Category Archives: Science

GCSE Chemistry Lithium cells in the Economist

In this week’s Economist magazine, a description of Lithium and Sodium ion batteries could easily have come straight from the GCSE Chemistry syllabus, particularly the atomic structure section.

The article describes the fact that with both metals being in Group 1 of the Periodic Table, they have a single electron in the outer shell, which is easily lost to form the positive ion. And this electron, rather than let us say being transferred to a chlorine atom to form sodium chloride, instead forms the electric current generated by the cell, which has a good “energy density”.

The context is that part of the push for transition from fossil fuels involves moving to electric vehicles (EV’s) which generally have a lithium ion battery. These typically use nickel and cobalt lithium oxides as the cathode, and lithium carbon (graphite) as the anode. (The reason that Lithium alone is not used is that as we know from our GCSE, Lithium is very reactive, too reactive in fact)

The problem with this design is that Lithium is scarce and like the Nickel and Cobalt requires mining which itself can damage the environment.

So the Economist argues that sodium ion cells, in alliance this time with iron and manganese,  involve metals which in all cases are much more easily and abundantly available. But the magazine highlights the problem, again using the Chemistry syllabus, that because sodium is one further down in Group 1, it has more protons and hence is heavier and so may not be used in EV’s (already creaking under the weight of Lithium batteries) – but sodium ion batteries can however be used in heavy duty applications like power grid storage or even at home, when weight does not matter so much.

All of which goes to show just how important is the GCSE Chemistry syllabus!

Coronavirus, school and tutoring

Possible developments and updates

November 14th. It is now time to end this particular blog or else it will go on forever!. Schools did indeed return in September and in my view teachers and their representatives, and pupils and parents have all done a great job in keeping the show on the road, at the time of writing, in difficult circumstances At this stage exams in England are going ahead, delayed a little to June or July, but it seems inevitable some changes such as reduced syllabus or exam questions options will be introduced. What is clear is that one aspect of education has changed forever, namely the use of on-line technology, which surely will be a permanent part of the mix even when things return to normal.

August 17th. At this stage its is likely that schools will return in September but still not certain, with Case numbers creeping up. But the real story is A- Level results and the move to stick with Teacher grades. Comparing these to previous year actual outcomes versus predictions indicates significant grade inflation will therefore take place. The infamous algorithm actually did its’ job in bringing the broad sweep of grades back to where they should be. However: two problems. First, when applying correction factors, the algorithm produced some ridiculous individual results such as fails when no exam was taken. And second, it seemed to favour smaller class sizes, which are more common in private than state schools.

July 7th Various announcements have been made that schools will indeed go back full time in September for all Years which is good news. The emphasis will be on hygiene, from washing hands to cleaning surfaces, and minimising contact through staggered timetables, one way systems etc. Rather than a strict 2m rule throughout school, though avoiding 1m still seems required. This will be difficult, but the alternative of further virtual schooling may be worse. I think it will happen, but with nuances like cutting back on aspects of the syllabus content, shorter exams and perhaps still some virtual learning (after all, some of it has been very fruitful)

One aspect of the lockdown not much talked about is the loss for Year 11 and 13 of the “going into school to get results” day, and the leaving events like Proms, and so many end-of-school holiday trips have been cancelled. It is so sad for that generation.

June 19 Primary Schools have been back since June 1, years 1 and 6 at least. Years 10 and 12 have just begun to return, a few 2-hour lessons per week on face to face, mostly focussing on core subjects. Its is a slow start but we’re getting there. Some schools are really pushing on-line work rigorously, others less so. One school I am in touch with are setting exams at end of June for Year 10’s, not far off mock GCSE standard that’s good. I can see that the on-line novelty will wear off and we need to find a way of getting children back to school, safely of course but with an attitude of “we’re gonna do this”. If not for this school year then certainly in September. I think year 10 parents are the most worried the GCSE’s will be affected and why demand for Year 10 tuition remains very high.

For year 11’s (the forgotten year) two things are happening. First, yes we know their predicted grades will be formulated into actual grades in August. Some surveys have suggested they will be half a grade higher than last year. Perhaps the final examiners will bring them back down a touch but it seems reasonable. The issue for me is that children need four go’s at really learning a topic but Year 11’s missed out on the final pre exam revision push.

So that means that the if they take a topic forward to A Level they will have missed out on that final embedding of knowledge which forms the beginning of AS Level. Which is why – the second happening – it is a great thing that schools are beginning to use the June/July hiatus for Year 11’s to begin year 12 AS Level, even if its is with videos and on-line learning. (And why I am running Maths for A Level science courses for Year 11’s! )

Today we had the publication of plans for NTP the National Tutoring Programme and it certainly seems to have had a lot of thought put into it. The website is up and running and the aims and resources are clear. I think we should wish them well in trying to do the catch up of lost time, and maybe even at the other end of the programme providing a permanent means for disadvantaged pupils to keep up.

My tuition for International students continues about the same level but there’s just a hint that some are hesitating as to whether the British international schools will be open in September. We shall see.

May 11 The beginning of the end. Or the end of the beginning. The Prime Minister announced that some restrictions will be eased and said he hoped first and last year of primary schools could open from June, with secondary perhaps seeing some face to face teaching July. But I think it will take a lot to persuade parents and teachers alike to believe it is safe. I believe it is 50:50 whether any schools reopen before September – or at least more than they are now because we shouldn’t forget technically they are open to a small number of vulnerable pupils and those of front line workers.

May 8. Still full. I lost my first Chinese pupil whose parents understandably were hesitant to continue lessons in the uncertainty about resumption. But the place was quickly filled by an extra UK lesson. Zoom works well on Waiting Room but slightly annoyingly when 1 person is Waiting and 2 are in the lesson that counts as 3, which means maximum 40 minutes so you sometimes have to restart. I have found a way of helping with student’s school web tasks but feeding the questions back into a mix of past paper questions to check they can do them without help. I’m also extending Maths for A-Level Biology to Maths for A-Level Chemistry.

Still no sign of at-school restart : safety has to be guaranteed, so if not straight after half term, that would mean end of June earliest – and what would be the point for a few weeks. Are we into Alice Cooper territory? Schools Out for Summer. Schools Out Forever? The lyrics are eerily appropriate.

April 24 The first full week after Easter and it looks like all the pupils in my schedule have returned for on-line lessons. I have adjusted Zoom to include a password and the excellent waiting room feature. For GCSE students the Maths for A Level Biology programme seems to be working well; while continuing GCSE work is useful just in case resits are needed and to keep a learning focus, I’ve offered a programme which looks forward rather than back.

Still no sign of the plans for restart: these could vary for a phased resumption before half term on geographic and yeargroup basis, to a more widespread resumption immediately after half term, to a wait till September. My instinct is for the middle option, but we shall see. Years 10 and 12 will probably be a priority.

April 3 The second week complete and all my pupils have now used Zoom with me successfully , albeit I’ll adjust some settings during Easter. Some schools now looking forward rather than back, beginning A-Level introduction early for GCSE students rather than continuing GCSE work for which there’s no exam and its now become clear today that current work will not count towards GCSE because “schools have also been told not to set extra work to inform the predictions, because young people may not be able to do themselves justice if they are incapacitated by illness or have a difficult home environment”. Likewise with some of my GCSE students I will begin “Maths for A-Level Biology” early.

March 28 The first week of shutdown has completed and Zoom is working pretty well for my remote tuition. There is a boom in Zoom round the world it seems. Schools have been using Microsoft Teams, Google Classroom, Show My Homework, Hegarty Maths, Kerboodle among others to set on-line homework tasks which vary from watching videos to answering questions and entering answers. It looks like Year 13 A-Level students’ tasks do indeed still count towards final grade; with Year 11 GCSE it is a little less clear how important their continued diligence is.

March 20: schools have shut down. Some clarity received from Government that cancelled exams will NOT mean that GCSE s and A Levels are not awarded: rather that the criteria for allocating grades will be determined by predicted grades, mocks, and coursework which teachers will collate and inform examining boards of their recommendation. These grades will be awarded earlier than usual in July and so appeals may be received and possibly an optional Autumn term exam will be arranged. What is not quite clear is whether tasks submitted on line over the next few weeks will count towards grades. Until informed otherwise we have to assume they will.

For year 10’s who are not yet taking exams the objective must be to take on- line tasks, teaching and tuition seriously and diligently to ensure the prolonged absence does not adversely affect their chances at GCSE next year

Today’s various announcements marked a Rubicon so from now I will be doing on-line tuition only till further notice, which some of my UK pupils have already started with me using Zoom. My Chinese students already do this and it works well.

March 19 : update: schools beginning to shut down and set up homework and revision material on the web systems. Some are timetabling the issue of new material to when their normal lesson times would be and some are planning to run live webinar lectures at lesson times. I am beginning to do on line tuition to UK students in the afternoon (already plenty of Chinese in the morning) and finding so far Zoom better than more well known Skype.

Still no word on decision of what might replace exams as a qualification.

March 18: update: announcement that all schools will close Friday and that exams will not take place in May/June. An announcement will be needed as to whether this means postponement till September, or waive through on Precited Grades. PM’s phrase “pupils will get qualifications” could indicate the latter. I am beginning to see how schools will keep their pupils busy: good on line portals like GCSE Pod or Show My Homework are places to set tasks.

A thought: one of the world’s most valuable Apps in moral terms is “Nextdoor” where you can find out what is happening locally, and who knows what its now worth in financial terms. Other Apps whose time has come include Zoom and Skype.

March 17 : update: Teddington has moved to closing most of the school but keeping Year 11/13 open. The reason is associated with shortage of staff, self isolating or on sickness.

Similarly Waldegrave is closing except for Year 7, 11 and 13 which remain open and Orleans Park is open for years 7,9,11,12 and 13 only.

This leaves keeps things moving for GCSE and A Level and leaves open the possibility of completing those exams but of course things are fast moving and may change.

Parents from year 10 are beginning to ask about possible extra tuition.

March 16

My personal opinion is that after this weekend the chances of UK schools having to close due to Coronavirus have moved from below 50% to over 50%. Whatever the science says, peer pressure may become irresistible. If closure happens, the length could be perhaps 4 weeks, 2 of which luckily are at Easter holiday; all the way up to 6 months including summer holidays.

With a short stop, perhaps pupils in Year 11/13 who would be most affected could receive remote schooling, reassemble for exams, and examiners might lower the grade boundaries. But for an extended outage, the question would then be, what about qualifications for 6th form and University, assuming that no exams would be possible in May unless on-line exams were mobilised quickly?  I don’t believe that everyone repeating their year would be an option; firstly I do not believe pupils would want that, and second the capacity is not available unless you roll all the way back to nursery and delay the very first year of schooling.

Even a half way house of taking GCSE/A Level in September would be problematic as it would mean starting the next Year after Christmas, and requiring pupils to maintain “mental fitness” all over this summer. So an interesting alternative compromise is nearby Teddington’s plan to close the school except for Year 11/13, which at least keeps things moving.

If exams were to be cancelled altogether and yet pupils progress to the next level, that then implies that coursework and predicted grades at GCSE and A Level would come into play, as a means of determining 6th form and College admissions. But this is speculation. We shall see. Currently isolation for over 70’s seems to be the focus, but certainly schools are beginning to plan – for instance my school at Waldegrave is encouraging pupils to take more books and equipment home each day in case a sudden instruction comes.

As a tutor, whatever happens, I will offer options to parents of continuing as normal, or moving to on-line, or (and I hope not) stopping altogether. Note that better than Skype for on-line is a purpose built free programme called Zhumu, which I already use extensively with my morning Chinese students and remote Europeans and the tutoring works very well using this system. Needless to say we have already introduced handwashing.


The Biology of Coronavirus is interesting to say the least; at GCSE level we know that viruses, despite causing so much grief, are not actually living, as they do not have enough of the MRSGREN characteristics (more on that in future updates); they only live when a host is found, where they can rapidly replicate; and antibiotics do not work, instead a vaccine is needed to prevent infection rather than cure ; and at A Level you would know that the reason that soap and water is so effective is that the hydrophobic part of the soap can rupture the lipid membrane of the virus (see below)

On a lighter note

Regular readers will know that a pop song is never far away. Let’s hope the outcome is less of John Lennon’s “hold you in his armchair you can feel his disease” in Come Together, or Depeche Mode’s “you know how hard it is for me to shake the disease”; rather Paul McCartney’s “Its getting better all the time” (he always was more optimistic), a song which originated when Ringo fell ill in 1964, and was temporarily replaced with drummer Jimmy Nichol, who played five concerts before Ringo was well enough to return. During Nicol’s tenure John and Paul constantly asked him how he was coming along, to which he always replied, “It’s getting better,” In 1967 Paul made this into a song for Sergeant Pepper.

Medical advice might be, as the Police say, “Don’t Stand So Close to Me” (and that was actually at school) or remain as X-Ray Spex would say, a Germ Free Adolescent.

As events develop I will update this blog. Auto updates are possible if you complete the subscription form

2019: the year of the Periodic Table

Did you know 2019 is the Year of the Periodic Table and its 150th birthday? Me neither! It has to be one of the least publicised “Year Of’s”  and yet one of the most important.  Dmitri Mendeleev’s creation attracts me in two respects, first for the science and second for the use of the highly visual illustration to simply explain it. The Table has evolved in to the colourful all-in-one-page presentation of data with shapes or pictures that I like – think Infographic, think London Tube map.

The Periodic Table is wonderful in that it answers so many questions about physical science, and if all that you know about Chemistry is the Periodic Table and the answers to the questions below, then you are well on the way to a GCSE Chemistry pass. As an adult you are welcome to this understanding but please feel free to skip to the “fascinating facts” towards the end and find Mendeleev’s position in the history and philosophy of science.

What is an element?

An element is a substance that contains only one type of atom, such as hydrogen; in contrast to a compound which contains more than one type of atom, such as H2O. A molecule contains more than one atom – of the same type such as O2, or different types such as H2O).

Some elements have an obvious single letter and some don’t; why is that?

Hydrogen and oxygen simply are called H and O whereas Magnesium is Mg and Potassium even more strangely is K (from the Latin Kalium). So there are many reasons, for instance Beryllium, Boron and Bromine couldn’t all be B.

What’s the difference between a Group and a Period?

The Groups are the downward columns and the Periods run across. Groups generally have elements of similar properties like Group 1 metals and Group 7 Halogen gases. But the properties from left to right of a Period are completely different e.g. from metallic to gaseous. The common factors in Periods is the electronic shell, so the second Period 2 is the second electronic shell.

What’s the difference between the top number and the bottom number of an element?

The top number is the atomic mass (A.M.) while the lower one is atomic number (A.N.). The atomic mass is the number of protons and neutrons while the atomic number is just the number of protons (and also electrons). So sodium has 11 protons and 11 electrons (A.N. 11) and adding in the 12 neutrons makes A.M. 23. The modern Periodic Table is in the order of atomic number; Mendeleev ordered elements by atomic weight (became mass) which in the end is very similar.

What is the order of elements?

As you go across the table left to right, the atomic number increases by 1 each element, going from Hydrogen (A.N. 1)  to element 118, Oganesson  (Og),  formerly Ununoctium (UUO, A.N. 118). Atomic mass also increases, albeit sometimes by more than 1. Along with many elements towards the end of the table, UUO is unstable and in fact only 3 atoms of it have been produced since 2002. When Mendeleev first published his Table in 1869, he left some gaps, but made predictions of properties which in due course did fit new elements such as Group 3 Gallium.

Can we use the Periodic table to identify metals and non-metals?

Broadly the metals are on the left and in the centre while the non-metals are on the right.

The transition metals in the middle don’t seem to follow the group number pattern. Why?

At GCSE level we just mainly consider the first four periods and so for example period 2 group 1 e.g. Lithium and group 2 e.g, Beryllium  then skip over the transition metals to group 3 e.g Boron and on through groups 4,5,6,7 to the final column for Nobel gases.

Why is the final group called group 8 sometimes, but also group 0 ?

This gets to the heart of the electronic structure of periodic table. The common factor of the final columns is that all the elements have stable outer electronic shell configurations which at GCSE level generally means 8 electrons in the outer shell, and so zero in electrons in the next shell.

So what other parts of the periodic table relate to electronic structure?

Sodium’s electronic shell structure

The group number determines the number of electrons in the outer shell (and vice versa). So group 1 metals have 1 electron in the outer electronic shell, and for instance sodium is A.N. 11;  so its 11 electrons have configuration 2,8,1 Then group 2 elements have 2 electrons in the outer shell, and so on through group 4 with 4, and group 7 halogens with 7 in the outer shell.

Does group number determine the type of reactions elements have? 

Absolutely! Group 1 elements are keen to release their single outer shell electron to go back to a stable outer shell of 8 and so react strongly to, for instance, water and acids to form ionic compounds in which the metal ion has a charge of 1+. Meanwhile group 7 halogens are adept at gaining the one electron for a stable outer shell. So Na+ and Cl- from an ionic bonded compound whereas chlorine bonds covalently with hydrogen or itself by sharing rather than exchanging an electron.  Group 0 (or 8) Noble gases like argon are inert (they barely react) because they are already content with their full outer shell.

Can we predict which elements will form multiple bonds from the position in the Periodic Table?

Yes, oxygen in group 6 has 6 outer shell electrons and so needs 2 more and forms a double bond with itself or two bonds with hydrogen (which needs 1 electron) to form H2O (water). So the very familiar formula of water owes its existence to the position of hydrogen and oxygen in the Periodic Table. Nitrogen in Group 5 needs 3 more electrons so shares them with three hydrogen atoms to from the very familiar ammonia NH3. At the other end of the 2nd period, Beryllium in Group 2 cannot be bothered to gain 6 to make 8, rather it loses 2 to from the Be2+ ion, That is why group 2 metals like magnesium form 2+ ions.

Group 1 metals get more reactive as you go down the group whereas Group 7 halogens get less reactive. How does the periodic table explain this?

As you go down a group the atom gets bigger so the outer electron shell is further away from the positive nucleus. For metals such as potassium this means it is easier to prize away an electron from the claws of the nucleus than it is with the smaller lithium.  On the other hand the larger iodine is less willing to accept an additional electron than chlorine, because for iodine the positive nucleus is further way from the incoming electron.

Some elements like chlorine have a decimal place in the atomic mass whereas as carbon does not. Why? 

Isotopes is the answer. Chlorine has a 35 A.M. isotope and an 37 A.M. isotope in the ratio 75% : 25% and so the weighted average is 37.5. Carbon has several isotopes such as the carbon dating isotope C14 but they are in tiny proportions so the base isotope of C12 is used in the Table.

Why is Period 1 only 2 elements?

Hydrogen and Helium have respectively 1 and 2 electrons, after which the first shell is full and we move to the second shell which has the more familiar 8.  Hydrogen and Helium are the main constituents of the Sun and indeed the Universe, which begs the question, are there any elements in space not in the Periodic Table? You will find the answer in the final section, Strange Facts (about the Periodic Table)

So which Periods and Groups are important for GCSE?

For the first three periods i.e from elements H to Ar you should know each element in detail and arguably be able to recite and know their properties, reactions and electronic structure. Equally Groups 1 (alkali metals), 7 (Halogens) and 8 (0) Nobel Gases (and to a lesser extent Group 2 Metals) are important to understand in detail, and for these Groups extend your knowledge to Period 4 as well, for instance down to potassium and bromine.

For transition metals in the middle you don’t have to know their groups, periods or electronic configurations, but should be aware of their names and properties. For example copper, which conducts electricity and has highly coloured compounds like its sulphate,  and which features in core experiments. You do not need to know the details of radioactive elements but should understand the principles of radioactive decay.

Strange facts concerning the Periodic Table

Mendeleev’s elements – the Donald Rumsfeld of his day?
The Table has the look of a Patience card game. This is not a coincidence because Mendelev was a card player and initially sorted the elements by atomic mass, wrote them on cards, and placed them in columns of similar properties and increasing weight.

Eek! He initially missed out around a third of the elements because they had not been discovered but he was able to predict some of the missing element properties. When Mendeleev proposed his periodic table, he noted gaps in the table and predicted that then-unknown elements existed with properties appropriate to fill those gaps. He called them eka-boron, eka-aluminium, eka-silicon, and eka-manganese. Eka aluminium for instance correctly foretold the discovery later of Group 3 Gallium, with the atomic mass of 69 and density 6 times that of water – very close to what he had predicted.  Eka-silicon correctly became Germanium (atomic mass 72).

On the other hand he made no space for Group 8 Nobel gases – in a sense an omission but, being inert, they hadn’t fully been discovered yet because often elements were discovered by their reactions.   Another reason for omissions may have been that he was running out of time to publish, especially since other versions and lists were beginning to be circulated.

Iodine (127) has a lower atomic mass than tellurium (128). So iodine should be placed before tellurium in Mendeleev’s tables. However, since iodine has similar chemical properties to the halogens chlorine and bromine, Mendeleev swapped the positions of iodine and tellurium and made Iodine follow Tellurium, to be positioned in the right place below its halogen friends..  And in fact that’s how they appear in the modern table because of their atomic numbers (Te 52, followed by I53).  Mendeleev didn’t yet know about the significance of proton-based atomic number but in a sense he was predicting it. This is one of the very few examples where the order of atomic mass is not the same as atomic number.

The 92nd element is uranium but it can transform itself into other elements like lead through radioactive decay. Elements above A.N. 92 do not actually exist – not naturally anyway – they have to be artificially created and they also radioactively decay. .

Some scientists believe that although we have reached 118 now, we could go as high as 137 – but no higher because energy levels would not permit it.

The original classical elements as proposed by among others Aristotle were earth, fire, air and water, with aether the heavenly element soon added. The alchemists began to identify more conventional elements like sulphur and mercury, so that by Mendelev’s time the modern, full set was in reach.

So one might imagine Mendeleev as Donald Rumsfeld, who famously was mocked yet admired for his “known unknowns” description of military strategy.  Mendeleev’s “known unknowns”  were elements like gallium, germanium and scandium whose properties and existence he predicted before discovery. His “unknown knowns” were the iodine-tellurium pair which he placed in the wrong order because he was unaware of isotopes; and his “unknown unknowns” were arguably  Group 0 inert gases because, being inert, they formed no compounds; and the high atomic number elements including lanthanides, actinides and  radioactive elements.

Although in GCSE exams you are given the Periodic table, so it doesn’t need to be memorised, but just in case, you may wish to consult Google and the 120,000 ways of memorising it. Including songs like this one.

Each element has a story
There are only 2 liquid elements at room temperature – bromine, and mercury the “liquid metal”. Most of the rest are solid except for around 10 gases.

The lower elements are often named after famous people (yes, there is an Einsteinium, and a Curium) and also planets (Uranium, Plutonium, Neptunium). Note that Mercury the element and planet are both named after the god.

The country Argentina is named after the element Silver(Ag). Meanwhile Gold (after the Latin word Aurum) is so precious because it does not tarnish, being so unreactive, and it is a metal, again related to its position in the Periodic Table.

Carbon is the building block of life and forms many millions of organic compounds. Because of its position in Group 4 it requires 4 electrons for stability so typically forms 4 single bonds, or 2 singles and a double, with itself or other elements like Hydrogen in Methane (CH4, Natural Gas). Yet it is also the single element in strong and precious diamond.  It also forms graphite which has several layers of hexagonally arranged carbon – the graphite pencil works by a layer peeling away on to the page. Graphene is a new material – it is only one layer of graphite – so only one atom thick – yet is between 10 and 200 times as strong as steel (depending on the steel type)

A good reference for the details, pictures and uses of every element can be found in this link

Electronic structure and Heisenberg’s role in the War (possibly)
As you go across a Period, more protons and electrons are added, but the atomic radius, strangely, gets smaller. This is because the additional electrostatic attraction of more protons outweighs that of negative electrons. But when you jump to a new Period and new electronic shell comes into play. Hence as you go down Group 1 alkali metals the elements get bigger and more reactive since the outer shell electrons gets further way from the nucleus.

Mendeleev had no knowledge in 1869 of the astonishing advances in the early 1900’s of the knowledge of atomic structure, but he was on the right track with his view that the properties of elements depended on their atomic weight and hence position in the periodic table. One of these pioneers was  Neils Bohr – who developed the theory of electron shells and the quantum theory in the early 1900’s and which matches the Periodic table so well – was from a footballing family – a good player himself, his brother was a Danish international. Neils, of Jewish descent, also stood out against the Nazis, whereas Heisenberg (of Uncertainty fame) was more accommodating and the two had a mysterious and fractious meeting in 1941 concerning the development of the German atomic programme. Heisenberg showed a drawing, but there was disagreement over whether it was for a bomb or reactor. There is even uncertainty (of course!) about whether Heisenberg advanced Germany’s nuclear programme after the iconic meeting, or held it in check.

The book “Periodic Table” by author Primo Levi is a collection of short stories which links his love of science with his experiences in fascist Italy and in Auschwitz.

Space exploration, the Big Bang and the rest is history
We have not so far found elements in space that are not listed not in the Periodic Table. In fact all elements are thought to have been produced from Hydrogen and Helium after the Big Bang through various processes of fusion, fission, collisions, disintegrations involving for instance supernovas and neutron stars.  Many of the processes involving the protons, neutrons, and electrons of He and H began in the enormous temperatures in the first fraction of a second of the Universe, following which traces of Lithium and Beryllium, the next elements by A.N., emerged. Carbon soon followed (OK after a few million years!) and the rest is history (literally!)

Although the earth is principally solid, less than 1% of matter in the Solar System is solid. Exceptions include iron which is thought to be at the centre of all planets in our solar system.

And finally…the man himself

…more about Dmitri Ivanovich Mendeleev himself. A Russian scientist, from Siberia, one of 17 siblings. The world may have been a different place if his second fiancé had not agreed to marry him (he threatened suicide otherwise). She did marry him, a month before his divorce from his first wife (interesting timeline!). A Chemistry teacher who had just written the definitive textbook of the era, he claims to have envisaged the Periodic Table in a dream and upon awakening reproduced it.

He incorporated the periodicity of the properties of elements, and although he focused on atomic weight not number, his work seemed to hint at the future through his use of “valence” which would later evolve to reflect atomic number and electron shells.  The repeating patterns had been observed a few years before by scientists like Newlands and Meyer, but as is often the case timing is everything. So it was Mendeleev that is principally remembered; not just due to luck but also because his Paper, presented to the Russian Society of Chemists, included a coherent “pull it all together” theory which included predictions of new elements.

Mendelev was all set to receive the coveted Nobel prize in 1906 but at the very last the committee changed its mind -ostensibly because of the 37 year gap, but probably because of a trivial tiff (to which scientists are not immune!) The influential scientist Ahrrenius objected to a previous criticism of one of his theories!

One of Mendeleev’s originals (notice the gaps at 68 and 72)

Mendeleev  studied at St Petersberg, and helped to create the first Russian oil refinery. One of his  first tables is shown above from 1871,

Also below – what is now recognised as the oldest classroom chart version, dated 1885, found in St Andrews University; and in true Antiques Roadshow style, it was found in a dusty clear-out.

Credit : ST Andrews Periodic Table

There is a crater on the moon named after him, and, as you would expect, one of the elements, mendelevium, A.N. 101.

When Mendeleev died in 1907 his Periodic Table was well on the way to international acceptance but his last words were to his Physician. “Doctor, you have science, I have faith”.

For an amusing insight to the Periodic Table here is a Podcast by Professor Brian Cox


A banker GCSE science question – the environment; what students need to know.

There is much media talk and public interest about environmental issues like climate change, renewables, air quality, plastics and pollution. There are school children marches and protests for Climate Emergency round the world. Penalties for diesel cars to discourage nitrogen dioxide and particulate emissions are being introduced, and, astonishingly, the Tesla electric car company’s market value at £40 billion has now overtaken Ford’s despite only achieving a fraction of Ford’s sales. The UK Government is phasing out petrol engine cars by 2040 in favour of electric and voted for Zero net emissions by 2050. What can we say about the inclusion of these topics in Science GCSE? Well, firstly, there are lots of examples, and “environment” is one of the few certain, banker questions in the whole of the GCSE syllabus. The first new 9-1 GCSE science papers confirmed a very large number of “environment” questions for a relatively small part of the syllabus – hence very high value revision! Secondly, examiners are looking for proof that students understand some of the technical language involved. Let’s take a look in more detail.

Questions about the environment in general have become so popular in Chemistry, Biology and Physics papers, in both combined and triple science alike,  that I sometimes think you just have to mention “carbon dioxide” and you are half way to a pass ! Even if you are a climate change skeptic, suspend that view until after the GCSE’s! Certainly the payback on a relatively small amount of revision on a not-too-difficult subject is high since one or more questions will almost certainly feature – which cannot be said about all science topics. After a previous year’s “drunken rat” controversy, students tweeted that they had learned their CGP Biology guide religiously, yet so little of the syllabus cropped up.

A common fault amongst pupils is to confuse climate change and pollution, so that’s a good place to start.   Students should understand the following three key points:

1. All three of the sciences begin this topic with fossil fuels, which are mainly oil, coal and gas and derivatives like petrol and diesel.

2. There are two separate consequences of fuel combustion. On the one hand, the generation of the greenhouse gas carbon dioxide as a natural but increasing product of combustion. Then on the other hand emissions of bi products such as sulphur dioxide and soot  which cause pollution and smog.

3. And to counter these problems is the emergence of renewable energy sources such as solar power which reduce dependence on fossil fuel.

Candidates should ensure they understand both the advantages of fossil fuels and derivatives (fairly cheap, easily available, engines designed for them) and disadvantages (may run out, greenhouse gas generation, pollution, scars on the landscape). Similar pro and con assessments should be learned for individual, different renewables.
The basic mechanics of global warming should be understood. Rays from the sun entering the earth’s atmosphere bounce off the surface , and we need this to happen to a certain extent to provide warmth yet prevent overheating; but increased CO2 concentrations in the earth’s atmosphere don’t allow enough long wavelength infrared radiation to escape, leading to a small but significant warming of the earth. (This is the way greenhouse glass works). Pupils should also know that un-combusted methane itself is a greenhouse gas and that increased world-agriculture contributes to the climate problem (and yet provides food of course)

Some effects of global warming should be learned such as polar ice-caps melting; sea levels rising and coral reefs deteriorating as ocean temperatures rise; and species migration patterns changing.

Students should be able to interpret graphs such as global temperatures rising on the y-axis – but note the typically narrowed scale – with time on the x-axis, especially since the industrial revolution. These show global average temperatures rising around 1 degree C to 14.5 degrees, which alongside CO2 atmospheric concentrations rising from 0.028% to 0.040 % seem to provide a link.

Now let us summarise what revision is needed in each of the three sciences in addition to the above, and the type of question likely to be asked. (More detail is available in my coaching card lesson plans). Each science begins with the basic assertions above, particularly the part played by carbon dioxide in global warming, then develops different angles.


Pupils should understand how fractional distillation of crude oil works, including generating products such as petrol and diesel fuels as described in this BBC video about Grangemouth refinery where I visited many times in my work.

Students should learn the basic word equations associated with combustion of fuels which are generally alkane hydrocarbons .

Hydrocarbon +  oxygen –> carbon dioxide +  water + energy released

and one example, for natural gas combustion.

CH4     +            2O2             →         CO2          +        2H2O

And also the word equation for acid rain, which damages buildings and statues, especially limestone :

Sulphur Dioxide + Water -> Sulphuric Acid

Students should also know the formulae of Nitrogen Dioxides (NO and NO2) and also understand how incomplete combustion produces sooty carbon particles (turning bunsen burners yellow) and in extreme circumstances the poisonous carbon monoxide (CO). Methods of reducing emissions are important such as scrubbers at power stations and catalytic converters on cars.

(In a sense I am pleased to see nitrogen and sulphur oxides (called colloquially “NOX and SOX”) being given priority once more. As a performance analyst in BP in the 1990’s I collated the emissions data from BP Chemicals’ factories including NOX and SOX. When CO2 was suddenly elevated to a much higher importance, I always worried that focus on these polluters might be lost).

Although not in the syllabus as such, an interesting view of air quality real time results around the world, as judged by amounts of pollutants including NOX and SOX measured by detectors placed e.g. on buildings, is this web link  

The alternative fuels of particular interest in Chemistry are ethanol, bio-fuels like bio-diesel, and hydrogen along of course with their pros and cons.  A further branch to revise is the benefits of electric cars and the two main means of powering them namely re-chargable batteries and hydrogen fuels cells. At typical question would provide data for energy use, cost, mileage and ask you to “evaluate” the alternatives which means recommend the best with justification.

The cracking of alkanes to alkenes and subsequent polymerisation also features in this context both for the fossil fuel origin and the non biodegradable nature of plastics.

Another branch of pollution features in metals extraction and mining, with heavy metal dis-colouration of rivers a possible disadvantage as seen in this article about the Colorado river.

Exam Questions have ranged from simple (what type of reaction is burning fuel in oxygen?);  to numeric (compare the parts per million figures for particulates, carbon dioxide, nitrogen dioxide for several types of fuel); to everyday experience (why do supermarkets charge for plastic bags?);  to involved (describe how a fractional distillation column works).


For Physics pupils need to know more detail about individual energy sources both conventional and renewable. The energy transfer steps for several of these should be understood. So for power stations running on fossil fuels, the transfer is from chemical (in the fuel), to thermal (burning it), to kinetic (turbines and generators); to electrical (the grid).

Nuclear power involves a plentiful supply of uranium and plutonium but they are finite resources so counted as non-renewable. And of course though they have the advantage of being green in a sense – no carbon dioxide emissions – the disadvantages include waste disposal and impact of major break downs (albeit rare) like Chernobyl.

The major renewable sources to learn are: solar panels (see this video of solar powered city) and solar cells; wind turbines and wind farms; geothermal hot rocks; hydroelectric power; and tidal barriers. For each of these students should learn the energy transfer process, and advantages and disadvantages, perhaps two of each. For instance, for wind energy the transfer is from from kinetic wind energy to kinetic blade energy to electrical. The advantages include it’s renewable, and has zero carbon dioxide emissions and pollution; but it is not always available (when calm), the turbines can scar the landscape, and though costs are reducing they are expensive to build and maintain.

Typical questions have included: is global warming of 5 degrees C over the next 100 years a fact, a guess or a prediction?; why are copper pipes under a solar panel painted black?; calculate the cost of waste energy from a food processor and how it is manifested;  why do chemical salts used to store solar energy need a high specific heat capacity?; explain the difference in actual versus maximum electrical output percentages for a variety of energy sources; give 2 advantages and disadvantages of running gas fired versus nuclear power stations; why are transformers used between power stations and the national grid?; and what is the payback time on a project costing £1000 yielding savings of £500 per year (answer : a 2 year payback).

It follows that students should know and be able to apply formulae around energy efficiency, power and energy transfer.

Finally, although electric cars are not specifically on-syllabus, that won’t stop AQA or Edxcel throwing in a wildcard question like “compare the advantages and disadvantages of electric cars versus conventional petrol or diesel engine cars”.  Answers should include reference to easy availability of petrol (difficult for electric chargers); petrol is from fossil fuel and so contributes to global warning (electric cars do not – though the charger itself has to be charged); petrol and especially diesel cause particulate, sulphur and nitrogen dioxide pollution whereas electric cars do not; and conventional cars currently have a higher mileage range than electric.(Note that a £300m electric taxi factory is opening in Coventry – truth is stranger than fiction as 3 years ago an A Level Business Studies question case study was built around just such a possibility, Even Business Studies is not immune from our topic ! )


Photosynthesis and the carbon cycle are highly relevant in this context.  This is a must for Biology exams, not just for the environment  question. The word equation for photosynthesis must be learned:

Carbon dioxide + water (with sunlight) –> glucose + oxygen
6CO2                  + 6H2O    light –>            C6 H12 O6  +      6O2

(The reverse equation for respiration of course also is important)

The carbon cycle includes the absorption of carbon dioxide through photosynthesis in leaves, and the production of carbon dioxide through respiration and also decay of dead animals, which eat vegetation.  This has been in balance until recently when from the industrial revolution onwards fossil fuel combustion is producing more carbon dioxide – only by a fraction but enough to mean an increase in the concentration of carbon dioxide in the atmosphere, which in turn links through to the so-called greenhouse effect and global warming.

In Biology, further emphases include the generation of another greenhouse gas methane through more intensive farming, and the reduction in CO2 adsorption through Amazon rain forest depletion, in tandem with the production of CO2 from burning those forests.

Fossil fuel pollution includes damage to leaves from acid rain because their waxy layer for mineral absorption is damaged, while health is affected by carbon monoxide because in red blood cells it binds more strongly to haemoglobin than oxygen.

Further related topics include pollution caused by sewage and excess fertilisers, which can lead to eutrophication of lakes and oxygen depletion.

Typical questions include; describe the main points of the carbon cycle and the role of photosynthesis; what can we do to slow global warming?; interpret a bar chart of billions of tonnes of carbon dioxide produced at each stage of the carbon cycle.


Environment as a subject is as near to a banker question as you can get, and one of the few where parents can easily help children, especially as GCSE age is just young enough for pupils to still accept parental advice! Further, you will hear almost daily on the news stories about this topic,  whose science may well feature in GCSE and so a round table discussion could follow at dinner. The key points are to start with are fossil fuels, but distinguish between carbon dioxide emissions – said to cause global warming;  and sulphur and nitrogen oxides, bi product polluters causing building damage and health issues. Then candidates should be able to explain the science and list some solutions for these problems. The examiners want balanced arguments, so be prepared to list both the pros and cons for conventional and renewable energy sources.

Biology GCSE drunken rats question

Three of my tutorial contacts talked to me today independently about the GCSE Biology exam that is going viral. I Googled “#aqa biology” and sure enough a torrent of links and Tweets popped up.

It seems that AQA included  questions in Biology GCSE biology about drunken rats, why boys drink beer and girls drink wine, including under aged drinking references, and a Business Studies question about what is an independent company.

Almost simultaneously a number of Scottish students complained that their Maths exam did not reflect the syllabus, and crucially “a common complaint was that the exam bore little or no resemblance to past papers and exemplar papers”.

What is going on? Let’s examine the issues, which raise important questions in general about the direction of exams. AQA are a terrific exam board, but have they got this one wrong?

First, this is not the same as last year’s most-tweeted GCSE Maths problem about “sweets in a bag: show that n²-n-90=0.” .  That was difficult, but on-syllabus, albeit requiring two rarely connected parts of the syllabus, probability and algebra. Not the same either as the “Scottish crocodile” question which was valid but ambiguously worded.

This year’s problems perhaps reflect a disturbing trend among exam boards. To appear to be “relevant”, “on-message”, “out of the box”, “contextual with society”, to focus on the “ethics of science” and “how science is applied” – rather than test simple scientific fact.  Also, a surely mistaken desire to be “cool with the kids”.  There is a whiff of Millenium Dome here – let’s make science exams more interesting and the kids will abandon their computer games and flock to science!

While some of these aspirations may be desirable their inclusion in vital exams is clumsy, unannounced and too dominant.  If such questions are included, it reduces room in the Hour test for basic questions about biology fundamentals. The implication is that examiners see science more as a matter of opinion, not fact.

Examiners, perhaps inadvertenly give the impression that they do not appreciate that teachers and children work very hard to learn the syllabus, practice on past papers, and despair when they open the exam paper and see a whole series of questions bearing little overt relation to the syllabus. They take the syllabus very seriously – more so than the examiners perhaps. It is like training all year to climb Ben Nevis, you reach the top exhausted, remove a prearranged stone from a cairn to claim your reward, only to find a message saying “Ha Ha, fooled you, you’ve climbed the wrong mountain!”  A teacher estimated that “only 25% of the course content” was covered in the Biology exam.

To paraphrase Donald Rumsfeld, known unknowns we can cope with, it’s the unknown unknowns that are the problem.

The question about “what is an independent company” was no doubt aimed at the idea of fair, not biased testing, and perhaps “controlled” and “independent variables”, but surely a better question would be, “why is an independent company used”? (for drug testing)?

biology2Some challenging examination of science experimentation and data analysis is fine – I am a data scientist and welcome the inclusion of graphs to represent data, and questions about interpretation.  Healthy living and drug testing are indeed in the Unit 1 specification. But when questions are sexist, appear to condone breaking the law, or are from another subject altogether, things have gone too far surely.

How many boxes can you tick in one question? Sexism, under-age drinking, animal testing, drug-taking, newspaper accuracy! One is tempted to ask, what were the examiners on when they wrote the question?! But seriously, didn’t the management have a quick sense check, and quietly suggest, ”I think you should have another look at this one, it is inappropriate”. Important social issues, but in a Biology exam? Better on Nicky Campbell’s excellent “The Big Question” on Sunday morning TV?

This raises questions about quality control at AQA, which along with Pearson/Edexcel and OCR is truly a great and professional organisation. (An independent company in fact, non-profit making)  I had assumed the Q stood for quality (actually it is for “qualifications” and AQA should remember that’s why pupils take the exam). One hopes this is a temporary blip. Questions like these are actually reducing standards not improving them.  If the majority of syllabus topics are no longer included in the exam, what’s the incentive to learn them?

I am detecting another general trend across exams. In their desire to become more challenging (good!) examiners are including more and more words in their questions, but not following through to ensure that the English is correct and unambiguous (bad!). An experienced tutor told me recently that sometimes a pupil often “has to guess” what the examiner wants.

Another question in the Biology exam is about Malaria. OK so far, it is in the syllabus. But the question is shrouded in “extras” – for instance needing to know Maths GCSE standard form “power of 10” notation. A core of scientific experimentation is to change and test one independent variable at a time – but here the examiners themselves are simultaneously testing biology, and beyond-basic maths.

AQA have responded and are standing by their exam, saying they do not want it to be “predictable”. I have taught and trained many pupils and adults and what I have found is this: provided they are given clear instructions with no surprises they will pursue a difficult task to completion, otherwise many become confused and disheartened. The danger for AQA is that in their efforts to make science more “interesting” and “challenging” they will discourage interest, especially as these questions were in the basic science Unit 1 paper. They seem more appropriate for advanced students

The fact that AQA felt the need to explain the question on social media at all suggests it wasn’t very clear in the first place. The fact they defended it suggests we should expect more of the same, we should “expect the unexpected”.  This will mean more teaching time is dedicated to predicting and practicing for these flowery questions, and less time for the fundamentals of biology.  Examiners may be surprised, but optimising your grade really does matter.  Appliance of science is of course important, but not at the expense of simply knowing the fundamentals?

At the risk of sounding like a “grumpy old man”, and another thing: core Unit 1 science GCSE contains no questions about electrical circuits or electrical safety but generally contains questions in Biology, Chemistry and Physics about the evils of fossil fuels,  carbon dioxide and global warming. On-message indeed!

The other issue emerging is the annual use of Twitter and other social media by pupils to vent frustrations with exams. While I am not a great fan of “trial by social media” I think this method of scrutiny is here to stay and exam boards must expect more in the future.

In summary, my beef is this. Though “application of science” is directionally right, and AQA are a fine organisation, the quality control on questions needs to be stepped up.  We need less social posturing in science exams. The syllabus content may be reasonable, but the questions do not sufficiently or overtly reflect the syllabus.  And when they do, they are shrouded in unnecessary, periphery extras, obscuring the basic facts around the subject.

A GCSE Chemistry substance found on planet Mercury

News today from the NASA Mercury probe that an unexpected substance has been found on Mercury, in fact making up the outer crust of planet Mercury. The substance is graphite, which will be familiar to GCSE Science and Chemistry students, not only because it is used in pencil lead due to its slippery nature and black colour, but also because its unusual structure is frequently the subject of GCSE questions.

graphiteGraphite is made of carbon atoms, arranged in layers in a giant covalent structure. While the bonds between adjacent carbon atoms are strong covalent bonds, the bonds between layers are weaker enabling slippage to occur. Further, the structure includes “free electrons” enabling graphite to conduct electricity. This is highly unusual for a covalent, non-ionic structure, as is its high melting point. Graphite is also used as part of nanotubes in tennis rackets.

 In some senses graphite is like diamond because it is also a giant covalent structure of carbon atoms, but in diamond there are no layers, just a continuously strong bonding arrnangement making diamond much harder. And of course you’d look a bit silly with a pencil for an ear-ring.

What other GCSE substances are there on planets in our solar system? Well, on many planets we can find an iron and nickel crust, and on Mars recent photogrpahs indicated the possible presence of both water and methane, with the water creating channels that are still changing in appearance.  This indicates that the water is still moving and not completly frozen, perhaps because of hydrated salts, which lower the melting point.

BowieThis, together with the presence of methane (carbon with four hydrogens – natural gas – and another GCSE bonding question) indicate that Life on Mars is possible. And so I need no excuse to include a video from the sadly missed David Bowie’s Life on Mars, one of the great rock records.

So it may not get you any more marks, but in a GCSE question it would surely look cool to your examiner that you knew that graphite had been found on Mercury and methane and water on Mars !

As a footnote, a wonderful website called contains picture links to all the elements, including carbon of course – try it!

Colorado yellow river pollution in GCSE?

The VW nitrogen oxide and now CO2 saga shows that pollution is still a concern, and reminds me of the recent story of heavy metal pollution in Colorado turning a river literally yellow: could it feature in GCSE Chemistry?

coloradoTruth is stranger than fiction. The theme of the Simpson’s movie was that the USA Environmental Protection Agency (E.P.A.) turned into bad guys and erected a giant dome around Springfield in an attempt to contain the water pollution that Homer had started.

In August however the tables were turned when the real E.P.A, accidentally pumped polluted water into a Colorado river while clearing up a mine. The pollution spread and extended over the border to New Mexico and the river turned yellow, becoming contaminated by heavy metals including lead, iron, zinc, copper, mercury and arsenic. Read more in the BBC’s account and CNN broadcast

Could pollution and heavy metals feature in GCSE chemistry? Well, it is at the margins, but yes they could. Heavy metals are amongst the transition metals of groups 2 and 3 of the periodic table, of which students must know the layout. 

Pollution as a whole is often featured these days in GCSE chemistry as a supplementary question, sometimes around acid rain. For instance one specific sample question was to “list the advantages and disadvantages of mining metal ores” to which a good answer might include “they can cause difficulty in clearing up once closed down, as shown in a recent incident in America”. It is worth students talking to their Chemistry teacher about the incident.   

Water purity sometimes crops up as well in GCSE, with one of the purposes being to remove heavy metals.    

It remains to be seen whether the American Government will fine itself several billion dollars, as they did to BP after the Gulf of Mexico oil spill (I declare an interest as a BP shareholder and former employee !) The affected Narajavo Nation for instance is already threatening to sue. It reminds us in Europe of the sad decline in colour of the Blue Danube.

easyriderTo finish on a lighter note, while Yellow River certainly was not a Heavy Metal record (it was by UK Group Christie) it is worth mentioning the possible origin of the term Heavy Metal. In Chemistry it is because the metals mentioned have high relative atomic mass. In music it is probably from the phrase “heavy metal thunder” in Steppenwolf’s “Born to be Wild” which featured in the biking film Easy Rider (above) , or from the title of Iron Butterfly’s 1968 album “Heavy”. Many songs claim to be the first truly heavy metal song, the most famous of which are the Kinks “You Really Got Me” and  the Beatles’ “Helter Skelter” at the end of which Ringo, after drumming so loudly, famously agonises “I’ve got blisters on my fingers”!

GCSE-taking teenagers (OK, of the boy variety) will probably associate  heavy metal most closely with AC/DC, and their soundtracks from the films Iron Man 2 (Robert Downey Junior) and Battleship ( Liam Neeson, Rhianna), or from the video games like Rock Band and Mad Max. Parents may be interested to know that AC/DC’s Back in Black is the second highest selling album ever behind Michael Jackson’s Thriller, and ahead of Pink Floyd’s Dark Side of the Moon, Whitney Houston’s Bodyguard, and Meatloaf’s Bat Out of Hell. Could there be such a diverse set of albums?

Headmaster suspended for letting pupil take exam early

A headmaster in Wolverhampton has been suspended, and then reinstated after an enquiry, for allowing a pupil to take a GCSE English exam a day early. The reason seemed a little lax, namely to allow the pupil to go on holiday with their parents.

One assumes the enquiry involved checking his phone records and those of his friends in the few hours after the exam!

It reminds me of another “exam made easier” story from June when the answer to one GCSE question was helpfully supplied in another question, in the same paper. An AQA Chemistry paper contained the following:

2a. Fill in the blank. Limestone is mostly calcium ————
5b Limestone is made mostly of calcium carbonate…

In terms of making exams easier, let’s finish on a more serious note, well slightly more serious; allowing computers in exams.

googlemathsThe head of the OCR exam board suggests that Google be allowed in exams. The responses have varied from “ridiculous” and “rubbish” to “it would test resourcefulness and initiative rather than just your memory”.

Another proponent of the use of computers in exams is Dr. Sugata Mitra who conducted the famous experiment to place a computer in a hole in the wall adjacent to an Indian slum and found 7- year old children very quickly picked up skills with no assistance. It is a topic that won’t go away. But that is for another blog!

Could you wear Pink Floyd in Physics exam?


I, like many aging rockers, proudly wear my Pink Floyd Dark Side of the Moon T shirt around the house.

So the question is, could a pupil wear this in a GCSE physics exam, and would it be of any use?

The answers are possibly, and yes.

Most pupils have to wear school uniform in GCSE exams, but it is possible some don’t (think re-takers or adult education).  But it is likely they would have to change or cover up, as “notes that would help” are precluded.  If however all those barriers were crossed, would it actually be of use? The answer is definitely yes. Useful both to you – and here’ s the catch – everyone else!

A very typical Physics GCSE question might be to predict and explain the path of white light entering a prism, and what would the positions of red and violet light be?

The T-shirt goes a long way to answering the question.

White light disperses as it enters a prism because different wavelengths of light refract by different amounts. Unlike a rectangular block, the boundaries of a prism are not parallel so the different colours of different wavelengths do not recombine.

But why is red at the top of the spectrum and violet at the bottom, and how do you remember which way round it is? Well, red has the longest wavelength of the visible part of the electromagnetic spectrum and is refracted i.e. bent the least, whereas violet has the shortest wavelength and is bent the most.

How could you remember this? For the exam you certainly need to learn the key parts of the whole of the electromagnetic spectrum from radio waves down to gamma waves; and within that, the order of the visible light colours – but how to do that? 

Well, you could wear the T shirt and be asked to leave the exam room. or use a technique close to the Mathemeteer’s heart – the mnemonic (always wondered how to spell that!)

Richard of York Gave Battle in Vain       Red Orange Yellow Green Blue Indigo Violet!

Pink Floyd’s chorus children famously sang “We don’t need no educashion”. Oh but you do!

Maths and the NPL Music Society

NPLConnections between Maths and Music are many and varied. Here is another, indirectly at least.  In Teddington the National Physical Laboratory and “Home of Measurement” plays host to the NPL Music Society, where small classical music lunchtime concerts are given in the Scientific Museum, Bushy House.  These concerts feature pianists, singers, small chamber groups and recently a harpsichordist who perform in a room overlooking Bushy Park, while surrounded by all manner of scientific measuring instruments. The next performance is Thursday October 22nd   2015, featuring Haydn and Granados.

Meanwhile at Waldegrave School in Twickenham, a representative from the NPL recently gave a talk to the 6th Form Physics Group on the subject of standardised time zones and time measurement.   Before the advent of the railways in the mid-19th century there were no standard time zones in the UK, and time differences between cities could vary by as much as 20 minutes, as explained in this article.

The NPL is home to the first Atomic Clock developed 60 years ago this year. The Caesium atomic clock is accurate to 1 second in 158 million years.

Maths GCSE includes questions on converting ratios with different units into “1 to n” ratios. It is an extreme example, but in this case the accuracy would be 1 to 158, 000,000 times the number of seconds in a year, which is 31,556, 926 (you didn’t know this? Nor did I!). Making  :  4,982,688,000,000,000 in all, or about 1 in 5 million billion. 

If you find that mind boggling consider this: the next generation of atomic clock will make the above look piffling, and will be 100 times more accurate, making an accuracy of 1 second in the age of the universe. I cannot get my head around that! It presumably would enable us to figure out if the Big Bang was late in coming, but that is another story, although Big Bang is actually covered in GCSE Science and Physics and also in Religious Studies.  More on that another time.

Meanwhile back where we started, here is a link to an extensive review of a NPL concert from a couple of years ago and a more recent advert for a December 2015 concert featuring Natasha Hardy.