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Science Corner

Tidbits of Science and Technology to wet your appetite

 



How is the steak you ate last night related to solar energy?

Answer Through photosynthesis, basically. Photosynthesis is the process by which plants convert light from the sun into chemical energy – it’s how plants eat. And when animals eat the plants, that energy is passed on to them. Even carnivorous animals that eat only other animals consume energy that ultimately came from the sun. So that's how you fill up on solar energy every time you eat.



Does a millipede really have ten times more legs than a centipede?

Answer Millipedes don't really have a thousand legs, as their name implies, nor do centipedes have a hundred. They both have a lot of legs, but one difference between the two is that millipedes have two pairs of legs per body segment, while centipedes have only one pair per segment. Centipedes may have about 20-300 legs, while millipedes have about 36-400.



How big was the largest shark ever measured?

Answer The largest shark on record – a whale shark – was 12.65 metres long and weighed 21.5 tonnes. But there are likely to be even bigger specimen of this slow-moving, filter-feeding fish - they just haven't been measured.



How many bones are there in the neck of a giraffe?

Answer The giraffe has the same number of neck bones (vertebrae) as you – seven. The reason its neck is so much longer is not due to more vertebrae, but to the fact that the existing bones are a lot longer than yours.



Who has more hair – a chimpanzee or a human?

Answer The density of hair varies from person to person and from primate to primate, but we humans have roughly the same amount of hair as the chimpanzees. Most of it is very fine vellus hair, though, which is much less noticeable than the thick fur of other primates.



Why do we swing our arms when we walk?

Answer Walking on two legs has been compared to 'controlled falling', during which our legs need to catch our forward fall and push us back up with each step. Some of the energy of the resulting bounce gets absorbed when we swing our arms, which means our legs have to do less work. If we hold our arms still as we walk, we require 12 per cent more energy than if we swing them normally.



What's the big deal about sunflowers?

Answer When you buy a sunflower, you're getting a great deal – you pay for one, and you get hundreds! Each sunflower head is not one flower, but a composite of many small flowers, or florets. The ray florets near the rim of the head are sterile but have one large petal each. The disc florets in the center don't look like much but are the ones that get pollinated and form seeds.



How long is a lunar day?

Answer If we are talking about a day on the moon – the time it takes the moon to go through a complete light-dark cycle – it is about 29.5 days, the time it takes the moon to complete one orbit around Earth, since the moon is facing Earth always with the same side. But if we are talking about the time it takes Earth to rotate on its axis with respect to the moon – aka a tidal day – that would be about 24 hours and 50 minutes.



Have you ever seen a gecko wink at you?

Answer Probably not. Like snakes, the most geckos do not have any eyelids, so they can't blink – or wink at you. The do however have a habit of licking their eyes with their well developed tongue.



Did our ancestors live alongside the dinosaurs?

Answer Yes, they did! But they didn't look much like humans yet – more like shrews or squirrels, probably. And only after the dinosaurs became extinct did our ancestors evolve into primate-like mammals, which then eventually led to humans, apes, monkeys, lemurs and tarsiers.



What do elephants chew with?

Answer Unlike humans and most other mammals, elephants have not two but six sets of teeth. And unlike your adult teeth replacing your baby teeth in the same locations, elephant teeth slowly move through the animal's mouth, from back to front, like a conveyor belt. Each chewing tooth can be up to 20 cm wide and weigh 4 kg.



Do we have chameleons in Singapore?

Answer Not in the wild, no. We do have the changeable Lizard, Calotes versicolor, which some people mistakenly refer to as a chameleon. This lizard can change its body colour to some extent, but not as impressively as the chameleon.



Can a lion's tooth make you wet your bed?

Answer The word Dandelion comes from the French "dent de lion", meaning lion's tooth. That's what the French used to call the plant, because its leaves have toothed edges. These days, the French call the flower "pissenlit", or "piss au lit", which means to pee in the bed. This is a reference to the diuretic effect the leaves and root of the plant have when eaten.



How do our taste buds detect the spiciness of chilli peppers?

Answer They don't. When we eat a spicy hot chilli, the capsaicin it contains triggers the heat receptors in our mouth, not the taste receptors. So we literally feel the heat.



Would you want to eat your food twice?

Answer Grass is hard to digest, and rabbits are not able to extract all the nutrients in the first round of digestion. So they (as well as guinea pigs and a few more animals) produce a special kind of faeces containing the half-digested food – the cecotrope – and eat it again for a second round.



Who lives in your belly button?

Answer Lots of microbes, very likely. Our skin is crawling with a whole ecosystem of bacteria and the like, most of which don't bother us or may even be beneficial. Very little is known about the biodiversity of these organisms, and how it differs from person to person, but you are very unlikely to have a sterile belly button.



What do Viking seafarers and honeybees have in common?

Answer They can (or could) navigate by the sun's position in the sky even on overcast days. The Vikings are suspected to have used crystals as polarisation filters – the fabled sunstones – to detect the pattern of polarisation in daylight, which can pinpoint the sun even if it is hidden. Honeybees have such a filter built right into their eyes and are able to use it to find their way around when out foraging for nectar.



Has the Voyager 1 space probe, which was launched in 1977, left the solar system yet?

Answer Not yet; It whizzed past Saturn in 1980 and continued on its path away from the Sun. By now, it is about 16.5 billion km from the Sun, but that is still within the heliopause, the zone that defines the boundary between the solar system and interstellar space.



What is a "ghost particle"?

Answer "Ghost particle" was the nickname given to the neutrino, the elementary particle that has no electrical charge and usually passes right through the atmosphere, you, the planet and out the other end without interacting with anything. That makes it extremely difficult to detect – almost like a ghost... But unlike ghosts, neutrinos have actually been detected.



Which animal kills the most humans every year? (excluding other humans...)

Answer The humble mosquito. There is a whole range of infectious diseases that are transmitted by various species of mosquitoes, and malaria alone causes over 2 million deaths per year.



Can you tell from their tears if someone is very sad or just cutting onions?

Answer There are three types of tears. Basal tears constantly keep our eyes wet and nourished; reflex tears are produced to wash away irritants such as tear gas or onion vapours; and emotional tears flow when someone is sad, in pain, or very happy. This last kind of tears contains protein-based hormones that are linked to the underlying emotions, so they are chemically different from basal or reflex tears.



How long does the shortest pregnancy among all mammals last? (Hint: about 20 times shorter than a human pregnancy...)

Answer In some bandicoot species the young leave the mother's womb after only 12.5 days. However, at that time, they are still very tiny and just enough developed to crawl into the mother's pouch, where they develop further. Bandicoots are small marsupials found in Australia. They look like shrews with large ears and feed on plants, seeds, berries, insects and spiders.



What did Thomas Crapper do to the flush toilet?

Answer He significantly improved its design in the 19th century and promoted sanitary plumbing in a time when most people did not have any bathroom fittings. Contrary to popular belief, though, the word "crap" has nothing to do with Thomas Crapper's name.



Would you eat somebody's stomach contents for breakfast? (Hint: you probably do…)

Answer …if you like honey. Bees produce honey by reducing the water content of the nectar they collect from flowers. They do that by swallowing and regurgitating the nectar, over and over again, before they deposit it in the cells of the honeycomb. The final product contains not only sugars and aromatic oils from the flowers, but also enzymes from the bees' digestive tract.



Ever tried to sleep next to someone snoring? How loud do you think that was?

Answer The average snore reaches between 60 and 90 decibels, which is about as loud as a typical vacuum cleaner. But the loudest snore ever recorded measured 111.6 decibels, which is louder than a chainsaw!



Can an animal live without a mouth?

Answer The Comet moth (Argema mittrei) found in the rain forests of Madagascar is one of the world's largest silk moths, with a wing span of 20cm. The adults of this moth do not have any mouth parts and thus cannot feed. They survive on the reserves they built up when feeding on leaves as caterpillars. However, these reserves last only for 4 to 5 days – enough time to find a member of the opposite sex, mate, and for the female to lay her eggs.



Are you surprised that carrots have been used as an aphrodisiac?

Answer The surprising thing is that it wasn't the root of the carrot plant, but its seeds that the ancient Romans used as an ingredient in concoctions meant to enhance stamina as well as prevent poisoning. At that time, the roots – what we know as carrots – were barely edible. It was only centuries later that selective breeding produced the sweeter and softer carrots we eat today.



Why doesn't our skin dissolve when we soak in the bath?

Answer We have known for a long time that our skin gets wrinkly when we take a bath, because the outer layers of skin absorb water and expand. But only recently did scientist find out why the skin doesn't eventually dissolve: it is held together by a three-dimensional woven pattern of helical fibres of keratin. Like springs, these can be stretched by the expanding skin, but they prevent the skin from falling apart.



If Earth was a 40 year old woman, how long would humans have lived on her?

Answer Less than 18 hours; Earth is about 4 billion years old, and Homo sapiens only appeared around 200,000 years ago. So from the planet's perspective, we humans are like a "24 hour Flu" infection.



Who would be interested in a Basket Stinkhorn?

Answer The Basket Stinkhorn (Clathrus ruber) is a fungus that has a beautiful fruit body but smells like rotting meat. This smell attracts flies and other insects, who then walk all over and feed on the slime that covers the inside of the fruit body and contains the spores of the fungus. Then they merrily fly off and spread the spores wherever they go.