STS Scope includes SSERC Science, Technology and Safety Bulletin

For those working in science or technology education ISSN 0267-7474

ISSUE 207 Mucking out the midden

CONTENTS More people are staying on at school and taking What happens after school? Not everyone goes part in tertiary education. Workers by hand are 1 Editorial on to university or college. The old style seen as being of lower status than workers by apprenticeship has vanished into the mists of time 2 News & comment mind. Manufacturing industries are vanishing. As replaced by skillseekers, YOPs or whatever a farmer’s daughter I can barely stand to think 3 Health effects of acronym is used for youth training today. about the state of agriculture. There are fewer Employers have to be bribed to take on trainees. low-level time-served plumbers, plasterers and other radiation tradesmen than there used to be. Most of them Even at university, arts subjects and pure science 7 HSE guidance are over 40. generally have higher status than applied science. It takes fewer Highers to get into an engineering 8 PIC & LCD display It is said that it is easier to get a home visit from a course than to get in to study English or history. 9 Solution bumping general practitioner than from an electrician. Why? Do we really need more English and history Problems arise because trades are not considered graduates? There are exceptions: medicine is an 10Anodising important enough to regulate effectively. An Radio transmitter applied science but are the doctors who work in incompetent gas fitter can kill just as many the hospital of so much more value than the civil 11Laser offer people as an incompetent doctor. Serious rail engineers who built it? Is the dentist who uses accidents have been caused by maintenance 12 Radiation the drill more important than the electrical failures. The rise of hospital-acquired infections engineer who designed it? detectors seems to be proportional to the decrease in the 13New ICT packages number of cleaners. Is this all cost-driven? After all it’s possible to teach English with a handful of cheap paperbacks. 14Floras The attitude starts at school. Primary school Practical subjects need specialised facilities and 15Phenomenology children hardly ever do any cookery, or simple special teachers. But if we are to be served lattes science or basic carpentry because the schools 16Trade News by graduates isn’t it better that they graduated either don’t have the facilities or are too from Costa College? concerned about health and safety risks. But The Bulletin is playgroup-age children can saw and nail bits of During the ICS’s tourism debate in Cupar, we published by wood under supervision without incident. heard that visitors to Scotland are disappointed by SSERC, the quality of service. In the USA and in St Mary’s Building, Scottish secondary school children have a few 23 Holyrood Road, periods of home economics and technical continental Europe the chefs, waitpersons and Edinburgh, EH8 8AE subjects in first and second year. Some carry on to cleaners seem to care more about pleasing the Tel: 0131 558 8180 Standard Grade and Highers but the departments customer. Is that because they are nicer people, Fax: 0131 558 8191 are not highly regarded. My youngest daughter is because they are paid more or because their E-mail: [email protected] seriously concerned about the lack of respect she society values their work? Managing Editor: will be given for her Standard Grade craft and My final example of the proposition is a particular John Richardson design. She and her classmates spent six months hobbyhorse of mine. This is almost a joke but if I Copyright is held to be waived only for bona-fide of physical and mental effort planning, designing had spent 18 years in Cornton Vale having educational uses within and making complex and functional units from current Scottish member murdered four people there would be an army of EAs, schools and colleges. wood, metal and plastic. She made a lovely piece of furniture. CONTINUED OVERLEAF SSERC Bulletin 207 Winter 2002 207 - 1 News and comment

Diary dates in the Scottish Curriculum and Science ASE Scotland - Annual Meeting International Science Conference for the 21st century. There is also going The Science Education 20:20 Conference to be a special NQT/PGCE student The 2003 annual conference and the is to be held in the International afternoon on Wednesday. Annual General Meeting of the Scottish Branch of the Association for Science Conference Centre in Edinburgh from Institute of Biology Events 5th - 7th March, 2003. Organised by the Education will be held in Aberdeen on Scottish Executive, the Science Education The Scottish Branch of the Institute of 7th - 9th March 2003. The Conference 20:20 Conference will look forward to a Biology has arranged a day course for will be based at St Machar Academy and world where teaching and the school biology teachers on Protein Technology The Patio Hotel, Aberdeen. The ASE Scot- curriculum will have radically changed. on the 1st of February 2003 at the Quest land Technician’s Conference will run as The event will raise the profile of science Biotechnology Laboratory in Dollar part of the Annual Conference over Fri- education, recognise the importance of Academy. Details from Peter Anderson day 7th March and Saturday 8th March. public understanding of science and (see Address List). The branch has also A wide range of talks, lectures, work- highlight concepts of risk management announced the date for the 8th Biology shops, seminars and visits have been in science. This conference is an event Teachers’ Day. That event will be held on organised to support science courses for teachers, educationalists, scientists Tuesday the 3rd of June and the venue, from 5-14 to Advanced Higher. There will and, indeed, for anyone with a passion as usual, will be the University of Stirling. also be a wide range of exhibitions of for science. Further details, including of the pro- books, publications, apparatus and other gramme, will be posted on our website resources to teach science. A full pro- A number of internationally-renowned as they become available. speakers are to address the conference, gramme for these ASE conferences and a from astronauts to academics, including Chemistry Teachers’ Day booking form are inserted in this issue of the Bulletin. Sir James Black, Sir Kenneth Calman, The National Scottish Meeting for Professor Richard Dawkins, Dr Bonnie Teachers of Chemistry organised by the PPP out-takes Dunbar, Sir Gareth Roberts and others. Royal Society of Chemistry and St PPP - as we all have come to know and IoP Congress 2003 Andrew’s University, supported by the love - stands for Public and Private Royal Society of Edinburgh, will again be The 2003 Congress will be held at Heriot Partnerships. In our recent experience, held at St Andrew’s University on 30th occasionally the final “P” might be better Watt University from the 23rd to the 27th May 2003. of March. The education programme for translated as “pear-shaped”. Lately, we’ve Congress 2003 will be extensive and Summer schools begun collecting PPP anecdotes relevant to science education facilities. Some of include ‘School Physics in Action’ each The residential Summer Schools in Bio- these may well be apochryphal. We do day from Monday to Wednesday and an technology, Chemistry and Physics are to hope so. Other stories carry the frighten- INSET programme. The latter is likely to be run again at the University of ing ring of truth. Many are traced back be a series of short one day events with Edinburgh in 2003. The dates have been to non-specialist architects in the private the opportunity to visit the Physics in set as 23rd to the 27th of June 2003. sector without any previous experience Action programme at the end of the day. There are also developing possibilities of school design. Thankfully, most such Specific days are being planned for for similar residential courses at other boobs are trapped out at the initial primary teachers, technicians and Scottish locations both for secondary design stages. Our favourite to date has secondary teachers. science specialists and primary teachers. to be the ordinary, double, under-bench We’ll do our best to keep you informed There will also be a series of workshops cupboard labelled: on topics such as: educational software as soon as we have any more detail on these. “For fumes”

EDITORIAL: Mucking out the midden continued from Page 1. professionals ready to help me re- But there is a strange dichotomy here. Catering staff, building trades, manufac- integrate into society and the world of Given the number of cross stitch and turing workers - few of them get the work. However, I stayed at home full- needlework magazines, there must be respect or rewards they deserve. We time for 18 years to bring up four people thousands of people sewing as a hobby need to re-examine our priorities and and what help was there? The black hole but with the closures of clothing start looking at the value we attach to in my CV was a problem and my life manufacturers in the Borders and other practical skills. Short-term cost saving experience didn’t count. areas there are very few sewing for a should not be more important than living. Practical skills are OK as a hobby long-term gains. Let me think – two toddlers, one toy – but not as a job? that’s conflict resolution. Three children We have to recognise that practical skills in different activities starting at 5 p.m. in In other countries, engineers and are of value to us as individuals and as a places three miles apart – that’s logistics technicians are respected, not the subject society. After all, every utopia needs and time management. I’m angry about of jokes. “What is the difference between someone to muck out the midden. an engineer and a technician? A how little value is given to childcare, This guest editorial was written by Ella Smith, parent and technician knows that you need to hit it arguably the most important practical School Board member. The article was first published in to get it to work, an engineer knows skill of all. Why should stay-at-home The Scottish Review, Summer 2002. The Scottish Review is where and how hard.” Other countries? parents be treated like second-class the journal of the Institute for Contemporary Scotland. citizens? Fifty years ago they were respected here. 207 - 2 SSERC Bulletin 207 Winter 2002 Safety

Health effects of low-level radiation The mainstream view that risk falls roughly in a linear fashion with dose is under attack from some who maintain that there is a threshold below which radiation is harmless, or even beneficial, and from other groups asserting that very low doses are extraordinarily dangerous.

There is sound scientific evidence that a large dose of ionising radiation is Radiation source Average annual dangerous, with a significant risk of the adult dose induction of cancer, or genetic damage in (mSv) progeny, or, if the dose is massive, death in the short-term. Below moderately high Cosmic rays 380 levels of dose the evidence trails off. It is Cosmogenic radiation: then a matter of conjecture as to what the 14C12 risk of harm, if any at all, actually might be. 22Na 0.15 Epidemiological studies show that risk 3H 0.01 falls with dose down to a value of about Primordial radionuclides (238U, 232Th, 40K, etc): 200 mSv. Below that value it is unclear External exposure 480 what the relationship is. The mainstream Internal exposure excluding radon: hypothesis is that risk continues to fall 40K 165 with dose in a linear or linear-quadratic U and Th series, ingestion 110 way down to zero (Fig. 1). It is known as 210Po 70 the Linear No-Threshold model (LNT). The 210Pb 21 model implies that all ionising radiation, U and Th series, inhalation 5.8 no matter how small, is potentially harmful. Notwithstanding that, for Radon and progeny: 222 pragmatic reasons it is customary for an Table 1 Rn indoors 1010 222Rn outdoors 95 extremely low dose to be regarded as Average annual dose 220Rn indoors 84 negligible, trivial, or tolerable, provided from natural 220 that it is very much lower than a dose radiation sources Rn outdoors 7 from background radiation (about 2.4 mSv (UNSCEAR 2000). a year on average). There are many scientists who do not defence mechanisms in biological systems. That sets the scene for the debate. As it accept the LNT model. It is under attack This effect is known as radiation hormesis. proceeds, there is no meeting of minds from both sides. One group, with many Biological systems are known to show between the disputatious parties. In representatives in the US, France and the hormesis effects when under attack from reaction there has been much scientific Far East, hold that LNT greatly over- other hostile agents. It is seemingly akin1 endeavour on the health effects of estimates the risk at low doses, pointing to to the theory that a glass of red wine a radiation. From this, a lot is being learnt evidence for a threshold effect below day is good for you though no one is yet on how biological systems work and how which radiation would be harmless. Some advocating that we should pop a pill of disease is induced. In the rest of this go further, taking evidence for adaptive Caesium-137 a day to glow with health. report, we outline some of the research responses to assert that low doses are Anti-nuclear groups stand on the other findings and discuss the implications for beneficial because they stimulate natural side of the dispute, maintaining that LNT radiation protection. grossly underestimates the risk to health from low doses. Many of their attacks are Background based on scepticism. Their questioning Background radiation sets a standard can be healthily provocative because it against which any discussion on low level stimulates a considerable amount of radiation must be compared with. The scientific research and prevents annual dose to an adult is typically complacency. However it can be 2.4 mSv. At present, it is almost entirely unhealthy if it creates paranoia, or from natural sources (Table 1); less than irrational fear, or if the protests themselves 1% is from man-made sources, mainly are irrational. nuclear fallout from atmospheric weapons’ tests. At the height of the 1 A glass of red wine a day is not really a testing programme, in 1962, the annual hormesis effect. Alcohol in any quantity is dose from fallout (Table 2) was 5% of the harmful: benefit from the daily glass comes from relaxation, and the action of the dose from natural sources – an tannins in mopping up free radicals and experiment conducted on all biological sweeping them out of the system. A better species including the human race. Figure 1 Models illustrating the dependence example of hormesis is vaccination. of risk upon radiation dose.

SSERC Bulletin 207 Winter 2002 207 - 3 Safety

weak to strong. With the exception of the Average annual dose By comparison with cohort studies, ecologic study, measurement of exposure ecologic studies are seldom capable of and disease takes place at the individual yielding useful results because it is (microsievert) level. A weak study may not be able to generally impossible to make valid 19962 199 determine correctly the cause because of inferences from the information they confounders; a strong study will be less provide. Northern 1925 5. affected by random and systematic error. Cellular damage response Hemisphere The best known epidemiologic study is the cohort study with the survivors of the Health can be harmed by radiation from 3 Southern 579 2. atomic bombings of Hiroshima and types of biological damage: Hemisphere Nagasaki to find whether there is an • Cell death, in the sense that the cell association between radiation dose and Table 2 becomes unable to reproduce. Average annual dose from weapons increased risk of disease (cancer and testing (UNSCEAR 2000). cardiovascular). The main study looks at • Mutation in germ cells, leading to individuals who were within 2 km of the defects in progeny. Radiation in medicine and explosion hypocentres, matched by age • Malignancy in somatic cells, possibly industry and sex against those between 2 km and leading to carcinogenesis. The average contribution from medical 10 km from the hypocentres. From bomb yield and questionnaires to ascertain the Carcinogenesis is the most important irradiation received by the UK public is harmful effect of low doses of radiation. 370 mSv per year, whereas that from the orientation and shielding, dose estimates nuclear industry is about 2 mSv annually. have been obtained for 86,572 survivors. When radiation is absorbed in living The dose from medical treatment depends Information on possible confounders and things, the energy deposited is localized on the type of examination or effect modifiers has been obtained by along the tracks of the moving charged radiotherapy (Table 3). questioning individuals, and the incidence particles, disrupting chemical bonds of disease and mortality noted. The study within large molecules, and so causing Under the National Health Service Breast is ongoing. changes that are biologically significant. Screening Programme, all women between the ages of 50 and 64 years of age are This gives the scale of a cohort-type of If a photon is directly incident on DNA, invited for mammographic screening epidemiological study. There are other the photon is absorbed by the medium every 3 years. A single image is taken of similar studies with cohort sizes of 50,000 resulting in a secondary fast electron each breast, the average dose to breast or more on Sellafield workers, patients which directly hits and breaks the DNA tissue being either 2.0 mGy or 2.5 mGy per treated with what would now be strand. DNA can be indirectly damaged if film depending on the aspect. considered to be massive X-ray doses in the fast electron hits a water molecule therapeutic medicine, and workers in the (tissue is mainly water) producing a nuclear industry in the former Soviet hydroxyl radical. This free radical, with an Examination Typical Union. effective dose (mSv) Type of Ceonduct of study Exampl epidemiologic study X-ray examinations: Limbs and joints Eecologic study Disease rates ar Determining cancer (except hip) <0.01 correlated with exposure incidence and mortality Chest (single film) 0.02 prevalence in a population around nuclear sites Skull 0.7 defined by geography or Barium meal 3 time Barium enema 7.35 Cfase-control study Exposure status o Case-control study of lung CT head 2.3 individuals with the disease cancer amongst uranium CT abdomen 10 is compared with the status processors Radionuclide studies: with those who do not have Kidney (99mTc) 1 the disease (the controls) PET head (18F) 5 Cfohort study Follows up a group o Japanese a-bomb survivors' individuals with varying study Table 3 Effective dose for some radiological exposures through time to and radionuclide examinations monitor the occurrence of (Griffiths, BNES). disease Epidemiology Erxperiment (Seldom possible fo Following up cancer patients Epidemiology is the study of the ethical reasons) participating in randomized distribution and causes of disease by trials of the use of looking at groups of humans exposed to radiotherapy in treating the potential risk factors of interest. There Hodgkin's disease are 4 basic types of epidemiological study (Table 4), given in order of strength from Table 4 Four types of epidemiologic study, in order from weakest to strongest, with examples. 207 - 4 SSERC Bulletin 207 Winter 2002 Safety unpaired electron in its outer orbit, is There is now evidence of the role of steps could facilitate an aberrant highly reactive, chemically speaking, and instability in carcinogenesis. Most chromosome proceeding one further step diffuses to the DNA causing a strand break. tumours show instability. They show up towards making a fully malignant tumour. Two thirds of DNA damage from photon with multiple, unbalanced, chromosomal irradiation comes from the indirect action, aberrations. It is believed that there needs Adaptive response whereas most of the damage from alpha to be 6 to 8 separate stages to convert a It is quite normal for biological systems to particles and neutrons comes from direct normal cell into one with a fully malig- adapt in response to stress – a collisions and bystander effects. nant phenotype. Under a simple model, if phenomenon which is also called Single strand breaks are of little each mutation arises independently and hormesis. There is now evidence of an consequence since the molecule is readily at a frequency of 10-5, it becomes highly adaptive response in many biological repaired using the opposite strand as a improbable that a cancer could be systems after small doses of low LET template. However if both strands directly induced in a human lifespan. radiation (beta, gamma, x-ray), but not with opposite one another are broken, then the high LET radiation (alpha, neutrons). The 2 broken chromosomes may rejoin in such Bystander effect resulting dose from low LET radiation a way that either the cell dies, or an Whilst it has been hitherto accepted that tends to be reduced by between 1.5 and 2. aberration occurs. Cell death is not the main cause of heritable effects is a The induction of DNA repair is believed to harmful if the dose is low because the cell direct hit on DNA, there is evidence of a occur. However these processes do not death frequency will be low also. biological response occurring in cells universally happen. There is a which are not themselves directly dependence on dose rate. It has not been Genomic instability irradiated. Technically, it is now possible observed in cells from the pre-natal stage The genome is the source of genetic to target a single cell, or a localized part of in animal development. Also information in cells. It is encoded in the a cell such as the nucleus, with a hypersensitivity to radiation can DNA molecules and is continually under microbeam of alpha radiation, irradiating sometimes be seen. the target with a set number of particles – challenge by destabilizing factors: Summing up, it is doubtful if radiation even a single alpha particle – and protection should give credit to adaptive • Normal DNA replication and cell recording the result. One outcome of this response to radiation. division technique has been the demonstration of • Environmental stresses such as a bystander effect, i.e. some cells die or Genetic risks oxidisation mutate that had not been targeted. Furthermore it is possible to cause What is the additional risk of inducible • Exposure to genotoxic chemical agents mutations in cells by alpha particles that genetic diseases in human populations exposed to ionising radiations, i.e. over • Background radiation traverse the cytoplasm, not the nucleus. and above that which occurs naturally as To counter these attacks, cells have worked The bystander effect challenges the a result of spontaneous mutation? out elaborate ways for maintaining current model that direct damage to DNA Answers are emerging from experiments genomic integrity: is the only initiating event in triggering on mice, human data on baseline frequen- carcinogenesis. An inference from this cies of genetic diseases, population • To assure correct DNA replication model is that risk increases linearly with genetic theory and models, and some • To repair DNA damage dose. plausible assumptions. No statistically significant increases in adverse genetic • To control the progression though the Experiments on irradiating cell cultures in effects of parental radiation exposures cell cycle vitro with microbeams show a saturating response above a threshold dose: in one have been seen in a-bomb survivors in One positive outcome of genomic experiment, saturation occurs after one Japan. Geneticists now believe they can instability is that it can help genetic alpha particle. Irradiation of either a reconcile these findings with their present diversity. Negative outcomes are single cell, or different cells, with up to 15 understanding of the genetic risks of mutagenesis, which can change cell alpha particles do not produce additional exposure to ionising radiation. function or lead to death, and damaged cells, suggesting that for very There are 738,000 cases per 1,000,000 of carcinogenesis. low doses, there is a non-linear response. genetic diseases in the human population Genomic instability is often associated This is a possible mechanism for (Table 5). In Mendelian diseases, the with either the cell cycle going out of hypersensitivity at very low doses. relationship between mutation and control, or the DNA repair processes being It now seems that carcinogenesis by disease is simple and predictable. In altered. The p53 tumour suppressor gene radiation is not down to one mutation multifactorial diseases (e.g. congenital has a key part in how a cell responds to occurring in a specific gene in a single cell, heart defects, cleft lip, etc.) there are no DNA damage. It works in cell cycle control, which then gains a selective growth simple patterns of inheritance, but these delaying the cycle to give the cell time to advantage. Rather, radiation may induce a tend to run in families. repair DNA damage before DNA replication process of genomic instability in many The incidence of mutant genes in the or mitosis. It also helps to remove heavily cells in the irradiated tissue, boosting the population tends to be stable, being damaged cells by apoptosis, the deliberate rate at which multiple mutations would balanced between the rates at which killing off of sick cells. However if the p53 occur. Radiation could thus act at any spontaneous mutants enter the gene pool gene is itself inactivated, perhaps by stage in the development of a tumour. As in every generation and the rates at which radiation damage, then these functions we have said, there are 6 to 8 stages they are eliminated by natural selection, i.e. would not be performed. between the first and final instability. A through failure of survival or of radiation exposure during any of these reproduction. If there has been irradiation,

SSERC Bulletin 207 Winter 2002 207 - 5 Safety the balance is disturbed by the influx of induced mutations, but the prediction is Drisease class Baseline frequency pe Risk per Gy per 106 that the population will eventually reach a 106 live births progeny new equilibrium between mutation and selection. M0endelian 204,00 7o5 t01,50 Radiation-induced mutation tends to differ in kind from spontaneous C0hromosomal 4e00 Subsumed abov mutations. The former tend to be mainly random deletions in DNA causing loss of Mulifactorial: function; the latter include point mutations, DNA deletions and large multi- C0hronic 6050,00 250 to 1.20 gene deletions, causing loss as well as C0ongenital abnormalities 600,00 200 gain of function. Most human disease- causing genes are not of the type T0otal 7038,00 3000 to 4,70 produced by radiation. Radiation-induced genes tend not to recover in live births. If Total risk per Gy 0.41 to 0.64 they did, they would show predominately expressed as per cent of as multi-system developmental baseline abnormalities. These factors explain why radiation induced genetic disease has not Table 5 been found in humans. Estimates of genetic risks to the first generation progeny of a population sustaining continuing exposure to low-LET, low dose or chronic irradiation. Summing up, the risk per Gy is only about 0.41 to 0.64% of the baseline risk of uniformly distributed, but could be are especially insidious. Estimates have 738,000 per million live births, a very small concentrated in a single radioactive been made by Greens that the risk of proportion indeed. fragment, resulting in surrounding tissue harm from man-made radionuclides could getting a very high dose. So although the be 500 times greater than the present LNT debate average whole-body dose would be very protection system admits. However this The above report delineates the main low, the localized dose would be very high, does seem unlikely in view of the massive areas of research into the effects of low from which they infer that the risk of harm dose of man-made radionuclides the level radiation on health. The findings are from cancer induction would be very high entire population has been receiving from complex, confusing and sometimes also, and certainly very much higher than fallout over 5 decades – an epidemi- contradictory. It is therefore possible for the tiny whole-body dose would appear ological experiment of worldwide scope. lobbyists from one side of the debate or to indicate. However a recent review of The middle ground of the debate is another to cherrypick a basketful of many experiments into the risks from hot- occupied by the national and internation- results and make seemingly convincing particles failed to reveal the excess risk the al scientific bodies charged with advising cases. For instance the radiation-hormesis anti-nuclear group believes is plausible. governments on setting radiation camp have trumpeted an ecological Another argument from the Greens is that protection regulations. These include epidemiological study into the incidence man-made radiation is bad, natural UNSCEAR1 and ICRP2. They hold the view of cancer in US states showing the radiation is OK. Following this line: 210Po that, taking aboard all of the evidence to decrease of cancer mortality rates with and 40K are tolerable, 137Cs, 90Sr and 239Pu increase in radon concentration. Ergo the 1 UNSCEAR: United Nations Scientific are bad. Somehow humans have evolved Committee on Effects of Atomic Radiation. linear-no-threshold model does not hold, to tolerate, by adaptation, radiation from 2 ICRP: International Commission on they say. In another example, the Greens natural radionuclides, but man-made ones are using the finding that the incidence of Radiological Protection. cancer in communities living within 1 km Bnand of concern Deescriptio Level of dos of the Irish Sea is higher than average as evidence that a little radiation is bad for you. For the convenience of their Bsand 6 Sleriou >100 x norma arguments, ecological studies give plausible results when they suit the case Bhand 5 Hlig >10 x norma the lobby groups are advocating, ignoring the fact that they are generally incapable 1-10 mSv of yielding sound scientific results. Bland 4 Norma (Typical natural One of the main props of the radiation background) hormesis group is adaptation. But there is evidence for and against adaptation. Even Bwand 3 Llo >0.1 x norma if adaptive effects help to ameliorate harm from low doses to the general population, Bland 2 Tlrivia >0.01 x norma there is a small group of hypersensitive individuals in need of protection. Beand 1 Nlegligibl <0.01 x norma A big issue with anti-nuclear lobbyists is the idea of hot-particles, that if radiation is Table 6 ICRP proposals: Bands of concern about individual effective doses in a year. inhaled or ingested it is unlikely to be 207 - 6 SSERC Bulletin 207 Winter 2002 Safety date, the best position to adopt for the Recent proposals from ICRP classify Acknowledgement present is the linear no-threshold (LNT) radiation exposures by estimating how This report is drawn from papers read at the 4th model, that the risk of harm diminishes the risk compares with background International Conference of the British Nuclear from the well understood values at radiation (Table 6). If the estimated dose is Energy Society held at Oxford in September moderate to high doses in a linear or less than one hundredth the value of 2002 to debate the health risks of low-level linear-quadratic fashion to zero at zero annual background radiation, then the radiation. Papers were by M Thorne, C Griffiths dose, with no threshold effect. The dose would be classified as negligible, (Royal Hallamshire Hospital), G Howe (Columbia principles of radiation protection which implying that no further effort should be University), E Hall (Columbia University), J Little follow from the LNT model are: (Harvard School of Public Health), K Price (Gray expended in trying to reduce the risk any Cancer Institute), C Streffer (University of Essen), • No one should be exposed to further. Under this proposal, any dose less M Charles (University of Birmingham), m radiation unless there is a justifiable than 10 Sv would be negligible. The K Sankaranarayanan (Leiden University), R Clarke reason. typical dose to the demonstrator of a (ICRP), R J Preston (US Environmental Protection school experiment with either beta or Agency), M Pollycove (University of California), • The dose to the irradiated person shall gamma sources is about 100 nSv. With the C Busby (Green Audit) and N Gentner be kept as low as reasonably best judgement we have today, the risk is (UNSCEAR). achievable – the ALARA concept. negligible.

New HSE guidance Electrical testing protection, test equipment specification, the mist, aerosol or vapour, through skin power supply earthing and legal contact, through cuts and by ingestion. The HSE have recently published two 4- requirements. Health effects include skin disorders, page information sheets [1, 2] and a 14- respiratory illnesses and skin cancer. Also page booklet [3] all on safety in electrical The booklet [3] covers the same scope, but in more detail. On the thorny issue of oil-soaked clothing and oily rags kept in testing. They would be relevant to any- overalls can cause cancer of the scrotum. one working in or operating a technician competence, we are told, “When setting up repair centre, or in any school where elec- a testing area, it is important that people Addressing this hazard, the HSE have trical equipment was repaired or tested. who are electrically unskilled or inexperi- recently published a free leaflet for enced are protected from electrical danger employees [1] and manual [2], which The scope of the information sheets at all times”, and “someone’s personal includes a set of 8 instruction sheets for covers the servicing and repair of, electrical competence should not be relied employers to issue to staff. These 8 sheets respectively, domestic appliances [1], and on as their main protective measure”. As describe what you need to know to audio, TV and computer equipment [2]. with the Good Book itself, these HSE control the hazard (storage, water-mix For greater relevance to the school leaflets provide much to reflect on. mixing methods, sump top-up procedures, workshop or laboratory, the scope of the sump cleaning and clearage, and sheet on domestic appliances can be References spillages). taken to mean electrical equipment. 1. Safety in electrical testing: Servicing and References When carrying out a risk assessment for repair of domestic appliances Engineering electrical testing, the four questions to ask Information Sheet EIS35 HSE Books 2002 1. Working safely with metalworking fluids are: 2. Safety in electrical testing: Servicing and Guidance for employees INDG365 repair of audio, TV and computer equipment HSE Books 2002 • Can the work be done with the Engineering Information Sheet EIS36 HSE 2. Working safely with metalworking fluids equipment dead? Books 2002 Good practice manual HSG231 HSE Books • Is it really necessary to work at 3. Safety in electrical testing at work General 2002 ISBN 0 7176 2544 3 (£10.50) dangerous voltages or currents? guidance INDG354 HSE Books 2002 ISBN 0 7176 2296 7 • Have suitable precautions been taken Superwool 607 - to avoid danger? Metalworking fluids Update • Is the person doing the work Metalworking fluids are used to lubricate competent for that type of work, or, if and cool metals during machining and to In our last issue (Bulletin 206) we reported not, adequately supervised? help carry away debris such as swarf and on the hazards of thermal insulating fine metal particles. They can also improve ceramic wools, recommending that It is essential to set up a safe work area for machining performance, prolong the life traditional wools should, for many testing where access is limited to what is of the cutting tool and protect the applications be replaced with Superwool strictly necessary. A safe work area would surfaces of workpieces from corrosion. 607, a new material shown to be free of carry no risk of unauthorized entry. If such carcinogenic properties. When the article an area cannot be set up, then work at So far as we understand, metalworking was writen, it was unavailable from dangerous voltages or currents should fluids are rarely used nowadays in educational suppliers. We have now been not be undertaken. This may restrict the Technical departments, although they may informed that Superwool 607 can be scope of electrical testing in schools, still be used with machine hacksaws or in purchased from Philip Harris Education: limiting it to technician service centres. turning large pieces of metal. Superwool 607, blanket, Other issues addressed include live These fluids are harmful to the operator. 600 x 300 x 25 mm (about 500 g), working, use of temporary insulation, RCD They can enter the body by inhalation of Cat. no. C0H71636, £10

SSERC Bulletin 207 Winter 2002 207 - 7 Technology PIC and display Messages can easily be produced on liquid crrystal displays driven by PIC controllers.

Liquid crystal displays (LCDs) are within show: serout 7,N2400,(1) ‘ show message 1 the ken of pupils, from the ubiquitous pause 500 mobile phone to games’ consoles or microwave ovens. There are two types of serout 7,N2400,(2) ‘ show message 2 LCD display. In one, the picture is made up pause 500 of a series of dots forming a graphical goto show display; this type is used on mobile phones and some game consoles. The second uses words forming a text display, usually in the form of 2 to 4 lines of a set Figure 2 Picture LCD showing temperature number of characters; it is mostly found in with thermistor. vending machines. The complicated This ability to predefine a message greatly circuit and cost have precluded their use reduces the display text stored within the with school project work, particularly PIC or Stamp. They are stored, instead, those with a graphical display. Now within the LCD module. Messages 1,3,5,7 thanks to the interest of schools in Basic appear on the top line of the display and Figure 3 Picture LCD showing Welcome to Stamp and other PIC controllers a textual messages 2, 4 and 6 on the bottom line. the TTA Conference. serial LCD (Fig. 1) is available at a Examples of the necessary commands are reasonable price. This serial LCD is a 2 row, shown below: Presentation 16-character per line display offered as a modular package with all necessary init: pause 500 The PICAXE project board and the LCD circuitry and the option of a real time module were built into a spare plastic clock. The microcontroller on the module main: serout 7,N2400,(253,1,” Welcome to the “) ‘ instrument housing. We decided on 4 pre- carries out the complex driving show on top line defined messages plus date and time. instructions letting pupils use simple pause 1000 These account for the 5 push switches BASIC commands to output messages ‘ time to write text seen in Figure 4. The toggle switch allows from a variety of systems. These include the batteries to be switched off when the PICAXE, Basic Stamp and PIC-Logicator. All serout 7,N2400,(253,2,” TTA Conference “) box is not in use. Figure 5 gives an idea of of the following instructions were carried ‘ show on bottom line our internal layout. out using PICAXE-18. pause 1000 end The predefined message “ Welcome to the TTA Conference” is now stored in the LCD module. To retrieve and display the message the following program could be used: init: pause 500 Figure 1 Picture LCD showing date and time. show: serout 7,N2400,(254,1) ‘ clears LCD display Figure 4 Box with PICAXE board and display. Programs pause 500 A simple BASIC program to send the serout 7,N2400,(1) ‘ show message 1 message “welcome” to the LCD would pause 500 need a command: serout 7,N2400,(2) ‘ show message 2 serout 7,N2400, (“welcome”) pause 500 or any other text message up to 16 goto show characters per line. A more practical use could be to output the variable, If some form of switch (pressure pad or temperature. optical switch, etc.) were to be employed serout 7,N2400, (“Temperature = O”#temp) to start the display, the program would then read: Messages init: pause 500 A most useful aspect of the module is the main: serout 7,N2400,(254,1) ability to store up to 7 user-predefined messages, remembering that each pause 500 message must only include 16 characters. if pin1 = 1 then show Figure 5 PICAXE board inside box.

207 - 8 SSERC Bulletin 207 Winter 2002 Technology / Chemistry

Alarm alarm to a specific time interval, say the Summary A further useful addition to the module is end of a school 40 minute period, the Using only a few of the features available an optional real time clock with an alarm program would be: with a serial LCD and clock module pupils facility. This enables pupils to display time init: pause 500 will be able to incorporate time and on the LCD module or, using the alarm, to display into their work with PICAXE, Basic trigger outputs at periods between main: serout 7,N2400, (253,9,”00:40:00 “) Stamp or PIC Logicator. ‘sets time 40 mins 10 seconds and a year. The lithium cell in Further details on the LCD module can be the clock module should maintain pause 1000 found on www.rev-ed.co.uk accurate time for up to 10 years. To set the end The Serial LCD & Clock module is supplied by Revolution Education Limited (stock no. AXE 033, price £12.00).

Bumping during the preparation of potassium trioxalatoferrate(III) Some improvements are recommended to the method of preparing potassium trioxalatoferrate(III) (Advanced Higher Chemistry PPA, Unit 1, PPA 1)

on this. It is useful to roughly calibrate So the general advice on good practice in “Then nightly sings the staring your hotplates by trial and error and mark preparations is: owl: the setting at which water just boils gently. (i) to stir well and ‘Tu-who; The following points relating to the procedure were identified: (ii) when adding reagents, to initially Tu-whit, Tu-who’ – A merry make small additions with efficient Step 4 - When the beaker is placed on the note, mixing and check that the reaction is hotplate adjusted to a low rate of heating occurring and that most of the portion While greasy Joan doth keel as per instructions (setting 3 on our just added has been used up before the pot” hotplate), then this Step can take a long making the next addition. time, - too long. It is possible to heat the solution faster (setting 5 on our hotplate), LOVE’S LABOURS LOST Shakespeare “Make the gruel thick and slab; but then stirring must be continuous to prevent the solution from splattering, the Add thereto a tiger’s cauldron, We recently received a report of a problem best method being to use a magnetic regarding this PPA. This incident occurred stirrer hotplate. Hand stirring with a glass For th’ingredience of our during Step 4 of the Procedure, when rod will do the job, but must be cauldron. continuous. bringing the aqueous solution and the Double, double toil and yellow precipitate of iron(II) oxalate Step 6 - Once you have decanted off the trouble; (ethanedioate) to the boil on a hotplate. It hot water, let the solution cool slightly was reported that the solution sometimes before continuing. We found the Fire burn, and cauldron erupted violently and ejected the contents temperature of the beaker at this point to bubble.” some distance, and that this happened be well above 40 °C. before reaching the boiling point. We MACBETH Shakespeare 3 have taken the opportunity here to Step 7- Addition of the 10 cm of highlight a second potential problem potassium oxalate (ethanedioate) solution which can arise during the addition of cooled the beaker contents to a New chemical nomenclature! hydrogen peroxide solution in Step 8. temperature of 35 °C. The solution was heated until it reached 40 °C and then Recently spotted on the wrapper of a bar We repeated the preparation several times removed from the hotplate. of soap are two names based on yet and confirmed that the problem exists, another system; but that it can be overcome. Hotplates are Step 8 – The initial addition of the 20 “Sodium tallowate and sodium cocoate”. often difficult to control; they are fine for volume hydrogen peroxide needs to be in 3 hard boiling and refluxing or for slow amounts of less than 1 cm as the Here sodium cocoate (presumably either simmering, but unless you know the oxidation is highly exothermic and the sodium dodecanoate or hexadecanoate or peculiarities of the particular hotplate, can temperature of the beaker contents can perhaps a mixture of the two) combines be difficult to control at in-between rates rise well above 40 °C. The reaction is very the new and the old; the IUPAC ending of of heating. The delay in response to any vigorous and the liquid can froth over. We “oate” has been grafted onto the cocoa change of the heat setting, whether an would recommend cooling the beaker in a palm tree, indicating the natural source of increase or decrease, often catches out the cold water bath during the hydrogen the substance. Would sodium uninitiated or the impatient. The surface peroxide additions until more than half of rhubarbanoate or sodium sorrelanoate be temperature of a hotplate on a high the hydrogen peroxide (approximately alternatives to sodium ethanedioate or 3 setting is typically in excess of 300 ºC and 13 cm ) had been added. Thereafter the would sodium willowate tell us more even water, if small in volume, will bump addition can probably be made more about its origins than sodium 2- rapidly. hydroxybenzenecarboxylic acid?

SSERC Bulletin 207 Winter 2002 207 - 9 Chemistry / Physics

Anodising again ready), and followed the method for dyes obtained good results with them. Winsor we told you about in Bulletin 205. The and Newton’s range of drawing inks are anodised aluminium turned out an supplied in 14 ml bottles costing £1.99 We’ve gone Naturalist! antique gold colour (green/yellow/brown). each. Dilute 2 ml to 75 ml using distilled Our resident chemistry guru has been Who says chemists and nature can’t get water and heat. We obtained good results having fun suggesting possible sources of along? Maybe the beetroots and the with Vermilion, Ultramarine and Violet. dye. He supplied some red onionskin grass might work too! If you’re trying the dyes - Dylon from onions grown in his allotment. Dye scarcity Multipurpose dyes work best. (Don’t try Never able to resist a challenge, we boiled cold water dyes because they don’t work.) Since publication of our article in Bulletin the skins for an hour in distilled water till We used Dylon No 33 Kingfisher, Dylon No 205 we have experienced difficulty in the water turned a muddy red brown 15 Windsor Purple and Dylon No 34 Forest obtaining the inks used. Pelikan are colour, decanted the liquid into another Green - all gave good results. These cost reducing their range and supplies are beaker, popped in a piece of anodised approximately £1.50 depending on where scarce. We’ve tried some others and have aluminium (we just happened to have one you get them.

Signals from a radio transmitter If a single turn of wire short circuits the low impedance output of a power signal generator tuned to produce 100 kHz, or thereabouts, then it is possible to generate and transmit an RF signal.

Communicating by radio is one of the Sub-system Apparatus Example of, or Comment themes in Unit 1 of Standard Grade or function specification recommendation Physics. In one of the standard practical on, apparatus activities1 , a radio transmitter is set up in the classroom to broadcast a radio signal. Radio Power signal Unilab Power Signal Frequency output = The pupils monitor the signal by frequency (RF) generator with Generator 062.101 100 kHz nominal. connecting a CRO to test points on the oscillator amplitude Amplitude transmitter; an amplitude modulated modulation (AM) modulation facility waveform should be seen. However there facility switched on. is now no radio transmitter on the Gain = max. educational market. The sole product that used to be available (Irwin, EB0058) is now Audio Power signal Harris S Range Frequency output = obsolete, leading to some schools being frequency (AF) generator, Power Signal 1 kHz nominal. unable to perform this activity. We are oscillator preferably with dc Generator DC offset = 0 mV. grateful to Alex Marsh, of Unilab, for offset Gain = low. suggesting this method. It requires the Apply output to AM apparatus listed in Table 1. Although the 2 input of RF signal generators recommended in the oscillator. table became obsolete at the beginning of this year, they are both very common; Aderial 4 m wire forme Connect wire across other models may be substituted. into a single turn low impedance loop in a vertical output of RF Procedure: plane oscillator 1. Set up a radio receiver about 2 to 3 m Waveform CRO Use External from where the RF oscillator is placed. monitor >10 MHz Trigger. Tune the radio receiver to a long wave bandwidth Trigger off signal broadcast programme, showing that from AF oscillator. the receiver works. Rnadio receiver Demonstratio Unilab Alpha boards: Power off 5 V dc 2. From bench tests in SSERC, the Unilab radio receiver kit Tuned Circuit 020 regulated supply Power Signal Generator 062.101 is Radio Receiver 220 capable of delivering greater power Power Amplifier 221 than other types of generators. There- Ferrite core fore this is our preferred apparatus for producing the RF carrier signal. Set the Lroudspeaker L,oudspeake Connect across frequency at near to 100 kHz and turn 4mto 16 oh output with the gain to maximum. Apply the impedance capacitive filter on signal to the Y-input of the CRO. Alpha Power Amplifier 223.221 1 SG Physics: Unit 1: Activity 10: Signals from a radio transmitter. Table 1 Apparatus for radio transmission and reception (using original Unilab product numbers).

207 - 10 SSERC Bulletin 207 Winter 2002 Physics

3. From bench tests at SSERC the Harris S Ctause Effec Range Power Signal Generator is the preferred instrument for generating an audio signal because its output Sweep up the audio signal frequency The audible tone from the receiver level can be shifted with a from 1 to 10 kHz corresponds to the AF oscillator potentiometer. It is perhaps the only signal generator with this feature. In Sweep down the carrier wave frequency The volume fades and strengthens, this demonstration ideally the audio from 100 kHz to 50 kHz suggesting that the receiver has broad- signal should have no dc offset so as band reception and picks up overtones to correctly modulate the RF signal. of the RF signal Because we find that the output from most models of signal generator has a Rseduce the carrier wave amplitude Radio receiver volume fade dc offset component, only the Harris signal generator can properly Rseduce the audio frequency amplitude Radio receiver volume fade modulate signals. Set the frequency to 1 kHz and apply to the AM input on the Radio Frequency oscillator. Increase the audio frequency amplitude Radio receiver volume fades because Connect this 1 kHz signal also to the (beyond the original, optimal setting) the RF signal becomes distorted External Trigger input of a CRO to stabilize the composite waveform on Retune the receiver to a radio No signal is heard from the laboratory the AF signal. Adjust the gain of the broadcast programme, then sweep transmitter 1 kHz signal so that the signal from through the audio signal frequencies the 100 kHz oscillator is a maximum without distortion. Displace receiver 1 to 2 m away from Radio receiver volume fades the transmitter 4. Short out the low impedance output of the 100 kHz generator with a length Rotate the plane of the transmitting Radio receiver volume fades of wire 4 m long. Arrange the wire to aerial through 90° form a loop in a vertical plane such Twist the transmitting aerial into a figure Radio receiver volume fades that a normal to the plane points at of 8 the radio receiver. We supported the wire with 2 wooden stools, one Replace the AF source with a Broadcasts speech upturned on the other. Retune the microphone receiver to detect the 1 kHz signal. Table 2 Radio transmission demonstrations. Demonstrations: It is suggested that the effects shown safety of others. The Wireless Telegraphy following practice: opposite (Table 2) should be produced (in Act prohibits unlicensed radio • If there is any safety critical system in every instance starting from the original, transmissions. However an amendment to the vicinity of the school laboratory, optimal setting of the transmitted signal): the Electromagnetic Compatibility do not operate this RF transmitter Regulations allows education equipment without checking with the operator of RF noise nuisance to cause an electromagnetic disturbance the other equipment that your signal Whilst modern electronic apparatus is provided that: source is harmless. designed so as to be relatively unaffected • it is used for the purposes of • In consideration of others in the by electromagnetic disturbance from experimentation, learning or practical school, the laboratory RF transmitter external sources, it is not immune from training; and should not be left switched on for a gross disturbances. Any laboratory RF • it is used within a school classroom or prolonged period. The signal strength transmitter could cause neighbouring laboratory. transmitted is not great: at 3 m it is computer and other IT and telecoms Regarding EM disturbance caused by a roughly equivalent to signal strengths systems to crash, with the potential for laboratory source, we recommend the from broadcast radio stations. major risk of harm to the health and Laser equipment offer Five laser diode modules and photometers from the Physics Department of Heriot Watt University are on offer for long-term loan to schools. This equipment has been specially design- interest, contact the Centre by the end of operating current is also adjustable, ed for schools by Heriot Watt University January 2003. allowing the threshold of lasing to be determined. Light intensity is measured and is available, through SSERC, for The laser diodes are Class 2, emitting with a large area photodiode. With lots of extended loan. The first lending period 640 nm radiation at a radiant power of parameters to adjust and measure, there is will run from now until June 2004. Future about 0.4 mW. The diode temperature is ample scope for an Advanced Higher, or periods will run for one session. Schools controlled by a Peltier effect device and even Standard Grade, Investigation. will be selected by ballot. To declare an may be set to between 8 ºC and 40 ºC. The SSERC Bulletin 207 Winter 2002 207 - 11 Trade review Portable radiation detectors This trade review tells you what’s on the market and the sorts of radiation hotspots to search for in your school environment. Are portable radiation detectors worth having? That’s for you to judge.

If the intention is to measure the count Stupplier Produc Oerder code Psric Note rate from environmental sources, then the name main natural sources are 238U, 232Th, 222Rn, 210Po, 210Pb and 40K. Generally you would be looking for a hotspot whose activity Arscol Geige P273-1350 £K267.5 Spec seems O was less than background – a tall order Counter and with a primitive instrument and short Ratemeter sampling period. Crarolina Geige B3A-75-9470 £K29 Spec seems O • Probably your best, low activity, natural Counter except that dose rate source would be a potassium salt such units are mR/hr as KCl, or the common food additive, LoSalt. A teaspoonful of either can F,rederiksen Ratemeter 54135.55 £e22 Rather insensitiv provide you with a count rate that is Analog Electrical output can perceptibly greater than background. be counted by a PASCO interface • The concentration of radon varies considerably from place to place and Hearris Radioactiv B05A00681 £r18 Too insensitive fo time to time. It is generally lower Count Rate very low activity outdoors than indoors. The SensorMeter sources. concentration can be greater in a See Bulletin 194 poorly ventilated basement than elsewhere in a building. The outdoor, PaASCO Bet S0N-7928 £s23 Count detection i ground level concentration can Gamma primitive when used increase during the stillness of the Nuclear as stand-alone night caused by the formation of a Sensor instrument. Can be cold, dense blanket of air trapping used with PASCO radon near to the surface. This layer is interface. destroyed by daytime breezes or Scientific & Ratemeter, XAR 050 £y225 Supplied b winds because of the vertical mixing Chemical Analogue 010 Frederiksen, as above of the air these effects generate. Concentrations tend to increase with a SEP Geiger G8EI 003 £,12 Counts reset by hand fall in atmospheric pressure. Typically (Middlesex Counter counting non- any of these effects can change the University) automatic. background count rate by a factor of LCD display. between 0.7 and 3. Urnilab G8eigertelle E05C5100 £.282.2 Primitive indicator • Extracting air through a filter can build Electrical output to up a concentration of mainly Po-210 dataloggers. on the filter, causing the background count rate next to the filter to double. Vnernier Radiatio R4M-BTD £s21 From photograph, thi Depending on the efficiency of the Monitor product resembles the detector, a typical count rate from one from Carolina. background radiation usually lies Stand-alone between 10 and 30 counts per minute. instrument, or can be Thus a suitable range for a portable used with Texas CBL2 radiation detector to be used to hunt for datalogger, Vernier environmental hotspots might be 0-100 datalogger and counts per minute. probably dataloggers from DJB and Of the instruments listed (Table 1), the PASCO. Harris SensorMeter has been tested by us and is quite unsuitable for studies of very Table 1 Trade review of portable radiation detectors. low activity sources because of its short Counter is switched by hand, it is able to counting periods (Bulletin 194). The three production from the Government’s detect very low-level radiation by letting it that would seem to be most suitable are Science Enhancement Programme (SEP). It count for a very long period. It can the ones from Ascol, SEP and Vernier. is on sale through Middlesex University therefore be used for environmental None of the three has been tested by but currently SEP are offering some monitoring. SSERC. The SEP Geiger Counter is a new Counters free to schools. Since the SEP

207 - 12 SSERC Bulletin 207 Winter 2002 Trade review New ICT packages

Simple Data Handling This new software from DJB Microtech has been produced for the 5-14 market to allow data to be presented in a variety of formats, namely: pie chart, bar chart, line graph or histogram. Having selected the format, the pictorial presentation appears and builds up as data is keyed in. The features are minimalist, befitting the intended age-range. It produces simple charts and graphs in brilliant colours, but doesn’t provide any analytical tools, because that is seen as being an unwant- ed complication. Tables and charts can be copied and pasted to other packages. Data can be saved either as an SDH or Alba file; the latter route allowing data to be analysed with Alba software. Alternatively, Alba files can be transferred to SDH - for instance, to utilize the histogram facility (Fig. 1). The program runs on Windows 98 or above, costs £35 for a single user, or £100 for a site licence. LogIT products Figure 1 Explorer Controller Simple Data Handling histogram (DJB) showing the distribution of radioactive count per minute from a few grammes of a potassium salt. The label ‘Count’ (LH axis) is the number The Explorer Controller set (curricular of samples in the histogram bins and is not to be confused with radioactive count rate. relevance: 5-14) is a new accessory for the The program lets you relabel the title, but not the histogram axes. LogIT Explorer providing computer • Upgrades from previous versions of control of motors, lamps etc. The PASCO products Insight are available at 30% discount - controller plugs into an Explorer with a please note upgrades are only PASPort Xplorer jack lead. Simple sequential or feedback available direct from DCP with proof This small, hand-held instrument logs data control can be achieved using the of purchase, or a copy of the original without initial recourse to a computer. standard LogIT Lab or Insight software, licence. Only once your measurements have been which is supplied with the Explorer. The taken need you plug into a computer via controller board is battery powered and • A Macintosh version will be available a USB port and download your data for can operate 3 V to 4.5 V devices. The set from early 2003. display and analysis, either at a simple includes a motor, fan blade, bulb, bulb Packs purchased via DCP also include an level with EZscreen software (supplied holder, buzzer and a pair of crocodile clip Insight 3 CD free of charge, which will with Xplorer), or DataStudio (extra leads. Also included is a guide with work with both Apple Mac and Windows purchase). The Xplorer is operated by a suggestions for several investigations. computers. set of 6 button switches, with cues on a 2- The set costs £49.99 (DCP reference line LCD display. One Xplorer on its own number D 105150). Junior Datalogging costs £199 (14-1244); if bundled with a DataLogging Insight 4 Coming soon - Junior Datalogging Insight, group of sensors, prices start at £405. with features such as animated characters. Logotron have released Version 4 in the DataStudio Insight software family. New features DataMeter USB Windows Starter To make full use of Xplorer, you would include comprehensive formula and Pack also need the program DataStudio. The maths modelling facilities, and Insight latest release is Version 1.7.2. Existing Laboratory. This has interactive tutorials This all-in-one starter pack for Windows is users can upgrade at no cost by down- with photographs of the equipment, step- supplied with a USB cable instead of a loading from the PASCO website. For new by-step instructions and other enhance- serial port cable. The pack contains users, the cost is £122 for a single user ments such as multiple tiled windows and DataMeter 1000, a mains adapter/charger, (14-1196), £429 for a site licence (14-1197), automatic sampling rates. light and temperature sensors, LogIT Lab software for Windows, USB link cable and or £467 for home use also (14-1195). • Available for Windows 98 or above, manuals, all packed inside a carrying case. USB/Serial Converter single user software costs £85 with 5- A pack costs £310 (DCP reference number 100 user licences also available (single D 100332) This (CI-6759, £110) lets you run a 300, 500 user pack DCP reference number or 750 ScienceWorkshop interface D100550). through a USB computer port. SSERC Bulletin 207 Winter 2002 207 - 13 Biology Botanical and ecological fieldwork - new Floras The several new Floras that have recently been published provide invaluable aids to fieldwork.

This note mentions a number of recently The Changing Flora of published resources that will be of interest Glasgow, Urban and Rural to teachers of Geography and History as Plants throughout the well as of Biology. These resources pro- Centuries, Dickson et al., 2000, vide, in addition to the Flora listings, many (ISBN 0 7486 1397 8), Edinburgh coloured plates and a wealth of very read- University Press, 402pp, price able background information on topics £30, HB. The plant distribution such as the influence of geology, climate maps in this book are based and the activities of humans on the distri- on a 15 year survey carried out bution of plants. These new publications by The Glasgow Natural are valuable tools which can be used by History Society. Available from schools in studies of ecology, land use and bookshops and from related topics. Summerfield Books. Figure 1 Distribution of Hogweed in the Lothians (Smith P.M. et al.). A major work, the “Atlas” covers the British Plant Life of Edinburgh and Isles: the Lothians, Smith, P.M. et al., 2002, Edinburgh University The New Atlas of the British and Irish Flora, Press, (ISBN 0 7486 1336 6), Preston, C.D. et al., 2002, (ISBN 0 19 851067 416pp, price £25, HB. The plant 5), Oxford University Press, website: distribution maps in this book www.oup.com. The Atlas contains 912 are based on a 20 year survey pages and 2412 colour maps, price £99.95, carried out by the Botanical HB. Supplied with the book is a CD-ROM Society of Scotland (formerly that enables users to view and print out the Botanical Society of Edin- distribution maps and add on overlays burgh). A CD-ROM containing containing environmental information. habitat and frequency data Recently published local Floras include: and maps showing the distri- Figure 2 Distribution of Giant Hogweed in the Lothians Flora of Assynt, Evans, P.A. and I.M., and bution of all the species (Smith P.M. et al.). Rothero, G.P., 2002. Those of you who go recorded in the survey is walking and climbing among the Lewisian currently being prepared. Requests for Flora of the Outer Hebrides, Pankhurst, J.R. gneiss, Torridonian sandstone or copies of the CD-ROM should be sent to and Mullin, J.M. (Reprinted 2001), 185 pp, Cambrian quartzite of the area can have the Secretary of the Botanical Society of price £30, (Paperback) from Summerfield your days enriched. Names of plants are Scotland. A small fee will be charged. Books. in Gaelic in addition to the usual Latin and Marketing arrangements for the book are Flora of North Aberdeenshire, Welch, D., English. Containing over 300 pages it is not yet finalised, but presumably will be (1993), published by author, 184pp, price available from Summerfield Books at the same as those for the book on the £21, from Summerfield Books. £17.50. Flora of Glasgow. Local Floras for many other areas of Scotland including Iona, Arran, Fife, Shetland and Perthshire have been published. These can be found in the list of the Botanical Society of the British Isles (BSBI) publications sold by Summerfield Books, or possibly from local libraries and bookshops. One of the ways in which the plant distribution maps in Plant Life of Edinburgh and the Lothians can be used is illustrated in the following example: Hogweed (Heracleum sphondylium) is a native Figure 3 Giant Hogweed (Heracleum mantegazzianum), photographed at Sheriffhall, Midlothian, spreads by plant. The map (Fig. 1) windblown and waterborne seed along roads, railways and rivers. C. E. Jeffree.

207 - 14 SSERC Bulletin 207 Winter 2002 Biology / Phenomenology shows that it has a widespread a non-native plant, i.e. an alien or these attempts are not being successful distribution in lowland areas and the introduced plant. Contact with the sap of and that Giant Hogweed (Fig. 3) is well habitat data indicates that it is commonly this plant can cause skin irritation and established in some parts of the Lothians, found on roadsides. In contrast, Giant attempts are made to destroy the plants. particularly along river valleys. Hogweed (Heracleum mantegazzianum) is The distribution map (Fig. 2) shows that Phenomenology An example of the science of phenomena with Chladni’s plate. Malin Starrett did not have a normal of St George. More complex patterns and sense vibrations in the air above anti- science education. Although getting A higher order resonances can be created nodal zones, but fail to sense vibrations Levels in science and electronics, he went with other bowing positions and finger above nodes. If an empty 330 ml bottle is off to art college, where he got his first restraints. In all, a set of 12 patterns can be inverted with its open end 1 cm above the degree. After that, having a burning desire produced. Once the first 2 or 3 patterns plate, air in the bottle can be heard to to study science, he returned to art college have been shown, most observers can resonate long after the plate itself has 3 years later to work for a doctorate in the work out the rules and find fresh patterns ceased to ring audibly. The lesson can subject. This allowed him to study what (Fig 1). lead on to effects with other related apparatus, such as resonances in a he wanted. He is thus largely a self-taught What might pupils get out of this? First stretched elastic with mechanical scientist. and foremost, they would probably be oscillator2. I give you this background because when amazed and marvel at these phenomenal you hear that someone with such an sand patterns. The lines are so finely But rather than stray into the science of unusual training has applied his mind to uniform, they appear to have been drawn sound, musical instruments, oscillations, or how science might be taught, you expect with a machine tool. Secondly, they would waves, let’s return to the phenomenon a fresh approach. As it turns out, you will get a thrill out of witnessing events that with a fresh eye. What do we see? A not be disappointed. sprinkling of sand scattered at random over a flat plate. What One of Malin’s present interests do we do next? We apply some is Chladni’s plate1 . Although a energy to the system by bow- standard piece of apparatus, it is ing the edge of the plate. We not, I believe, much used apply a white noise source3, with nowadays. Indeed I do not ever its jumble of assorted recall handling an enquiry on it frequencies, and this causes the in my 20 years at SSERC. But let grains of sand to jump about me describe why Malin thinks and form these remarkable this apparatus is significant. patterns. Where else do we get Chladni’s plate in its simple form patterns? Look around at consists of a square metal plate nature: the morphology of a with sides about 13 cm long snow flake, the regular geometry supported quite tightly in its of a crystal, the structure of a leaf, centre. When lightly dusted with the branching of a tree, the sand if an edge of the plate is architecture of DNA. How did bowed with one strong stroke of these shapes all form? Matter is a violin bow, the plate can particulate: apply an energy Figure 1 resonate, emitting a strong The Argyll pattern on Chladni’s plate. source; the particles move at ringing tone. The vibrating sand random: resulting from their settles to form striations running along would be totally unexpected and random jiggling, they can sort themselves nodal lines in the plate. The resulting reproducing the effects for themselves. out into clusters to form larger objects pattern depends on where the plate had And thirdly, they would quickly see how to such as rock crystals, fluffy clouds, or DNA. been bowed and where else it had been render different patterns and ringing Attracted by the weird wails from Chladni’s held with a finger. With correct tones because the rules can be worked plate, 2 colleagues came along to see what positioning, a nodal line runs from where out by thought, and trial and error. It is was happening and, as a matter of record, the edge had been touched with a finger really a lesson on phenomenology, where spent the rest of the day watching, trying, while an anti-nodal zone extends from the aim is to study the science of being amazed and discoursing. Some- where the bowing took place. phenomena. With some classes, that might be quite sufficient. times science is phenomenal. Here is just Bowing the mid point of an edge and such an example. Where else might the lesson lead? gripping one corner produces a St 2 Inferences can be drawn from watching Chladni’s own research began with 1- Andrew’s Cross pattern. By alternating dimensional vibrating systems. the movement of the grains of sand. On these positions, you end up with a Cross 3 nodal lines, the grains are stationary. The bow seems to act as a white noise source for the first instant only of bowing. 1 Malin Starrett can supply a basic kit of 2 Elesewhere they jump and a few can be Thereafter it starts to match the resonant square plates, stand, 105 page manual and seen to oscillate. If a finger is held 1 cm frequency of the system, building up the other items, but without bow, for £170. above the plate, nerves in the fingertip can amplitude of vibrations. SSERC Bulletin 207 Winter 2002 207 - 15 News

Trade news White phosphorus Addresses Chladni’s plates Despite many enquiries, we have failed to ASE Booksales, College Lane, Hatfield, find a source of supply of white Hertfordshire, AL10 9AA. T: 01707 283000, Malin Starrett (storyline overleaf) has 3 F: 01707 266532, W: www.ase.org.uk phosphorus. It would seem to be versions of his Chladni’s plate kit costing unavailable in the quantities required by Ascol, PO Box 6745, Beeston, Nottingham, between £170 and £230. These kits all schools. NG9 6QN. Tel: 0115 925 6049, depend on using a violin bow to cause F: 0115 925 4511, E: [email protected] the plate to resonate. Two other Leybold Didactic Botanical Society of Scotland, c/o Royal Botanic manufacturers, Frederiksen and PASCO, Garden, Inverleith Row, Edinburgh, EH3 5LR. This leading designer and maker of produce plates that fit on vibration Carolina - see Instruments Direct generators; with these, the plates are physics apparatus have reopened a UK Comcal Scotland Ltd., 11 Bath Street, Glasgow, brought into resonance by adjusting the sales office. Please contact the company to obtain a catalogue. G2 1HY. T: 0141 332 8527, F: 0141 332 8527, oscillator frequency to match one of the E: [email protected] plate’s natural modes of vibration. The DCP Microdevelopments Limited, Bryon Court, effect with an oscillator is probably less Bow Street, Great Ellingham, Norfolk, NR17 1JB. phenomenal than with a bow, but may be T: 01953 457800, F: 01953 457888, simpler to explain. E: [email protected] Frederiksen Resonance Plate, Square 2185.20 £6 Didactic Systems Ltd. (Jennie Oakley), Frederiksen Resonance Plate, Round 2185.25 £9 Coombe Lodge, Blagdon, BS40 7RG. T: 01761 463659, F: 01761 463641, PASCO Chladni Plates Kit WA-9607 £87 E: [email protected] Harris and Unilab repairs djb microtech, Delfie House, 1 Delfie Drive, In the last issue we directed you to contact Greenock, PA16 9EN. T/F: 01475 786540, Techlab for the repair of electronic boards, W: www.djb.co.uk such as Alpha. We are sorry to say that Experience of Experimenting (Malin Starrett), this is incorrect. If you have any Harris or Unit A28, Valley Business Centre, 67 Church Road, Newtownabbey, Co. Antrim, Unilab equipment that needs repairing, BT36 7LS. T: 028 90552721 whether Alpha kit or anything else, please contact the Harris repair number listed Frederiksen - see Nicholl Education. opposite. Griffin & George, Bishop Meadow Road, Loughborough, Leicestershire, LE11 5RG. Middlesex University T: 01509 233344, F: 01509 231893, E: [email protected] The Teaching Resources catalogue from Philip Harris Education: Middlesex University features many E6 North Caldeen Road, Calder Street, things of interest to teachers of Science or Coatbridge, Lanarkshire, ML5 4EF. Technology, including these smart T: 01236 437716, F: 01236 435183. materials: Findel House, Excelsior Road, Ashby Business Brass shim (TS6 005) £2.23 - for making switch contacts Bloody Cranesbill (Geranium sanguineum) an Park, Ashby-de-la-Zouch, Leicestershire, Smart wire (PAC SW1) £5.01 - a shape memory alloy whose example of coastal flora at Aberlady Bay; from LE65 1NG. T (sales): 0845 120 4520, the Plant Life of Edinburgh and the Lothians, T (repairs): 01530 418111, F: 01530 419 492, length changes when it conducts current one of the new Flora described on Page 14 W: www.philipharris.co.uk/education Smart springs (PAC SW3) £1.78 - provides a useful pulling (Photograph by C. E. Jeffree). HSE Books, PO Box 1999, Sudbury, Suffolk, force when acted on by current CO10 2WA. T: 01787 881165, F: 01787 313995, Thermocolour sheet (IT9 001) £2.23 - temperature W: www.hsebooks.co.uk PASCO - see Instruments Direct indication Institute of Biology (Scottish Branch) - Revolution Education Ltd, 4 Old Dairy Business Peter Anderson, Fife Council, Auchterderran Polymorph (PL1 004) £8.90 - a new polymer for use in Centre, Melcombe Road, Bath, BA2 3LR. Centre, Woodend Road, Cardenden, Fife, model making or prototyping T: 01225 340563; F: 01225 340564 KY5 0NE. T: 01592 414676, F: 01592 414641, Smart images (SM1 004) £5.20 - thin film with E: [email protected] E: [email protected] holographic images Scientific and Chemical, Carlton House, Instruments Direct Limited, Unit 14, Livingstone Road, Bilston, West Midlands, Smart grease (SM1 003) £1.39 - for making a constant Worton Road, Isleworth, Middlesex, TW7 6ER. WV14 0QZ. T: 01902 402402; F: 01902 402343; torque motor T: 0208 560 5678, F: 0208 232 8669, W: www.scichem.co.uk W: www.InstrumentsDirect.co.uk/pasco and apparatus: Science Enhancement Programme (SEP), Leybold - see Didactic Systems Allington House (1st Floor), 150 Victoria Street, Motor Kit (MOT 001) £10.91 - self assembly dc motor Middlesex University, Teaching Resources Ltd., London, SW1E 5AE. T: 020 7410 7129, Unit 10, The 10 Centre, Lea Road, Energy Exchange (SEP 004) £67.50 - energy conversion F: 020 7410 0332, E: [email protected] Waltham Cross, Herts, EN9 1AS. demonstrations Summerfield Books, Main Street, Brough, T: 01992 716052, F: 01992 719474, Microcentrifuge (CEN 006) £60 - up to 13,000 rpm off Cumbria, CA17 4AX. T: 017683 41577; W: www.mutr.co.uk E: [email protected] 12 V Nicholl Education Limited, 4 Westleigh Hall, Engineered Bioreactor (BIO 001) £58.24 - scaled down Unilab - see Philip Harris Wakefield Road, Denby Dale, Huddersfield, version of an industrial process Vernier - see Comcal Scotland Ltd. HD8 8QJ. T: 01484 865994, F: 01484 860008, E: [email protected]

207 - 16 SSERC Bulletin 207 Winter 2002 SSERC Bulletin 207 Winter 2002 207 - 17