Penguins feet - and other stuff
|Every had a child ask you a dreaded question, like, "How does a squirrel find its buried nuts?", or "What time is it at the North Pole?". Well, help is here .... read on!|
Q1: Why don't penguins' feet freeze in the winter?
A: Penguins reduce blood flow to their feet by varying the diameter of arterial vessels. This keeps their feet a degree or two above freezing, minimising heat loss, while escaping frostbite.
Q2: Why is water wet but mercury 'dry'?
A: Atoms stick together in different combinations to form molecules. Each water molecule is made up of two atoms of hydrogen and one of oxygen. When you get many molecules of water together they not only pull on themselves, but on any molecule they come in contact with. For example, your skin. Other liquids, such as Mercury, pull harder on themselves than other molecules. That is why water is wet and mercury 'dry'.
Q3: Why do stars 'twinkle'?
A: Starlight reaches us by passing through the atmosphere which has an effect upon what we see. Think of the shimmering on a hot road in summer. The atmosphere is full of pockets of air which are distorting the light we see. This is why the Hubble telescope needed to be outside out atmosphere so as to produce 'twinkle'-free observations.
Q4: How many stars are there?
A: On a clear night, with good eye-sight, a person might see about 6000 stars. But there are something like, 100,00 million stars in our galaxy - the 'milky Way', and about 100,000 galaxies. So there are quite a lot of stars out there!
Q5: Are shooting stars really stars?
A: No, they are small, solid pieces of dust and debris, usually from the tails of comets. These particles strike the Earth's atmosphere at such a high speed that they burn up and produce the trail of light that we call a 'shooting star'. Larger particles may reach the Earth's surface before burning up completely. These are called meteorites.
Q6: Why is there no air in space?
A: Each planet, moon and star has gravity which holds any air molecules close to their surfaces and so it does escape into space. Any air molecules that were released into space would soon be drawn into the gravitational effect of some planet or other.
Q7: Why do sounds like the scratching of a blackboard make people shiver?
A: The warning sounds emitted by some great apes are of a similar frequency and tone as the sound of fingernails on a blackboard, so possibly there is a primal link to a danger instinct (if you are a Darwin fan of course!)
Q8: Can you prevent your eyes watering when peeling onions?
A: Onions contain a type of amino acid that forms a mixture of sulphuric acid and hydrogen sulphide when it comes into contact with your eyes. To prevent your eyes watering, slice the onion under water, or, before slicing the onion, wash it and keep it wet. Both actions dilute the acid. Alternatively, wear swimming goggles!
Q9: Why do bubbles in a bubble bath disappear if you use soap?
A: Interestingly there are a couple of theories about this one. The popular view which can also be found on the New Scientist web site is that Bubble Bath and Soap are opposite types of chemical components called surfacants. The bubble bath surfacants are positively charged while those of soap are negative. When they mix the foam collapses.
However, Robert Goodman was kind enough to email this to us. "Soap and bubble bath molecules are NOT oppositely charged. Soap breaks bubble bath foam in the presence of, and ONLY in the presence of, free "hardness" cations in the water. Where water is fully "soft", soap does not break bubble bath foam. The same "lime soap" that forms bathtub ring from "hard" water is also a potent defoamer. Soap has even been used in some liquid detergents as a suds control agent, in the assumption it won't be used in fully "soft" water.". Robert's a bit of an expert on this so check out his web site at: http://users.bestweb.net/~robgood/lather.html.
A: A typically modern 7.63mm bullet would be fired at 840 metres-per-second (ms), reaching a height of 2400m in 17 seconds. It would then take 40 seconds to reach the ground, at a final speed of 70ms. Because such injuries usually involve the head, the number of deaths and serious injury as a proportion of gunshot wounds generally, is surprisingly high - 5 times more than in normal firing.
Q11: Why do your fingers and toes go wrinkly after a time in the bath?
A: The tips of fingers and toes are covered in a tough, thick layer of skin which, when soaked for a long time, absorbs water and expands. However, because there is no room for this expansion the skin buckles, hence the wrinkles.
Q12: What is a hiccup?
A: There is no known function for the reflex we call a hiccup. Low levels of carbon dioxide in the blood make hiccups worse, suggesting their function may be to control breathing. Holding your breath presumable stops hiccups by raising the concentration of Carbon Dioxide in the arteries.
Q13: Why can't you tickle yourself?
A: Tickling causes tension for most of us because of feelings of unease due to physical contact, lack of control, anticipation or perhaps fear of being hurt. But when you try it yourself, you are in complete control, there is no anticipation and no need to be tense. If someone were tickling you and you were able to stay calm and relaxed, it would not affect you.
Q14: If the Sun is a star like any other, why does it look yellow rather than white?
A: Stars come in many different colours, which are linked to temperature. Young, hot stars are white, while older stars are red. Our sun is a medium sized star burning at a medium rate, hence its yellow colour.
Q15: Why is it that a warm bath (102f/39c) is relaxing but a room at the same temperature is stressful and uncomfortable?
A: The bath water may be at 39c, but the bathroom is probably much cooler allowing the body to lose excess heat. In contrast, a room at 39c causes heat to flow into the body and body temperature increases. This causes the stress and the brain takes action, like encouraging cold liquids to be drunk, or the room to be exited!
Q16: What time is it at the North Pole?
A: The International Date Line runs through the North Pole, leaving it eternally between one date and the next. In other words, it is always officially midnight at the Pole.
Q17: If you run through the rain will you get less wet than if you walk?
A: The number of raindrops falling on you depends upon how long you are out in the rain. So if you run, presumably you will be out in the rain for less time. However, by running you will get more rain on your head in a shorter time and thus be wetter. So generally, if it is a light shower, walk, but run in a heavy downpour.
Q18: How do they get a grown pear inside a bottle of Poire William liqueur?
A: Bottlers go into the pear groves and place empty bottles over the pear buds. The pears grow into the bottles. When nearly ripe they are picked and the bottle filled with liqueur.
Q19: Is it true that you catch a cold after getting cold?
A: No. You get more colds in winter because the viruses which cause them spread faster as people spend more time close together inside buildings. People also close windows, so air with virus particles in it is not diluted by fresh air, thus making it easier for the virus to spread.
Q20: Why do people have finger prints?
A: The patterns of whirls and ridges which we call finger prints, help use to grip and handle objects. They work on the same principle as a car tire or climbing boot. Smooth surfaces can grip in the dry but in the wet the finger prints channel water away from the grip area and thus gives a good overall gripping surface.
Q21: How does a squirrel find the nuts it buried?
A: Squirrels have a good spatial memory and make a mental map of where they buried the nuts, remembering landmarks and the environment. They also use their acute sense of smell to help them locate their food.
Q22: Do penguins fall over when planes fly over them?
A: This is a popular urban myth. Penguins do not fall over backwards while looking at planes flying over them. Google this question for more info.
If you've enjoyed these little gems, there is more of the same to be found in the book, "The Last Word" edited by Mick O'Hare (Oxford University Press) and available from:
Amazon online books.
All original material ©2000 The Curious? Web Site