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Science News
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In a move that could signal an end to bad backs, writing in last week's edition of Nature a team of Australian scientists led by the Queensland researcher Dr Chris Elvin ... |
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Scientists in America have been training 'sniffer wasps' to sniff out explosives, dead bodies and mouldy corn. They trained parasitic wasps, living in a small cup call... |
Kitchen Science

Discover the strange things that happen to a yoghurt pot if you heat it up, and find out what is going on.
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Questions

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Is it true that talking to plants helps them grow better?
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In 1948, a man called Gustav Fechner thought that plants had emotions, so talking tot hem would help you get in touch with your plants and encourage them to grow. Studies also show that music might help plants, especially classical music. However, rock music is supposed to make plants wither away. But apparently this is not the case. If you talk to your plants, you're giving them lots of attention and probably looking after them a lot better. There's also some scientific truth in it. If you got right up close to your plants and talked to them for several hours a day, they'd probably get more carbon dioxide.
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Many years ago I was told that six foot fluorescent strip lights are more efficient and need less energy than tungsten lighting to run. Is this true? If so, how long do they have to be left on before they use less energy overall, so if you flicked on a light for a couple of seconds, would it be better to use the tungsten light bulb or the fluorescent light?
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The way fluorescent lights work is that they contain gas at a certain low pressure, and you fire that gas up by putting a high frequency electrical signal through there. The electricity passing a current through the gas excites the atoms and they lose some of their electrons. The electrons are flicked up to a higher energy level, and then they fall back again to a normal energy level. When they do so, they emit some UV light, which strikes a phosphor, which is on the inside of the tube. That phosphor turns those UV rays into a second form of energy, which is visible white light. This process is very efficient. Tungsten light bulbs work by heating up a piece of metal in a tiny filament until it becomes white hot. Only about 20% of anything they actually use is turned into anything useful.
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What's the difference between fuel sold in the winter and in the summer?
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Fuel is different between winter and summer because the conditions it is used in are different. The starting conditions are particularly different, as engines have to get going from a much lower temperature. What you can do to winter fuel is add chemicals that make the petrol vaporise at a lower temperature, which facilitates cold starting. Using a better mix makes it easier for your car to start on a very cold day.
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If I cut off my finger, why don't cells keep on dividing and give me a new finger? They gave me a finger when I was a baby!
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That's a really interesting question, and it explains why humans are different from things like amphibians. If you cut the tail off a newt, newts can grow back their tails and their limbs. But human cells can't do this, mostly. We do have some cells within our bodies such as in our brain and cells in our skin that do keep on growing. That's why we can heal small wounds. But with something like a finger, there are so many different types of complicated cells, that our stem cells are not capable of making them. They just don't have it left in them to do it. We basically don't have the genes and genetic programme to do it.
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Although saliva is used to start the process of breaking down food, I was wondering if saliva has any healing properties. Cats lick their wounds, and often people instinctively suck small cuts on the backs of their hands. So does saliva keep wounds germ free and help them heal up quicker?
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Yes, saliva does have some beneficial properties because it contains a number of proteins. Those proteins include antibodies, and we make a lot of antibodies when we are infected with various things, and they can mop up bugs and viruses. That's one bonus of saliva. It also contains another protein called lysozyme, and this is an enzyme that can break down some types of bacterial cell walls. When you lick something that has bacteria on it, those lysozymes attack the bacteria and help to neutralise them. Antibodies and lysozyme are also in your tears. Also in your saliva is mucus. Mucus is a protein that forms a sort of meshwork, and it traps things and stops them moving away too fast. So yes, saliva does have a medicinal role too.
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Why does the flu jab only last one year?
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The flu is a nasty virus. It tends to make mistakes when it copies itself, so that when the virus made in one person is passed onto someone else, it is slightly different to the one you were infected with. As the flu goes around the world every year, by the time it's got back to where it started, it looks very different from the version that was here before. When you get the flu the next year, your immune system cannot recognise it because it looks completely different. So a vaccine is only good until the flu changes, which is why you have to have a new jab every year.
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Why do insects have more legs than humans?
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I think if you're small animal, it's quite hard not to fall over. So if you have a large number of legs you can stay on the ground more of the time. So essentially, insects have more legs than humans because if they had less legs, they would fall over very easily.
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I read an article saying that propolis was good for the immune system. My husband has rheumatoid arthritis, and this attacks the immune system. I was wondering if taking propolis would be any good in this respect.
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Actually rheumatoid arthritis is the immune system attacking joint tissue, which it shouldn't do. So it's the immune system going out of control. I don't think it would do him any harm at all. Whether it would do him any good, I couldn't really say. There have been many claims made, but not many have been substantiated I don't think.
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What is the most powerful insect, and can fly the furthest?
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In a single stretch, I probably think it's the dragonfly. These animals spend most of their life on the wing and they just come down to settle to look to see where the prey is. They can fly for quite long periods. There are many insects that have been found several hundred miles off of the coast, so lots of things can fly for long distances if they get caught by the wind. I think the insect that can fly the furthest under its own steam is probably the little biting black flies, which you get in West Africa. They can do 300 kilometres while looking for prey. The most famous migrating insect is the monarch butterfly, which flies across North America to special roosting sites in Mexico. That's a very famous, powerfully flying migrating butterfly.
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| Interviews
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Ian Burgess from Insect Research and Development, Cambridge
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Megan Frederickson from Stanford University, California
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Bee Wilson, historian, food columnist and author of The Hive
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Dr William Foster from the Department of Zoology, University of Cambridge
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Fact or Fiction
Fish hear through their bodies
 
It's True - Most fish
have two "inner" ears with no direct fluid connection
to their environment. The fish ear contains bony structures
called Otoliths which are covered in tiny hairs. The difference
between the motion of the fish in the water and the Otoliths
stimulate the hairs and this movement is interpreted by
the fish as sound.
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The spleen is an organ in your abdomen that helps with
digestion
 
It's False - The spleen is a fist-sized organ
on the left side of the abdomen, but it doesn't help digest
food. It actually helps the immune system to recognise
and fight infections.
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Glass comes from volcanoes
 
It's True ·
You can find examples of natural glass in volcanoes where
it is called obsidian.
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Duck billed platypuses are the only mammal in the world
that lays eggs
 
It's False - Another antipodean inhabitant,
the echidna or spiny anteater also lays eggs, and belongs
to the same group of mammals as platypuses, known as monotremes.
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Mosquitos flap their wings about 600 times a second
 
It's True · This produces the irritating
whining noise you can hear when you are trying to get
to sleep at night and a hungry mosquito has got into your
room.
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A blink lasts approximately 0.3 seconds
 
It's True
- If you are driving at 60 miles per hour and you blink,
you will be driving nearly ten metres blind!
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You can see the Great Wall of China from Space
 
It's False · Mathematically it is impossible. Despite
its spectacular length, the wall is only about 5 metres
wide, meaning that even a person with perfect eyesight
would struggle to pick it out from only about as far up
in the air as 60,000 feet, or twice the height of mt Everest.
Since this is still way below the altitude at which a
space craft can orbit, it·s safe to say that it·s
a myth that it is visible from space. Perhaps the best
evidence is the testimony of Apollo astronaut Neil Armstrong
who confirmed that the wall is not visible from space.
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Rhinoceros horns are made of highly compacted hairs
 
It's True - Rhino horns are made of the same stuff as
hooves and hair, with hair like strands compacted so closely
together they form a very tough almost bone-like material.
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Boa constrictors, a kind of snake, can reach 30 feet
in length
 
It's False · These South American
snakes usually reach 12ft in length and up to 40lbs in
weight. They live in hollow logs and mammal burrows and
eat possums and bats which they kill by wrapping around
their bodies and suffocating them before swallowing them
whole.
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