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Frequently Asked Questions
All of the questions listed below were originally sent to the SchoolsOnLine
Question: What is the average life span of a sugar maple? Is there any way to estimate its age by its height? Are sugar maples hardwood or softwood trees?
Answer: The sugar maple, Acer saccharum, is an important source of maple syrup and is grown particularly in the north eastern United States. In response to your first question, the true average life span of any tree species is difficult to determine. The number of individual trees dying at the difficult sapling stage, for example, may be high, and if the figures for these losses were to be included the average life span may seem unreasonably low. The final age of any individual tree will depend on a number of very variable factors such as soil depth, rainfall, competition, disease and human activity.
200 year-old sugar maples are known and I am sure that there are older individuals.
It is also quite difficult to estimate the age of a sugar maple by its height since the rate of growth will depend on a number of environmental factors. Once maximum height, which is usually about 30 metres but may be as much as 37.8 metres, is achieved it will remain unchanged and the tree will only increase in diameter as it gets older.
For further details on the two above questions I suggest you contact forestry organisations or those representing the maple syrup industry.
I can tell you quite definitely that the sugar maple is a hardwood tree, in fact the wood from a sugar maple is very dense, hard-grained and light coloured.
Question: Certain birds of prey swallow their food whole. The gizzard compresses some parts into a hard pellet. Which body parts do you think these pellets contain?
Answer: The pellets of which you write are formed from compressed indigestible materials, those which cannot be digested and used in metabolism by the birds of prey. The pellets usually consist of bones, feathers, fur or hair and possibly fish scales. The fragments found in the pellets of different birds can tell us much about the feeding habits of the birds in question.
Question: Do penguins have jointed legs? If they do why do they walk around with stiff legs?
Answer: I contacted a zoo where they have a collection of penguins to confirm my thoughts on this question. The simple answer is yes, penguins do have jointed legs. Although you may not be able to see them, perhaps because of the folds of abdominal skin that penguins often have, they do have ‘knee’ joints.
The way in which penguins walk is related to a number of factors. Their legs are relatively short and they are set far back on their bodies. This is why penguins, unlike most birds, have such an upright posture. Taking small, seemingly stiff steps may aid balance. I would also imagine that taking small steps would be to the advantage of a bird which often lives in very slippery conditions. I certainly take very tentative steps on ice.
Penguins can travel long distances overland. Rookeries (nesting sites) of the adelie penguin, for example, may be 50 miles from the sea and the penguins have to travel for 24 hours between feeding and reaching the nesting sites. In addition to walking penguins may often slide or ‘toboggan’ over the ice, propelling themselves forwards using their feet and their flippers. As their name implies, the very agile rockhopper penguins, often jump from stone to stone with their feet together.
It is thought that the short legs of the penguin are also useful when the penguin is standing still. The feet and the tail act as a tripod to hold the penguin upright for long periods without making the bird very tired. Remember that having short legs also cuts down the amount of heat lost through them, a consideration very important when you think about the extremely cold conditions in which most penguins live.
It is in water where the penguins are most agile. Here their short legs with their flat, webbed feet are used as rudders. Because the legs are set well back they carry out this function effectively.
Question: I heard about a gigantic tsunami which covered the United States about 100,000 years ago. First of all, is it true? Then if it is, how can I find out more?
Answer: Research indicates that there was a giant tsunami in the Pacific Ocean some 105,000 years ago, caused by either a submarine landslide, volcanic activity, an earthquake or possibly a meteorite impact. The enormous submarine landslide theory is considered most likely, with these types of landslides having been proven around the various islands of the Hawaiian chain.
Jim Moore, a vulcanologist with the US Geological Survey, has studied these landslides for over thirty years, mapping of the sea floor around the Hawaiian Islands having proven the presence of many of these submarine landslides. These slides were on such a large scale as to be thought able to cause massive sea displacement and accompanying earthquakes as the slide occurred, this in turn producing tsunamis around the Pacific. These types of slide, both on land and at sea, have been christened ‘long run-out landslides’.
On the Hawaiian island of Lanai, sediments containing fragments of coral and sea shells have been found mixed with the volcanic rocks at an altitude of some 375 metres (1,230 feet). Carbon dating of these fossils has yielded ages of about 105,000 years. The height of the postulated tsunami to produce this occurrence must have been huge. Again, submarine landslides have been proven around Lanai and some sort of massive ‘back-wash’ could possibly have deposited these fossils in such an incongruous position.
In Australia, research by two geographers (Bob Young and Ted Bryant) at the University of Wollongong in New South Wales has found supporting evidence for an enormous tsunami which hit the coast of east coast of Australia some 105,000 years ago. Large-scale erosion features have been found in the coastal areas which cannot be explained by current waves and tides. These eroded channels all align in the same direction and all indicate a wave approach from the north east - in the direction of HawaiiI am sure as continued research progresses that further evidence in support of a giant tsunami at this time will found. Smaller but younger tsunamis are already being proposed based on the research of Young and Bryant in Australia.
So, yes, the existence of a gigantic tsunami in the Pacific Ocean around 105,000 years ago appears to be very probable. However, such a tsunami, even though enormous in relation to more recently recorded ones, would not have been of sufficient size to have ‘covered the United States’. It would certainly have caused catastrophic damage along the west coast of the US, but it would not have progressed that far in land, particularly due to the presence of the west coast mountain ranges. It would also have devastated islands and coastal areas all around the Pacific and even beyond. And as mentioned already, the hottest theory of the cause of such a tsunami is an enormous submarine landslide in the Hawaiian Islands - but a meteorite or asteroid impact in the Pacific Ocean can also not be ruled out.
As far as finding out more about this amazing event, whatever its cause, I can only suggest that a trip to a geologically orientated University library or contact with the US Geological Survey would be a good place to start.
Question: In cold climates, where do turtles go in the winter?
Answer: Marine turtles, such as the green turtle, can migrate into warmer waters in cold conditions. It is known that these migrations can be incredible journeys of many hundreds of miles.
Other turtles have to cope with the changes in the climate by different means. Many turtles may be said to hibernate during cold or otherwise adverse conditions although this is not strictly correct because hibernation only really relates to homeothermic or ‘warm-blooded’ animals which lower their body temperature during periods of hibernation. Since turtles are reptiles and are poikilothermic or ‘cold-blooded’ animals they do not truly hibernate but may enter a state of torpor or inactivity when conditions are not favourable.
One example of a turtle which goes into a state of inactivity in certain climatic conditions is the box turtle which is found as far north as New England and as far south as Mexico. The box turtle buries itself about 6-10 inches deep in soft soil or mud and, with a decreased rate of metabolism, may stay underground long enough to avoid extremely cold temperatures. If the winter is mild then it may only stay inactive for a few months between December and March. This type of turtle may also go underground in a similar way during very hot, dry weather in order to conserve water. Other turtles may take shelter under mud or piles of vegetation to avoid adverse conditions.
Some types of turtle may survive relatively mild cold spells by staying under the surface of the water in ponds and ditches. The soft-shelled turtle can sit at the bottom of a pond and breathe air from the surface because of its long, flexible neck as long as the water remains unfrozen.
To find more information on this subject I advise you to look at some reference books relating specifically to turtles and other reptiles. You could also contact organisations concerned with the welfare and conservation of these creatures.
Question: How does fingerprinting work? There are different types of fingerprints; what are they called and how are they different?
Answer: Fingerprinting is thought to have been used first by the Chinese in the eighth century BC as a means of verification of legal documents. They were first used for identification in a systematic way in the 1800’s.
The skin on the fingertips of a person’s hand has a distinctive pattern of ridges which is unique to that person and remains the same throughout the person’s life. Sir Francis Galton developed a system for the classification of fingerprints which was first used regularly in 1891.
To keep the classification relatively simple for our purposes I shall only mention that there are three main types of fingerprints. These are the arch, the loop and the whorl. The ridges in an arch, not surprisingly, form an arch shape. A loop is rather more elongated than an arch and may be at quite an angle on the fingertip. A whorl is like a number of concentric closed circles.
When someone has their fingerprints taken they press the tips of all their fingers on a pad soaked in special fingerprinting ink. They then roll each finger gently from one side to the other on paper or another suitable surface. These prints may be then compared with others, for example those taken at the scene of a crime, or they may be classified and stored in archives ready for future comparisons. Detailed classification makes it easier to narrow down stored fingerprints for comparison whenever the need arises. Computers are being increasingly used for the analysis, classification, storage and comparison of fingerprints.
If you have fingerprinting ink in the science department of your school you can make copies of your own fingerprints. Be careful with this though because it can get really messy! It is interesting to classify the types of fingerprints obtained from a class and it can be done quite easily with magnifying lenses or binocular microscopes. I usually get at least one extra print from each student. These remain unidentified and are mixed up an are handed back to the students for comparison and identification.
Question: What determines the path a tornado will take?
Answer: In its most familiar form, a tornado is a funnel-shaped, vaporous mass, with winds rotating around a vertical axis at high speeds, which reaches down from a thundercloud o a squall line.
Violent storms often break out in central and southern states of the USA in springtime, when waves of warm, moist air from the Gulf of Mexico moving north and north-west, clash with invasions of cooler dry air coming down from the north and west. The month of May has the highest frequency of tornadoes, although April twisters tend to be more severe and take more lives. There are some 100,000 thunderstorms a year in the USA but only 1% spawn tornadoes. Of these, only 2% cause 70% of the deaths.
A tornado takes its direction - usually from the south-west to the north-east- from the movement of the parent thunderstorm cloud. The funnel advances at forward speeds that average about 30 miles per hour, but may exceed 70 miles per hour. The tornado may bounce and skip, rising briefly from the ground and then touching down again, and it can sway from side to side, sometimes tilting forward and sometimes back. Whatever track it eventually takes, whether it be straight or sinuous, the tornado belongs to the parent thunderstorm cloud and basically has to follow.
Although some rare twisters wreak havoc for hours, their lifespan is usually less than 15 minutes on average. A typical tornado descends from a severe thunderstorm as a crisp white funnel cloud. When it reaches the ground, the twister is affected by friction, quickly turns grey and black due to sucked in dust and debris and soon develops ragged edges. In the end, a tornado in effect becomes clogged with air and debris and its base is slowed by its contact with the ground. Although it can still generate swirling winds, a weakening tornado can no longer suck up the air in its path and gradually lags behind its parent thunderstorm. The funnel stretches out into a sinuous, ropy shape and begins to collapse, eventually dissipating completely.
Question: What would happen to the human body if it travelled down into the deep part of the ocean zone without special equipment? I know the pressure is great, bit I want to know if out organs stop working or if our body would collapse, or would it explode?
Answer: Normal atmospheric pressure at sea level, which is approximately 100,000 N/m2 (newtons per square metre), is caused by the weight of the atmosphere pressing down above us. At any given depth below the surface of the sea the weight of the atmosphere and the weight of water above that depth combine so the pressure on divers increases as they go deeper because of the increasing weight of the water above them.
The pressures deep in the ocean are certainly extremely high. It has been calculated that at about 90 metres depth the water pressure is approximately ten times greater than normal atmospheric pressure. I shall leave you to calculate how much greater the pressure will be in the deepest part of the ocean which is thought to be in the Marianas Trench in the Pacific Ocean. A depth of 10, 911 metres has been recorded there!
There is obviously a limit to the depths that divers can go in the sea even with special equipment such as strong, jointed metal suits to protect them. Without special equipment divers would soon experience problems due to the increased pressures under water. Just diving down to the bottom of a deep pool can cause discomfort to the ears as water presses in onto the eardrum or tympanic membrane.
Water pressure acts in all directions and would exert pressure onto a diver from above, below and from all sides. As greater depths were reached the body would be crushed and eventually all major organs would cease to function. Breathing below certain ocean depths, even though suitable air may be supplied, is impossible without special apparatus because the surrounding water pressure is too great to allow the muscles to raise the ribs and expand the chest cavity in order to draw air into the lungs. I have read that the lungs of whales can collapse when they are on deep dives. There is some evidence that the sperm whale may be able to dive to a depth of over 3,000 metres.
In summary, yes, if a human body travels down into the deep part of an ocean without special equipment the body would ultimately collapse and the organs would stop working because of the effects of pressure caused by the large weight of water above the body.
Question: What are blood transfusions? What actually happens?
Answer: Transfusion is the process of transferring blood from a donor into the body of a recipient. Usually the donor and recipient are different people although it is possible to take blood from one person and give it back to them later when they need it for example after an operation.
The term ‘blood transfusion’ does not always mean that a recipient is receiving whole blood but this may be given in cases of severe blood loss and is blood with all the constituents it contained when donated although some of the clotting factors may have become less active during storage.
In other cases the blood which is donated is tested then separated into its components which may be distributed to hospitals when requested. The components of blood which may be transfused are:
Usually whole blood is taken from a donor although it is possible to quickly remove the plasma from donated blood and return the rest of the blood to the donor. This process is called plasmapheresis.
During a donor session about 0.5 litres of blood is drawn from the arm into a plastic, sterile pack which contains a solution designed to stop the blood clotting. The whole process of donation usually takes about 45 minutes. Blood is insfused into a recipient through special sterile giving sets and usually enters the body via the veins of the hand or forearm. Gravity plays a role here but the rate of infusion can be carefully controlled.
If you wish to find out further information do contact the National Blood Service through your regional transfusion centre.
Question: Does the size of a person's bladder affect the length of time it takes to urinate? Will a person urinate more if they drink a cup of milk, a cup of soda or a cup of water?
Answer: I think it is reasonable to say that in general it takes longer to empty a large full bladder than it does to empty a smaller bladder which is also full. Remember though that people can urinate before their bladders become full and it will probably take approximately the same amount of time to expel, for example, 300cm3 urine whatever the size of the bladder.
The bladder is a collapsible bag which spreads into the abdominal cavity when full. An adult bladder can hold a maximum of about 800cm3 urine but the average adult bladder holds about 500cm3 urine. Usually, when the volume of urine in the bladder reaches about 300-350cm3 stretch receptors in the bladder wall cause a message to be sent to the central nervous system that it is time to urinate but, as you will doubtless be aware, humans can put off urinating for some time until the pressure of the urine in the bladder becomes too much to resist! They can also urinate before the bladder becomes full.
I don’t think that there will be any real difference in the amount of urine produced if a person drinks a small volume, such as a cup, of any of these substances. One thing that might make a slight difference is whether or not the soda contains caffeine (a chemical also found in many coffees and teas). Caffeine is a diuretic, which means it can cause an increase in urine flow and make people urinate more so, in theory, a drink containing caffeine will make people urinate more than one without caffeine. Neither water nor milk contain caffeine.
It is also true that a cup of milk contains more solid material and therefore less water than a cup of drinking water so more urine should be produced by drinking water rather than milk but I really don’t think there would be any significant difference with these small volumes.
Question: Could you assist me in finding information on green pigments other than chlorophyll?
Answer: This is an interesting question. First we have to remember that there are many different chlorophylls. Most of the green plants with which we are familiar contain chlorophylls a and b. Brown algae and diatoms contain chlorophylls a and c, red algae contain chlorophylls a and d and chlorophylls a and e are found in yellow-green algae. The colours of the different chlorophylls are described below:
Bacteriochlorophylls are similar to the chlorophylls mentioned above but differ a little in chemical structure. Unfortunately they are described as blue pigments so not very useful here.
I haven’t found any references to other green plant pigments but I hope this information is of use to you.
Question: Why do we yawn when someone else yawns?
Answer: Yawning is a partially involuntary action. This means it can happen without us really thinking about it but we can also make ourselves yawn in some circumstances.
Most of our breathing movements are controlled by the breathing centre, which is situated in the medulla at the base of the brain. This part of the brain controls the involuntary actions of the body which we don’t usually have to think about in order for them to happen, such as breathing and heartbeat.
The conscious or thinking part of the brain, the cortex, is connected to the medulla and it can send messages to the breathing centre by which it can consciously control the rate of breathing. You will know, for example, that you can choose to slow down or speed up your rate of breathing whenever you want.
When we are resting and breathing slowly our lungs sometimes do not get rid of enough carbon dioxide so this builds up in our blood. This build up of carbon dioxide is detected by receptors and the breathing centre sends a message to the muscles around our lungs to take an extra deep breath which blows out excess carbon dioxide and brings more oxygen into the lungs. This extra deep breath is the yawn. Often a yawn can take us by surprise and sometimes we hardly notice that we are yawning. On the other hand we can also make ourselves yawn just by thinking about yawning.
When someone else yawns it is often very difficult not to yawn in response. Basically what is happening is that a type of auto-suggestion is taking place. Just thinking about yawning can make us yawn. When we see someone else yawn the conscious part of the brain thinks about yawning and this makes it send a message to the breathing centre. The message from the cortex causes the breathing centre to trigger the yawn response. It is possible to override this response and stifle the yawn but it isn’t always easy to do so!
Question: Why is limestone (sedimentary rock) found on the top of a mountain in Wyoming?
Answer: Limestone is a sedimentary rock and was originally deposited at the bottom of ancient seas and oceans millions of years ago. The fact that these same limestones and other sedimentary rocks can be found at the top of a mountain in Wyoming, and even high up in the Himalayas, is the result of something called PLATE TECTONICS.
It has been discovered that the whole of the Earth’s surface (on land and under the sea) is made up of interlocking blocks of the Earth’s crust which are called ‘plates’. These plates move around over the planet, either moving away from each other, rubbing against each other or colliding with each other. The earth’s crust under the sea is thin an known as ‘oceanic crust’. On land it is thick and known as ‘continental crust’. Where oceanic crust collides with continental crust, mountain ranges with many volcanoes are produced (such as the Andes) and where continental crust collides with continental crust massive mountains (such as the Himalayas and the Alps) are the result.
This mountain building is a very long process. The Himalayas began to be formed about 40 million years ago as the Indian ‘plate’ moved northwards and collided with the Asiatic ‘plate’. As India moved northwards, vast amounts of sedimentary rocks in the seas, (such as limestones and sandstones), were pushed and squeezed in front of it. As India collided with Asia these sedimentary rocks were thrust upwards as the Himalayas were formed - and they are still growing! That is why today we can find these rocks hundreds of miles from today’s seas and thousands of metres up at the top of the highest mountains.
This same type of process occurred in the United States, but much longer ago, lifting rocks such as limestone high above sea level. This is why you can find limestone at the top of a mountain in Wyoming.
If you want to know more about this very exciting subject, see if you can find books on ‘Plate Tectonics ‘ and ‘Continental Drift’ in your local library. Also, any modern geological text book will cover this subject. Good hunting.
Question: In which ways do wetlands play an important role for birds? What is done to preserve wetlands for birds in general?
Answer: Wetlands, which include areas such as marshes, fens, lowland wet grasslands, broads and estuaries, are extremely important for birds. These areas are usually nutrient rich, highly productive areas supporting large populations of many different species of plants and animals upon which birds may feed. The diversity of plant species, from low-growing grasses to trees, help to provide a wide variety of habitats making them important and relatively safe nesting and roosting sites for many birds.
Wetlands are under constant threat from man’s activities such as farming and other forms of industry. It is important for the birds, as well as for other types of wildlife, that these areas are protected as much as possible from further development. Farmers, other potential developers, governments and the public are being made more aware of the importance of wetlands to wildlife. Organisations such as environmental groups are becoming increasingly involved in debates arising from threats to wetlands.
It is also important that most of these sites are managed in order to stop, or at least slow down, their gradual, natural succession into dryer areas. Labour intensive activities such as the building and maintenance of sluices, ditches and dams, tree control, reed planting, earth moving and the control of grazing must occur if water levels are to be maintained in many wetland areas. Public access to such sites must also be controlled for example through the building of paths.