm in order to pump a little heat from somewhere cold to somwhere warm, by far the most efficient solution is to not heat up the building in the first place by painting the roof white and insulating it, or to cool the building by natural convection.

Synethesia and being blind.
There is someone who has perfect pitch because she related the pitch of notes to tastes in a similar way to you, so she could tell exactly which note she was listening to by what it tasted like. Some people can taste shapes for example. We think it is because of some crossed wiring in the brain so when you hear a note the nerves also stimulate the part of the brain that processes taste. Synesthesia quite often gets passed down in families so some of your relatives may be similarly affected. It is unlikely to be related to you being blind as a child.
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