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Kitchen Science
Confuse your sense of touch with this very easy experiment
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Question of the Week
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Could an astronaut skydive from space? Would a spacesuit handle the re-entry heat?
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Why does too much alcohol affect the memory? ...
- WylieE - 2nd Dec 07
with regard to false memories, is it easier to create them in individuals or among a group?...
- paul.fr - 2nd Dec 07
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Questions
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I have two radio-controlled speaking clocks that are identical but one’s two year’s older than the other. They speak at different times. Why is that?
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We're actually not sure about this one!
Most radio-controlled clocks update themselves once a day, but cann't do so if they can't receive a strong enough radio signal. It's possible that one of the clocks has a weaker antenna, and so isn't receiving a signal, and has fallen out of time.
Please let us know if you can think of any other reason for this!
Discuss this in Forum 
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I work in childcare and I’ve wiped lots of bottoms! Is there a difference between bums because it always seems to be harder to wipe boys?
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We're not sure about this one, but we think it could just be that boys are better at making a mess!
If you've got a more helpful answer, please let us know!
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My mother had her leg amputated before she died and I know she suffered greatly with phantom pains. I was interested because the biggest cause of blindness is diabetes. I know a lot of blind people do have amputations through diabetes. I just wondered how this new experiment you’ve been talking about (using a mirror to reduce phantom limb pains) would affect blind people with amputations.
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That’s an amazing point that you’ve made. I think it’s one which, unfortunately, hasn’t been considered in the present research. You’re absolutely right, diabetes is the leading cause of sight loss in countries like this one and unfortunately because the trial they did involved people being able to see it would mean that people that have blindness from diabetes and had had an amputation would have a problem with doing this. It would be difficult. We therefore have to think, ‘is there another way to do what they did?’ It might be that there are ways of using various nerve stimulation to fool the brain into getting signals from the missing body part and that’s definitely possible because a lot of the nerves that supplied the missing body part, the stumps of those nerves, may still be there. It might be possible to do that instead.
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I went to see one of the plasticized human exhibits. [This is where they get a particular organ or system and they effectively fill it with plastic so you’re left with a model of a human system]. I was amazed at the number of peripheral nerves there are in the body. I thought that any injury could easily cut through some of these nerves and I have always been told that nerves can’t regenerate. So if all of these little injuries can damage your nerve then how do nerves regenerate?
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This was asked along with Or's question:
The nervous system is divided into two camps. There is the central nervous system which is your brain and your spinal cord. Then there is the peripheral nervous system which is everything else. The central nervous system (the brain and spinal cord) if you injure that as far as we know, it’s permanent. The nerve cells may die, they may not die but they certainly don’t reconnect where they should connect. That stops signals getting through which is why you get problems of paralysis of loss of sensation depending on where the damage is. That’s why a stroke is so disabling.
In the skin the nerve cells there seem to be able to survive. They also seem to be able to re-grow their targets so they go back to where they should have gone in the first place. They reconnect to, if it was a muscle they were supposed to be supplying, they’ll reconnect with the muscle. If it was a patch of skin they can branch out and re-supply the skin so you do get sensation back. Nerves grow quite slowly, probably a couple of millimetres a day. So if you’ve got a big injury the length of your arm it can take a few weeks before the nerves can get back to your arm. The sensation may not be absolutely perfect because some nerve cells might die but you should get coverage of the skin back afterwards.
What happens when you break the nerve the actual cell inside is just one massive long cell. The distal bit (the bit downstream of the cut site) will degenerate. It retracts and forms this little lump bulb. This thing grows back along the original path of the nerve so it uses the original pathway of the nerve as a guide. Rather like a motorway cone. It uses the cones and lays down a new road surface, which is the nerve, and it gets back to where it was supposed to attach. The distal site it was supposed to attach to switches on various markers so it can recognise it and off it goes!
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Three months ago I underwent surgery to fix a broken collar bone and since then an area just under the surgery site in the skin has become numb. My doctor’s told me that it’s normal and I’ll regain sensation there in a few months. Indeed it is coming back slowly but surely. I thought that nerve damage was permanent and it wasn’t possible to regenerate nerves and therefore get sensation back.
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This was asked along with Micheal Stevens' question.
The nervous system is divided into two camps. There is the central nervous system which is your brain and your spinal cord. Then there is the peripheral nervous system which is everything else. The central nervous system (the brain and spinal cord) if you injure that as far as we know, it’s permanent. The nerve cells may die, they may not die but they certainly don’t reconnect where they should connect. That stops signals getting through which is why you get problems of paralysis of loss of sensation depending on where the damage is. That’s why a stroke is so disabling.
In the skin the nerve cells there seem to be able to survive. They also seem to be able to re-grow their targets so they go back to where they should have gone in the first place. They reconnect to, if it was a muscle they were supposed to be supplying, they’ll reconnect with the muscle. If it was a patch of skin they can branch out and re-supply the skin so you do get sensation back. Nerves grow quite slowly, probably a couple of millimetres a day. So if you’ve got a big injury the length of your arm it can take a few weeks before the nerves can get back to your arm. The sensation may not be absolutely perfect because some nerve cells might die but you should get coverage of the skin back afterwards.
What happens when you break the nerve the actual cell inside is just one massive long cell. The distal bit (the bit downstream of the cut site) will degenerate. It retracts and forms this little lump bulb. This thing grows back along the original path of the nerve so it uses the original pathway of the nerve as a guide. Rather like a motorway cone. It uses the cones and lays down a new road surface, which is the nerve, and it gets back to where it was supposed to attach. The distal site it was supposed to attach to switches on various markers so it can recognise it and off it goes!
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I’ve got a friend who was diagnosed with glaucoma by the optician. What is it and how do you get it?
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The answer to this is it’s not something you can catch, fortunately. Glaucoma seems to run in families. It’s caused by a raised pressure inside the eye. At the front of the eye you produce fluid and this fluid fills the front of the eye and it then gets reabsorbed further back in the eye. The fluid’s continuously being replenished. Sometimes in people with glaucoma, they don’t reabsorb the fluid properly and so the pressure can go up. This puts pressure on the retina, the part of the eye that converts light into nerve signals that the brain can understand. Over time this can damage the retina. In particular, it damages the part of the eye called the optic nerve.
All of the information that the retina sends to the brain, it does so along the optic nerve. There’s about a million nerve fibres in the optic nerve on each side. They run through this structure called the optic disc at the back of the eyeball. You can see this in people’s eyes who have raised pressure; you can see the changes that are very characteristic in this optic disc. If you reduce the pressure with drug then what this does is reduce the severity of those changes. If you catch it early and take drugs you can prevent any damage from happening. Depending upon when you catch it then there can be more or less damage to the eye.
The optic nerve is part of your central nervous system and if you damage the central nervous system then it doesn’t grow back. If you lose a connection or some of the nerve fibres from your retina to your brain then you do lose acuity: the ability to see as sharply as you once did. The longer a problem goes on, the worse it can be. If you have a family history of glaucoma then it’s worth going and seeing an optician just to get checked out.
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| Memory and Learning - More about this podcastThanks for the memory
 The human mind is a mysterious thing, and our brains are capable of phenomenal feats of calculation and learning – although it may not always seem like that! This week on the Naked Scientists we’re looking at what happens when your mind fails you – for example in the case of Alzheimer’s disease, or the creation of false memories.
When memories fail
In 1901, German psychiatrist Alois Alzheimer described the first case of what became known as Alzheimer’s disease – a progressive breakdown of mental function. We now know that the disease is characterised by the formation of protein “lumps”, called plaques, in the brain. But what causes Alzheimer’s? And will we ever be able to cure it?
Joining us to discuss these issues is Dr Peter Nestor from Cambridge University. His research involves trying to marry up images from damaged brains – for example, from MRI scans – with the behavioural problems caused by diseases such as Alzheimer’s. Could this lead to ways to predict how fast people with dementia will go downhill?
 We’ll also be hearing from Professor Ruth Itzhaki, from the University of Manchester. Her research has revealed an exciting link between Alzheimer’s disease and the common virus Herpes simplex, which is widespread throughout the population. Is this virus hiding in our brain cells, waiting to strike?
 Real or imagined?
We all have the occasional moments when our memories fail us – particularly when under the influence of a few pints of beer! But some people have memories of an event that has not happened. These are known as false memories.
In some cases they may be highly damaging – such as false memories of childhood abuse, or eye-witness testimony to a crime. Dr James Ost is from Portsmouth University, and he’ll be joining us to explain where false memories come from, and how his team are trying to separate them from reality. And maybe we’ll try and implant some memories into your brain when you’re not paying attention…
Of course, we’ll also have Question of the Week, where we find out if you can hurl yourself out of a spaceship, clad only in a spacesuit, and still survive.
Now, where did I leave the car keys?
Kat Arney
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