Archive for January, 2012

If you were to ask people to name a famous scientist you are likely to hear answers such as Newton or Einstein.  If you were to ask me I would reply Mendeleev.  So why I do I think Mendeleev should be as famous as those other two guys? What did he do that was so important, I hear you cry? Well I will tell you, Mendeleev devised the Periodic Table, the most incredible document in the world of chemistry!

Mendeleev was a chemistry genius, not only did he manage to arrange the 80 or so  known elements of his time into the first ever Periodic Table, he left gaps in his table for elements he knew were yet to be discovered. Even more impressive, he correctly predicted the properties of the still to be discovered elements. If that was not brilliant enough, this was all happening in the days before we knew about atomic structure yet Mendeleev still managed to arrange the elements in order of their atomic number before atomic number even existed…that’s just totally WICKED, some would say INCREDIBLE.

If you look at the Periodic Table below it does not look very much like our modern day version but there are loads of similarities if you know where to look. The pink coloured elements are ones discovered after the death of Mendeleev but he had left the pink gaps to be filled in later. He was a very clever man.

Mendeleev's Early Periodic Table

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65 million years ago, the Earth suffered an extinction event which removed around 50% of all living species on the Earth, including all non-aviandinosaurs (more on that little detail later). The K-T extinction (or recently renamed the Cretaceous-Paleogene extinction) occured over a geologically short time span (between 100,ooo and 2,000,000 years) but left almost no major animal group without some casualties. The non-avian dinosaurs are the most famous, but a whole range of other important groups went extinct.

Allosaurus - a large carnivorous dinosaur

So, what didn’t make it through the event?

Non-avian Dinosaurs – Having been the dominant group of organisms on land for the past 135 million years, the dinosaurs were a very diverse and highly evolved group. Present on every continent, they occupied very complex food webs and ecologies. They were almost certainly warm-blooded (endothermic – generate their own body heat via respiration) and this would have made them reliant on a good and steady food supply. Dinosaurs had already been in decline for approximately 10 millions years before the K-T event, but what was the last straw?

Pterosaurs– Often thought of as dinosaurs or early birds, pterosaurs were in fact a group of winged reptiles that had their heyday in the Jurassic period, but were still present right up until the end.

Pteranodon - a large pterosaur

Marine reptiles– large marine reptiles such as plesiosaurs, mosasaurs and icthyosaurs didn’t make it through.

Mosasaur - large marine reptiles that went extinct at the K-T event

Ammonites – these large marine molluscs, easily found as fossils across Britain, had been very common right up until the K-T event, and then the entire group went extinct. Their closest cousins, nautiloids, survived however.

Which groups got through?

Avian Dinosaurs – Avian dinosaurs, or birds as they’re usually called, survived the event relatively intact. There were some species that didn’t make it, but the vast majority did.

Crocodiles – a distant relative of dinosaurs, crocodiles and alligators survived the mass extinction event, probably because their feeding habits and ability to burrow a little helped them through tough times.

Mammals– Luckily for us mammals made it through. At the time mammals had yet to diversify, and would have resembled rat-sized and rat-shaped animals. Whilst some groups took a hit (for example, marsupials), on the whole the group survived well.

Morganucodon - an early mammal

Fish – the vast majority of fish survived the K-T extinction, although sharks did a little worse than bony fish.

Amphibians – Frogs, newts and salamanders seem to have gotten through relatively unscathed, although their rather incomplete fossil record makes it difficult to draw strong conclusions.

There were other groups of course, but I’ve just focused on the main ones. So, what exactly happened to cause the loss of so many species, in such a short space of time? And why did some groups go extinct whilst others were able to cling on? Palaeontologists and geologists have found evidence of three major environment changes that occur around the K-T event. How could they have caused an extinction?

The Chicxulub Impact

65 million years ago, the Earth was struck by an asteroid, hitting the ocean in what is now part of Mexico. The asteroid was approximately 15km wide and released the 420 ZJ of energy (that’s the same as 1 billion atomic bombs).

Chicxulub - map of impact

This would have caused mega-tsunamis, massive wildfires across the Americas and the complete destruction of any large living things within 2000km of the impact. The most significant event however was the large amount of sulfur dioxide and other debris flung up into the atmosphere. This would have blocked the sunlight completely for about a year, and then reduced the amount of sunlight arriving by 20% for 10 years.

Artwork of the Chicxulub asteroid impact

This would have had a huge and very detrimental effect on any plants trying to photosynthesis, and would have severly disrupted any food chains. Evidence such as the crater, global layers of iridium (a metal rarely found on Earth) and deposits from mega-tsunamis show this event definitely happened, and currently most palaeontologists think that it is the main contributor to the extinction.

Chicxulub - Gravity anomaly map showing crater, now buried under sediment

The Deccan Traps

The Deccan Traps are flood basalts (a rock formed from volcanic eruptions) from before the after the K-T event near Decca, India.

Deccan Traps - map showing location

Produced by over 800,000 years of eruptions, these rocks show that there was massive volcanic activity at the time and this would have contributed to any gradual decline, as well as hindering any recovery. Producing large amounts of ash would reduce sunlight, and therefore photosynthesis, and there is evidence that chemicals released during the eruptions (e.g. selenium) may have interfered with the production of eggs in dinosaurs). However, recent evidence has suggested that whilst the Deccan volcanism would have cause signficant problems, it wasn’t enough to cause the extinction.

Deccan Traps - kilometers of basalt from the massive eruptions

Marine Regression

Towards the end of the Cretaceous, sea levels dropped considerably and this mean that large stretches of coastline were lost, along with the species that lived there. This would have severely stressed marine ecosystems, as well as organisms that lived near the coast (including dinosaurs).

So, what happened to the dinosaurs then?

The likely scenario is that sea-level changes and massive volcanism was causing environmental stresses globally. Reduced photosynthesis and loss of habitats meant that food chains became stressed and more vulnerable. Large demanding animals, such as non-avian dinosaurs, felt the effects first and struggled to find enough food. The same went for large organisms in the oceans. If you were small, or could scavenge and get by on detritus (dead organic matter) you had a better chance. Then, when the asteroid hit at Chicxulub it was enough to add that last bit of environmental stress, and pushed many already-vulnerable groups over the edge and into extinction.

So the dinosaurs are well and truly extinct then?

Well, actually, no. You’ll notice that I’ve referred to dinosaurs as ‘non-avian’ dinosaurs, and to birds as ‘avian’ dinosaurs. Birds actually share a direct, unbroken lineage to small carnivorous dinosaurs. This is supported by excellent fossil evidence (of feathers, bone structure, sleeping posture and more) and also DNA evidence that shows that birds are dinosaurs. In fact, the classification that birds belongs to (Avialae) is actually part of the Dinosaur superorder. So, the next time you watch a crow walking across the lawn, imagine it without any feathers and you’ll see exactly how similar they are to their ancestors. So, to answer the question ‘What happened to the dinosaurs?’, the answer is they grew feathers, wings, and started chirping!

Falcarius utahensi - a feathered dinosaur

Dr Frederick Banting - pioneer of insulin treatment

This week marks the 90th anniversary of the discovery and isolation of insulin by Dr Frederick Banting, a discovery that has saved and improved the lives of millions of diabetics.

What is Diabetes?

Diabetes is a serious disease that affects over 250 million people globally, in which the body either doesn’t produce enough insulin (Type 1) or doesn’t respond to the insulin that is produced (Type 2). This leads to a high blood sugar level, and this causes a variety of medical problems if not managed. 90% of cases are Type 2 diabetes.

 
What is insulin?

Insulin is a hormone produced by the pancreas. It plays a central role in controlling and regulating the amount of glucose in the blood. It does this by causing cells in the liver (and some other cell types) to store the glucose as glycogen. Insulin is injected by Type 1 diabetics as part of their treatment. Type 2 diabetics may sometimes need to inject insulin, but their treatment and management focuses mainly on lifestyle and diet control.

How was insulin discovered?

Before insulin was discovered, diabetes caused death in nearly all cases. The only treatment available was a strict controlled diet and this only gave the patient a few more years. In the 19th century a German medical student called Paul Langerhans had identified a set of cells in the pancreas that didn’t seem to have a function. (These were later identified as beta-cells which produce insulin). A few years later two other German scientists showed that the pancreas was involved in controlling blood-sugar, because they found that dogs that had their pancreas removed developed diabetes.

Location of the pancreas

In 1920 Dr. Frederick Banting, a Canadian surgeon in Toronto, developed a process for isolating a secretion from the pancreas that was shown to prevent diabetes when injected into dogs that had had their pancreas removed. With this isolated secretion now named ‘insulin’, Dr Banting and his team started testing on human subjects, beginning with themselves. They managed to develop the correct dosage and in January 1922 gave insulin to a 14 year old diabetic boy, Leonard Thompson. The insulin worked perfectly, and Leonard recoverd from near-death. In 1923 Banting was awarded a joint Nobel Prize for Physiology or Medicine and a medical company went on to mass produce insulin.

Leonard Thompson - the first person to receive insulin.

Whilst insulin doesn’t cure diabetes, it means diabetics are able to regulate their blood glucose levels and stay alive. Perhaps you’ll agree that the discovery of this treatment is one of the great medical advances of the 20th century.

Nature at Loreto

Posted: January 16, 2012 by tvineloreto in Animals, Biology
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As you stroll from building to building or sit out on the front lawn on a warm sunny day have you ever taken the time to stop and look around at the school grounds. We are blessed with beautiful grounds which are a haven for wildlife. The well established trees, lawns, flowerbeds and new pond provide a wide range of habitats and hidden within is an amazing array of animals, you just need to know where to look.

You cannot have failed to notice the bin-diving squirrels or heard the noisy cackling of the magpies but what else is there to see if you just take the time to look and listen?  We have a large variety of birds visiting or living in our grounds and during the week of 23rd Jan – 28th Jan, students at Loreto will be taking part in the Big Schools Birdwatch organised by the RSPB, an annual event used to collect wildlife data on a national scale.

If you would like to find out more about the RSPB’s Garden Birdwatch 2012 or take part in your own survey clink on the link       www.rspb.org.uk

Here are just a few of the birds you might see around Loreto College

The Robin

Robin (Erithacus rubecula)

The Robin ( Erithacus rubecula)

Probably the best known British bird, both the male and female have the distinctive red face and breast, white underside and brown plumage. Juveniles are brown. Robins are highly territorial and signal their presence with a beautiful, melodic song.

 They are a gardeners companion, following a gardener to snatch up any worms or insects disturbed whilst they work.  Often spotted in the flowerbeds by the main school entrance

 
 
 

Blackbird

Blackbird (Turdus merula)

A very common sight in parks and gardens. Males are glossy black with a yellow beak and yellow eye-rings,females are brown. They have a rich and beautiful song and sing from high points such as rooftops  and aerials.    A common sight on the school front lawn and by the Mary Ward Block.

 
 
 

Dunnock

Dunnock (Prunella modularis)

 Small, with brown plumage but has a greyish hue on the sides of the head and on the breast.

Often mistaken for a sparrow as it is similar in size and colour but Dunnocks have a much slender beak. Seen  in the flowerbeds by the main entrance and in the fenced off area by the pond.

 

Blue Tit

Blue Tit (Cyanistes caeruleus)

 Small, colourful garden bird and a regular visitor to bird tables. It has a distinctive ultramarine cap, wings and tail and a yellow breast. Face is mainly white with a horizontal black line through the eye. Breast is yellow with a small black vertical stripe

 Another gardeners favourite due to its love of small insects and caterpillars. Its acrobatic antics on bird feeders and fat balls make it an entertaining bird to sit and watch.

 Seen throughout the school grounds especially the magnolia trees in front of the school office.

Great

 
Great Tit (Parus major)

 Not to be confused with a blue tit, it is slightly larger and has a black cap which extends down the side of its head as far as the eye socket. It has white cheeks and a yellow breast with a large black central stripe.

 Seen throughout the school grounds.

Mallard

Mallard (Anas platyrhynchos)

 Male has an emerald-green head and blue and white band on wing. Female is predominantly brown but with the same blue and white plumage on the wing.

A spring time visitor to Loreto often seen strolling across the front lawn or taking a nap in the middle of it.

Song Thrush

Song Thrush (Turdus philomelos)

Named after its wonderful song. A medium-sized garden bird with brown plumage and a very characteristic pale breast with v-shaped dark spots on.  Another gardeners friend due to its love of snails. It is common for a thrush to have a preferred “anvil” , a large stone used to smash open the snail shells.

 Seen on the main lawn and in the shrubs along the main school wall.

There are many more species of birds living in our grounds, why not see what you can spot?

Stargazing Evening

Posted: January 12, 2012 by Mr Bilton in Field Work, Physics, Space
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 Jupiter and Jupiter’s Moon Io by Robert Altenburg (left)

After postponing the 2012 Winter Loreto stargazing evening on Wednesday, we crossed our fingers for the weather to help us having a look at the Universe tonight.

Unfortunately the clouds appeared while the telescopes were being assembled – but they were not enough to stop us from zooming in at the night sky.

Those who joined the Science Department last night were able to see what Galileo Galilee saw when he first pointed his telescope at Jupiter, the “king” of the planets, along with its 4  moons, Io, Europa, Ganymede, and Callisto .

Despite the cold, the brave Loreto girls and parents also learnt how to find Polaris (the North star), Betelgeuse and the Seven sisters.

The Loreto College stargazing evening was a success, and we hope we can count on more of you to come along next time.

Thanks to all those who came.

A big THANK YOU  to Setpoint Herts, Ms Ellis, Ms Hyslopp and Miss Vine for letting us borrow their binoculars and telescopes. Without them this would not have been possible.

Imagine you had a time machine. You park it out on the main lawn and then programme it to go backwards in time. Unfortunately you doze off, and when you wake up 112,000,000 (112 million) years have gone by (that’s 40,880,000,000 days). What would the world look like? Luckily, there’s a way to find out. The rocks beneath the school record millions of years of history, recording evidence of the environments and organisms that have occupied the very spot that our school now fills.

So, what exactly would you find?

The drawing below shows an approximation of the geology beneath the school (the ages are approximate and it’s not to scale).

Approximate stratigraphy beneath the school

The lowest rocks shown in this cross section (and there are deeper, older ones, not shown) are called the Gault Clay. They were formed about 112 million years ago. That was during the Cretaceous period. On the land dinosaurs were going about their business, but at that time most of southern Britain was underwater, covered by a sub-tropical sea.

Postion of continents in the Cretaceous - Britain is shown by the dot

The water was relatively calm, which is why fine sediments like clay could be deposited. In some places, the current was a little stronger and sandy deposits were formed (these became the Upper Greensand).

Marine life in the Cretaceous

If you sat in your time machine, deep beneath the waves, you would have seen a rather impressive array of now-extinct animals – molluscs like ammonites and belemnites, and large carnivorous marine reptiles like ichthyosaurs and plesiosaurs.

A sub-tropical sea - how southern England looked in the Cretaceous period

You set your time machine to tick forwards, slowly, watching things change around you. Around 99 million years ago the seas become deeper and now no material reaches the sea floor from the distant coastline.
Instead, the skeletal remains of algae form a steady ‘rain’ of particles, slowly settling onto the sea floor. These tiny plates of calcium carbonates are produced by algae near the surface, and are called coccoliths.

Coccoliths - tiny plates produced by planktonic algae

Their remains will eventually form chalk, and in Hertfordshire the chalk is approximately 220m thick. Considering that each coccolith plate is 0.0025 mm in size, that’s an awful lot of algae needed to produce a huge amount of chalk (incidentally, the chalk that forms the White Cliffs of Dover is of the same age).
At the end of the Cretaceous movements of tectonic plates formed the Alps in Europe, and the rocks in the entire region were folded, tilted and changed. Southern Britain didn’t escape unaffected, and the sea floor was shoved up until it became land. Then, erosion and weathering worked on the surface, removing some of the rock that had formed on the sea floor.
This continued for millions of years, with little material being deposited except by occasional rivers and floods. However, 400,000 years ago Britain (and the rest of the Northern Hemisphere) was in the clutches of a major ice age (called the Anglian Glaciation).

The extent of the ice sheet during the Anglian Glaciation, 400,000 years ago

At this time an ice sheet covered most of Britain, and eventually, as the ice melted and retreated, dumping sediment, meltwater streams left huge amounts of material over the landscape.
These form the most recent deposits beneath our school. Slowly, a layer of soil built up over these sediments, and then in 1922 our school was built, on top of all that history!
So the next time you’re sitting on the front lawn, spare a thought for what’s beneath you, and where St Albans has been over the last 112 million years.
Want to read more? Information on the Geology of Hertfordshire

Dancing Fire!

Posted: January 7, 2012 by Mr Pimentao in Physics, Uncategorized
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Sound seems to have caught the eye here at Loreto’s science cyberspace presence.

Whilst “youtubing” aimlessly like a headless chicken, I came across several videos showing a Ruben tube.

This is a perforated tube connected to a supply of flammable gas on one end, and attached to a speaker on the other end. As the gas flows through the tube holes, the (standing) sound wave created inside the tube by the speaker causes areas of high and low gas pressure. If you fire the gas up, it becomes an impressive flame show. The height of the flame is taller in the areas of higher pressure, so it acts as a visual display of the sound wave that travels inside the tube.

Some people like to play a single note on the speaker and are happy with that. Others experiment with all kinds of sound : from dubstep to glam rock!

Videos:

Mythbusters playing with Rubens tube

Another one bites the dust on Rubens tube

Bad romance on Rubens tube

The most endangered cat – from Iberia

Posted: January 5, 2012 by Mr Pimentao in Animals, Biology
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Just over 100 animals make up the remaining population of the Iberian Lynx

The loss of their habitat to farming and tourism development in southern Portugal and Spain, added to shortages in rabbit availability due to myxomatosis have brought this species close to extinction.

For 30 years, conservation efforts have managed to save the species from extinction, but it has been very hard to maintain stable breeding populations. Today it is estimated that there are only 38 breeding females in the wild.

Links:

Saving the Endangered Iberian Lynx in Europe – video from National geographic

Iberian lynx (Lynx pardinus) video

WWF

The Sun Project

Posted: January 4, 2012 by Mr Pimentao in Engineering, Physics, Space
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We sometimes take things for granted. Things like the food on our plate, the air we breathe, the water running from our taps. All of these would not be there if it wasn’t for our star, the Sun.
The Sun Project is an Astronomy and Engineering club.

The pupils involved have been developing solar panels to heat up water, investigating solar cells and how they can be used to build toys, or observing the surface of the Sun. Everyone is welcome to join at any time.

 

Solar storm, October 2003

Non Newtonian fluids

Posted: January 4, 2012 by Mr Pimentao in Physics
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Many people have heard of Sir Isaac Newton. He is famous for developing many scientific theories in mathematics and physics. Newton described how ‘normal’ liquids or fluids behave, and he observed that they have a constant viscosity (flow). This means that their flow behaviour or viscosity only changes with changes in temperature or pressure. For example, water freezes and turns into a solid at 0˚C and turns into a gas at 100˚C. Within this temperature range, water behaves like a ‘normal’ liquid with constant viscosity.

Typically, liquids take on the shape of the container they are poured into. We call these ‘normal liquids’ Newtonian fluids. But some fluids don’t follow this rule. We call these ‘strange liquids’ non-Newtonian fluids.

The viscosity ( how “runny” a fluid is) of a non-Newtonian fluid depends on things such as the stress, or pressure applied to them. This means that a quick change in the pressure applied to such a fluid might change its viscosity.

Cornflour solution on a speaker cone.

This is the reason that explains the formation of these cornflour “creatures” . Corn starch is a shear thickening non-Newtonian fluid meaning that it becomes more viscous when it is disturbed. The changes in pressure created by the sound vibrations change the viscosity of the fluid, and the result is fantastic. Check it out here.

Another classic example is Mr. Tickle walking on custard.