SCOTTISH SCHOOLS SCIENCE
EQUIPMENT RESEARCH CENTRE
Bulletin No 139 February 1984
cover) on back (Continued
582262). 0908 (Tel
8DT.
MK17 Bucks.. Guise, Aspley Hill, West House, Radlett Ltd., Instruments Metragram
DE142LA. Staffs., Burton-on-Trent, Street, Derby 5 Computing, Mercian
0333). (Tel. 061-624
6LF. OL9 Lancs., Oldham, Street, Neville (Locktronics), Ltd., Co. and Lock M. A.
-802 5144). 01 5JB.
(Tel. N15 London Road, Roslyn Works, Roslyn Ltd., Co. Manufacturing Linstead
5555). 097-883 (Tef.
OTU. LL12 Wrexham. Estate, Industrial Llay Road, Aerial Ltd., Electronics Limrose
076347191). (Tel. SG85HE. Herts., Royston, Road, Orchard Ltd., Chemicals Matthey Johnson
01-6866441). (Tel. CR94QL. Surrey, Croydon, Way, Purley 294 Ltd., Irwin-Desman
0X2 9AT. Oxford,
Hinksey, North
College, Westminster (ISMEC), Centre Microelectronics Schools Independent
041-3326088). G4. (Tel. Glasgow Road, Garscube Estate, Industrial Oakbank Scientific, l.M.S.
022166110). (Tel. Wilts. Road, Bradford-on-Avon, Trowbridge 87A Education, for Ideas
Road,London,NW62BP.(Tel.01-3281551). A.R.HorwellLtd.,2Grangeway,KilburnHigh
34983/4). 03552 (Tel. Kilbride. East Centre, Town House, Strathmore 34-36 Ltd., Harris Philip
413063). (Tel. 0934 9BJ. BS24 Avon, Weston-super-Mare, Oldmixon, Ltd., Biological Harris Philip
5680). 041-248 M239NP. (Tel. Manchester, Wythenshawe, Road, Ledson Ltd., George and Griffin
72071). 09062 (Tel.
lAS. BN16 Sussex, West Preston, East Road, House, Worthing Gerrard Centre, Gerrard Biological
61365/6). 0843 (Tel. Kent. Broadstairs, Road, Margate Works, Exelo Sons), and F. Flaig (W. Exelo
0582602688). (Tel. LU55PE. Beds., Dunstable, Avenue, Buckwood 28 Edu-Elequip.
373666). 0525 (Tel. 8RX. LU7 Beds., Buzzard, Leighton Street, 30 Lake Electronics, Educational
0737 62787/8).
(Tel. Surrey. Redhill, Holmethorpe, Avenue, Ltd., Holmethorpe Plastics Scientific and Educational
0494774481). (Tel. Bucks. Chesham, Road, Sunnyside House, Draeger Ltd.. Safety Draeger
51496). UB83PH.(Tel.0895 Uxbridge, University, Brunel Service, Science School CLEAPSE
3131). 031-225 (Tel. Edinburgh. Street, Queen 5 Broadcasting, for Council Schools BBC
0707267411). (Tel. AL1O9AA. Herts., Hatfield, Lane, College Education, Science Association for
025482415). (Tel. PR33XU. Lancs., Preston, Ribchester, House, Salewheel (I Ltd., forE) Artec
1037). 031-557 2184cr 031-556 3RZ. (Tel. EH1 Edinburgh, Street, Broughton SSSERC, 103
LIST ADDRESS Introduction Key for CLEAPSE
ASE Annual Meetings The “key of the door” we mean. Our sister organi sation furth of the border having just come of age. We It is hard to believe it’s again that time of year when congratulate CLEAPSE School Science Service on some SSSERC staff have just struggled back over the entering their 21st year in the equipment evaluation border from the ASE parent body meeting. Now we and consultancy ‘business.’ With some, mostly minor, begin thinking about the Scottish Region gathering differences their aims, functions and organisation are over Easter. I must begetting old! similar to those of SSSERC. We would record here our appreciation of the co-operation of CLEAPSE staff in much that both organisations have been involved over As usual a fair amount of this, the first issue of the two interesting decades of activity. New Year, is taken up with ‘Trade News’ garnered at the U.K. ASE meeting in deepest England. Happy Birthday, CLEAPSE’
The flavour of the Exeter meeting could be sum Micros in Schools Scheme marised as development and consolidation of the issues and themes described in our report of last year’s We have been asked to clarify certain ambiguities in proceedings (bulletin 134). For example, the number of early Department of Trade and Industry documentation kits available for illustrating some principles of for the “Extension Scheme.” The BBC ‘Buggy’ and/or biotechnology has increased together with the range of VELA are available as optional “pound for pound” hard and software, from both manufacturers and items whether or not schools want the basic computer pubtishers, for interfacing applications. extension package. In addition “schools that did not have any equipment under the original offer may now be considered.” Education/industry liaison arrangements continue in their latest healthy resurgence. A number of well known, larger industrial concerns were present, continuing to reach out to the world of education, offering help at varying levels. Not only is much assistance available in the more usual forms such as Cost index resource packs, kits, games, films and posters, new areas are being explored. Assistance is now offered Our cost index for consumable items is sampled twice with the development of management skills, both in yearly, in May and again in November. The ‘100’ general and within the specific context of school baseline was set in May 1974. In November, 1983 it science departments. stood at 318.64. Calculation of the percentage increase since November l982givesan annual figureof Ca. 2.7%. The six-monthly figure to November 1983 is approxi Another welcome development is the continuing mately 0.7%. We must-stress that these figures are efforts made by many manufacturers to keep prices relevant only to consumable items such as glassware, down. Cost cutting design changes allowing more chemicals, biological specimens, resistors, drycells etc. efficient production were again in evidence. Several pieces of equipment had been completely redesigned in an attempt to reduce prices but hopefully avoiding The shopping basket, upon which the index is based, significant reductions in quality. It may be cruel (and does not include capital items. We thus advise caution grossly unfair) but I am unable to resist drawing the in use of the index for such items because we are fairly obvious parallel with early Marks and Spencer philo sure that its slower growth, compared with that of the sophy. The favourite cartoon of a certain M and S more general retail price index, has been partly caused Chairman was said to depict a boardroom meeting, in by recent intense competition among suppliers in the the background a wall chart showing a plummeting consumables market. At present we have no equivalent sales graph, in the foreground the board chairmn data for capital items and cannot say whether or not saying: competition has produced a similar check on price increases. ‘I move that we begin offering a range of quality goods at competitive prices—after all, we’ve tried everything else.’ CLEAPSE Guides The Scottish Region Annual Meeting is to be held in CLEAPSE School Science Service staff haven’t let Moray House College of Education. It will run over only 21st birthday celebrations prevent them minding the two days this year—the 11th and 12th of April, inclu shop. We have recently received the following new or sive. We will be there, with ‘Foundation Science revised guides from our sister organisation. Copies of apparatus, general d-i-y equipment, microelectronics these publications can be borrowed for up to one month and interfacing displays. Why don’t you join us? by application to the Director of SSSERC. L19B2 “Data Stores and Chart Recorders” The of corrosion and if necessary be disposed of. If the valve final part of the guide “Automatic Graphs” (Parts is still working after a fashion, disposal is by allowing a A and Bi are also available). This new part is slow leak into the atmosphere from a fume cupboard. primarily an evaluation of Data Stores and Chart Alternatively it can be absorbed into flowing water Recorders but VELA and GIPSI are also discussed using the device shown. as possible alternatives to a data store.
L132 “Solar Panels” Part A introduces solar energy collection and suggests how solar panels can be used in teaching. Appendices give data, theory, d-i-y tips, books and addresses. Part B evaluates panels from educational suppliers.
L170 “Progammable Laboratory Instruments” A guide to VELA and GiPSI with a discussion of waste the place of modern instruments in school science teaching.
Fig. 1 Safety Notes Electrical Safety In the event of a valve jammed open the gas can either be allowed to leak away or be absorbed in water HSE Guidance using the same apparatus, but with the faulty syphon in a polythene bag fitted with a bung carrying a tube. The Health and Safety Executive have recently published a “Guidance Note GS23—Electrical Safety We have always recommended that each suite of in Schools” HMSO 50p, ISBN 011 883567 X. This is a laboratories and stores should have available as part short outline policy guide but does contain some useful of a spillage/disposal kit a small cheap cartridge detail for the science teacher. It is obtainable from respirator to enable a teacher or technician to enter a branches of HMSO and further information or advice is room to open windows and carry out the initial ‘first available from Area Offices of the HSE. aid.’ These are available from several firms, eg. the (See also ‘Trade News” “Electrical Safety” section). Parat(II) from Draeger Safety costs £15.00. BDH lecture bottle cylinders are only accepted back Syphons and cylinders if in prime condition. Recently there have been some cases of these which had been neglected, left in the An Edinburgh school has reported to us an unusual back of fume cupboards with the result that the valves accident concerning a sulphur dioxide syphon of the had seized up. usual size (500g). Corrosion of the valve or screw fittings where the valve cap contacts the aluminium cylinder is The disposal of cylinders of hydrogen sulphide and well known. The remedy is to store the syphon on an chlorine was clearly a specialist task. Whilst the cost open shelf and not with the other smelly volatile of disposal of a cylinder was reasonable at £16, the cost corrosives eg. phosphorus pentachloride, ethanoyl of a special collection vehicle from Scotland to Harwell chloride, bromine etc. was £300! This problem occurred in an F.E. College.
The difference in this case is that a small pin hole The message is to ensure a quick turn over and to developed in the side of the cylinder approximately one store such cylinders and syphons in a well ventilated third of the way up from the base, and just at the point and non-corrosive atmosphere. where the end of a right-angled glass delivery tube left attached was making contact. It was probably due to a Bell jars—the saga continues slow leak of sulphur dioxide, now dampened by contact with air, attacking the point of contact. The inside of the After yet another report of an implosion of an eva syphon is in contact with sulphur dioxide, but there it cuated bell-jar we would draw the attention of teachers is dry. to our advice, previously published in Bulletin 132. ‘This incident should serve as a timely reminder of The room was found full of sulphur dioxide and a the forseeable risk of an implosion whenever such teacher was exposed to the gas whilst removing and vessels are evacuated. In such demonstrations eye disposing of the cylinder. We now recommend that protection should be worn by the demonstrator. Two protect the delivery tubes are not left attached to sulphur dioxide safety screens should be employed, one to the pupils!’ syphons in storage. Syphons, especially if more than teacher and a second one to protect two or three years old, should be examined for signs
2 Foundation Science Notes right through to total reliance on locally produced, moderated packages is theoretically possible. Foundation Checklists We have no quarrel with this prospect. We welcome it and the broadly limited freedom of action it offers. At the suggestion of SSSERC Planning Committee We welcome also the prospect of sensible growth and members we outline below a framework for decision change. Changes in science and techiology are taking making, designing and documenting equipment needs place rapidly and continually. Syllabuses fossilised in for “Standard Grade” implementation. the amber of past examination papers make less and less sense. Background Unfortunately, there is no such thing as a free Very shortly after publication of the Munn/Dunning lunch’’. Just as internal assessment, the assessment of reports we raised, in these pages (Bulletin 102, Feb practical skills and the use of extended grade related ruary, 1978), issues connected with equipment. Our criteria cause administrative problems for others, a basic arguments haven’t changed over the intervening modular syllabus with local variants gives SSSERC fiveyears. The central theme is that equipment provision certain headaches. should not be an afterthought, but an important consideration throughout the development of any new Equipment Lists course. Nor should experiments or apparatus become fossilised once the course is finally adopted. Science is At present we have no plans to respond to pleas for a technologically organic activity and school courses definitive equipment lists for Foundation Science. We should reflect this growth and development. can give three reasons:
Patterns of Development —because of the modular nature of the course it would be hard to draw up a single list relevant Over the previous two decades, a pattern of curri to all variations which may exist. culum development in science has evolved in which certain assumptions about equipment and resources have prevailed. The pattern very often has been: —the existence of an official’ equipment list implies the prior existence of ‘official’ experi ments, suggested practical activities etc. Fossil —to identify content — objectives —write a syllabus isation is something a modular syllabus is —prepare materials supposed to helo us avoid. —identify the equipmentlresources required and prepare teachers’ guides, equipment lists etc. —we were involved during the production of nearly all of the REFER examplar materials. This pattern has led to the assumption that the mere We tried to ensure that sufficient, relevant existence of a new syllabus is in itself an unassailable detail was given on equipment and safety within justification for full resource provision; and that such the materials themselves. Where it was missing a development can be used to lever financial support from Education Authorities. we suggested its addition to the author(s). This advice was usually heeded. Where large gaps Times have changed. Such a pattern of development existed, such as the need for a complete piece of is no longer viable. The present financial context alone apparatus, yet undeveloped, we have responded argues strongly for a broader view. That financial to that need in this Bulletin. context, hopefully, may change. Indeed there are equally powerful arguments, if and when the economic So for the moment, no ‘quasi-official’ equipment situation eases, for heavy capital investment to replace lists from us and hopefully not from others. However the tired, worn-out and obsolete science teaching we are open to persuasion for the national examplers. equipment presently in many schools. There are The workload involved in catering directly for locally alternative, more lasting, educational reasons which produced materials doesn’t bear contemplation. support our plea for a broader view and a more sophis ticated approach to equipment provision. Critical frameworks
The nature of the current course in Science makes for SSSERC has long argued for examination of equip difficulties in drawing up any definitive equipment ment. resource and safety implications at the early lists. Examplars for the 4 Core topics and several writing stages of any curriculum development. options are being distributed through the REFER system. However, as we understand it, there is no In fairness to those involved in current activities it compunction to base a response to the guidelines on has to be acknowledged that an attempt has been made a wholesale adoption of examplar material. Indeed local to keep new equipment demands to a minimum. It may variants abound. A complete spectrum of response be that the economic rather than the educational
3 L arguments (both already made here) have been to the (b) Costs fore. Related directly to (a). An expensive piece of We would argue that if frameworks can be provided apparatus far one-off demonstrations may be for moderation of course content and assessment, then acceptable shared across other pupil groups why not a framework or checklist to guide equipment through judicious timetabling. On a pupil experi and safety decisions? If some central body cannot assist ment scale, provision may be impractical. directly in shredding all topics from the technical hardware and safety viewpoint, why not provide the Checkpoints means for self-help? In the SSSERC methodology, financial aspects form only one of a number of important —is the required apparatus too costly at the considerations. scale of provision envisaged? —can less expensive alternative equipment be Checklists found by substitution?d-i-y? —can the scale of provision be reduced by In developing and writing local courses for the use of alternative teaching/management strategies? a single teacher, department or school, one can afford to be idiosyncratic in selecting equipment. It is in (c) Availability transferring written materials that problems arise. Such transfer can save much duplication of develop Individual schools often have particular pieces or ment effort. Further needless work can be avoided by a models of equipment which are obsolete or not little thought, some extra writing and a proper attention widely held by others. D-i-y designs may make use to detail. of scrap components which just happen to be at hand. This is fine for that school but bad news to a technician or teacher elsewhere trying to equip a Criteria in selecting / designing equipment for course? course. topic Checkpoints Best summarised by the phrase ‘Appropriate Technology.” —is the equipment specified commonly held or freely available? Equipment has to be appropriate as to: —is it necessary to specify so closely eg. a “Jock McDermott’s Model B pupil grinder” —teaching methods/learning conditions or can a range of acceptable common items —costs be given? —availability —if this is a d-i-y design are all the components —storage limitations available to the majority of schools? —safety —and, for d-i-y apparatus, constructional diffi (d) Storage limitations culty. Related to (a). Large items and demonstration Of course, these issues are inter-related and inter equipment may be used infrequently but take up a active. For ease of description only we will take each in lot of space. turn. Checkpoints (a) Teaching methods? learning conditions If there are likely storage problems: Equipment useful for resource based, pupil paced activities may not be ideally suited for teacher —could the scale be reduced without producing centred methods. other problems? —can the equipment be made ‘Knock-down’? Checkpoints —can the one item be made to perform several tasks? Is the suggested activity: (e) Safety —resource based/individualised? —a demonstration? This is also related to experimental design. The —pupil experiment, teacher led? current prevalence of taking the easy way out by —a group activity? abandoning an activity seen as potentially hazard —a station? (in a circus?) ous should cause all concern.
Dotheset-up and equipment match the application? Teacher and technician response is often far too
4 digital, too all or none. Safety is an analogue available to others, documentation should phenomenon, a continuum. be to high Questions of accept professional standards. The omission ability or otherwise of a practical of one tiny but activity require relevant detail, such as a part or catalogue considered judgements, not snap decisions. number, can waste a great deal of a lot of peoples’ time. Checkpoints SSSERC is always interested in receiving novel ideas If the activity involves a hazardous process or and cfesigns for equipment. This is particularly so at chemical: present with all that is happening on the “Science” front. There is never a final word in equipment design. —can the hazard be isolated, contained or We believe that equipment innovation is one sign of a removed? healthy science department. Doing science is just as eg. if the hazard is physical/electrical provide important as writing courses on it, or the current extra protection/insulation, etc. obsession—assessing the learninq of it. if the hazard is chemical, wear protection, or use in a closed’ vessel, contain in a In an attempt to assist those writing up and drawing fume cupboard etc. equipment, either for use by other local schools or for —can the scale be reduced? wider publication in our Bulletin, we give below a eg. work at lower voltages, with smaller documentation checklist: quantities at lower concentrations, using better means of containment of Checkpoints for d-i-y documentation chemicals etc. —is substitution possible? (a) Drawings etc. Only when these possibilities have been explored —plan, side and end views (elevations for the and exhausted without result should a proposed. technically minded) are usually all that is important activity be dropped. necessary. —if drawings are to scale, state that scale. (f) D-i-y equipment, constructional difficulty —if drawings are not to scale, say so. —‘projections’, orthographic or otherwise. An individual teacher or technician may be capable are difficult for the untrained and often unnecessary. of constructional work to a high standard. He may —a photograph, or good photocopy of one, can be be used to lathe and milling machine work, com helpful. plicated joints in wood etc. Others may not be so skilled or just not have easy access to the necessary tools or machinery. (b) Spell out all relevant d9tail
Checkpoints —if it is important for effective operation of a device that components are of a particular type and/or range. value —is the construction as simple as possible, etc. say so eg. for thermometers, consistent with being robust and effective meters, motors, elec in operation? tronic components, gauges and lengths of wires etc. —does it make maximum use, as component parts, of ready made items either already in the school or otherwise freely available? —for special commercial components other than common items like screws, 4mm plugs etc. give Documentation at least one current source name, address and telephone number, give catalogue numbers and prices. We have two staff maxims, at SSSERC, which others —if may wish also to bear in mind. a particular sequence of assembly has proved most effective, write your instructions in that sequence. (1) We are here to complement the roles of teachers and technicians, not to complicate them.’’ (c) Omit irrelevant detail (2) ‘Colleagues outside are quite capable of making mistakes for themselves. They do not require any or indicate where exact materials or dimensions assistance from us in the form of incorrect or are not critical. incomplete documentation. For example we have in particular instances (We don’t claim to aiwayslive up to these!) wasted a lot of time looking for particular specified materials where any old softwood When material developed in one or school is to be made faced board would have done the job.
5
6
Fig. 1. Moe[ loudspeaKer.
or ‘Nr’ can
of sheet npkate
laminated C core —
turns 30 of around wire
generator
connect to power signaL
L —core
at side tnp1ate from
flat magnet on opposite
C gripping core —
a send stamped, hold above desk addressed envelope clamp stand with for return.
Alternatively note the available, alone are but please
supplied with motor and gearbox at £6.30 + pp.
These control. available notes are us from and be will
the motor a servo to mounting pot angular for position
suitable control circuit. We explain also how to connect
prevents detector the difficult by affected visible being and light. we prepared have a set of notes giving a
phototransistor). infra filter red An eering front the science. over Construction of a servo system is not
photodarlington a matching diode and stage two (a course H grade in physics and in also H grade engin
device This consists (Fig. emitting an of 2) red infra strating servo motor control the in analogue electronics
Ferguson Edinburgh University of department. physics degrees few per second, makes them ideal demon for
as analogue came device an Their us Malcolm to from precision manufacture and slow rate rotation, of a
reflective using a of idea The 307-91 (AS switch opto motors 3) fitted with very large reduction gearboxes.
We have specially purchased a stock of quality
Microphone ‘ModeI Pulse Detector or
Servo mechanisms
260mm. Physics Notes
at present a based is 35mm on base can film diameter of
cans sheet and tinpiate be can tried. The use model we
Some experimentation usage the with a variety of of
equipment. spectrum heard, be can with prominent resonances.
our set-piece exhibitions be a generator power signal Foundation of complete and the audio Science
that is it basis the in-service for on other of side the accompanying work plate. the signal The should source
may
help indirectly. The material another has to use a sheet in by tinplate of magnet a (flat magnadur, etc)
writers.
If we
can’t
assist everybody directly the notes 1/0.6mm a round wire laminated C core which held is
We these hope notes prove will useful version One course to shown is in Fig. 1. Wrap 30 turns of
points.
activity, has and
scope design for
research.
author(s)
sadly have
neglected
a
or few
many of
these
long to construct.
It’s
what
jargon the
calls
a
pupil
still
receive
articles and
draft
publications
where
the to be resurrected
on
grounds the
it that doesn’t
take
curricular
material.
Although
it’s
all
obvious stuff,
we
an oldy-mouldy
which
has
been forgotten, but
deserves
we
have
sub-consciously
used
years for
in
vetting that people have
not
come across
it before. It
surely is
of
the obvious.
deals It
commonsense with
procedures
Science equipment
exhibitions
and have
been
surprised
Most
of this article
could
be
dismissed
as
a
glimpse
We shown have this model a at number of Foundation
Summary
Model loudspeaker displacement Set up in this test position it is a good illustration of the distinction between analogue and digital. / metahsed reflec tar ‘polyester film digital —place reflector .in front of device, output low remove reflector, output high source sensor analogue —move reflector to and fro in front of device, output signal varies in analogue fashion. opto device
c LED photodarlington
Fig 2. Reflective opto switch
The light emitting diode should have a suitable resistor in series across a power supply. Its forward voltage is 1 .8V and maximum forward current is 4OmA. Therefore 100R is suitable for a 5V supply (Fig. 3), cv 220R for a 9V supply.
The photodarlington collector voltage can be moni Hig.3. Analogue signal from reflective tored on a CR0. Test it out with a polished metal optc switch. reflector such as a penknife blade and you should find that it is a sensitive displacement sensor over a range of The device can now be used as the basis of a dis several millimetres. It is also very sensitive to rotation. placement sensor. A microphone or pulse meter is made by stretching 12 micron metalised polyester film across a small circular framework (Fig. 4) of about 1 inch diameter. The reflective opto switch should be mounted rigidly to this framework, 5mm from the centre of the film
metalised polyester segment of disk film stretched across tube
hole for attaching opto —device
mounting board for —device
Fig.4. Framework for microphone/ pulse meter
7
8
5. of framework Construction Fjg.
20mm
5 BA mm 10 or
i3 or 230mm — bBA
drills required
6 :Ae
•
2m o made from perspex,
Doard rectangular mounfing 1 Smm
12 rn
2mm
E
mm
8 cPru
at. rod round alloy
from made disk of segmenf
GJD
/
-Do /
mm -
diam. internal 2Smm
0mm gauge tube alloy “x1S
ight round tube from cut
8B foles 2
Araldite.’ with fixed and
tube
the across taut stretched The be as should appropriate. film bolts or polyester screws using assembly
metalised, the Finally board. for mounting ready the now is onto frame 5). device The (Fig. holes
mounting
opto
reflective the
fastens that bolt the with to accommodate prepared and perspex is 2mm from cut x 20mm 50
stripboard
the in be
cut
should 6. A slot in Fig. block, shown is mounting a rectangular Also
disk.
this from
layout
A
stripboard
framework. to the on off bolting cut is before width, radial 8mm of
A segment
the tube.
x
22mm, 30
stripboard,
inch 0.1 to on soldered be inside should snugly it fits that such necessary,
if worked, and
switch opto
reflective The
4). (Fig.
design
this
following rod alloy
aluminium
“round 1
from cut is
thick, 8mm
slavishly than
available readily
is
on
what
more
depend
about
A disk,
gauge. x 18 1”
tube,
alloy light
round,
well may
and
unimportant is
materials of
choice
actual of length a 10mm from is constructed
frame
The ___ The signal from the device will be a small a.c. signal 1 234557 on top of a large d.c. component so adjust the CRC for a.c. setting and maximum sensitivity. It can be used as either a microphone or as a pulse detector. For the latter we suggest using the neck (carotid) pulse. In view of the fact that this article has appeared in Physics 001 Notes” we ask that our physics teacher readers draw it to the attention of their biologist colleagues who in addition to having an interest in pulse detectors may well have an interest in small displacement sensors. The calibration of the device as a displacement O1’stripboard sensor, and its application, could form the basis of research for sixth year students whereas the construc 30x22mrn tion of the microphone, using a craft/design/technology approach, could be a project for general science students.
The reflective opto switch is available from RS Components 307-913, at £3.32. Metalised polyester film is available from SSSERC. See next article for details. The rod and tube can be obtained from Whiston and the specification and prices are shown below.
round light alloy tube, 1” x 18 gauge, 91p 1” round aluminium alloy rod, £3.32p
Mirror with variable focal length +5i CRC OV We were introduced to the usage of metalised polyester film by Eric Lucey of the Edinburgh Uni versity Film Research Unit. The film is a silvery sort of FigS. Circuit layout on stripboard
55mm hole
polythene syringe needle tube fixed to Petri dish
uhber tubmg nt. diem. 3mm syringe with Luer fitting
Petri dish base rnealised polyester
Fig.7. Mirror with adjustable focal length
9
10
“Purification of Proteins’’ (M85920/1, £25.10) kits.
‘Immobilised Enzyme” (M85910/9, £24.30) and the
£7.80).
From Harris Biological come
the
Sorry.
£28.10)
and
‘‘Enzyme
Production
Set” (ZEA-220-G,
We note
also the index
numbers are by out or 2. 1
duction to Genetic Engineering Set” (ZEA-240-P,
kits show on were; from Griffin Biological
—“Intro
have
caused
and
‘Alan thank
for it. tracing
applications
of biology. Typical of the wide of range
We
apologise inconvenience
the for
our
error may
to be reflected in the variety of kits concerned with such
eering and enzymic processes continued, as
last
year,
1090, in
line should 208. 240
read
The expansion of industrial usage of
genetic
engin
on listing page 63 be should decoded accordingly, ie.
and in (instead decimal 208 FO of 240). and BASIC The
Biotechnology
language program, be should BNE DO coded in hex
BEQ Thus code. page in part 67, 13 of the machine
Biology Apparatus
at up the writing stage of a giving BNE instruction a
running
‘6522 Accelerometer. The error was caused
below are that for catalogue).
West
Calder
School High reported
difficulties in
at the meeting. All catalogue Griffin
numbers quoted
Dow
Portobello
of
and School
High Alan
Russell of
(Please notethat Griffin launched
their
l984catalogue
However we concerned were two when teachers, Ian
Interfacing’
which seem worth hardly mentioning.
a of flavour exhibition. the
We are
aware a of minor of
number
errors
in ‘6502
a show huge at number of stands we all can do is give
at Exeter January. in early With so much apparatus
on
Erratum
in
“6502 Interfacing”
facturers exhibition held at the ASE Annual Meeting
Bulletin be up taken will a with review the manu of
Interfacing
Notes
The remainder the of ‘Trade News’ section this of
ASE Meeting Review
address shown
on the inside cover.
should
be
smeared
around all joints.
repairs.
Details and
are prices
available from the
found
to be
leaking,
a further thick of coating
adhesive
available as
before, as
are
spares,
servicing
and
be
by tested pumping and air out in a with
syringe.
If
Electronics
Limited. The
same
range
of scopes are
should be applied here. thickly Once set,
the seal
can
Scopex
Instruments
have
been taken by over
Scopex
around the ooen edge of the dish. Petri The adhesive
‘Araldite’
was
also used to fasten the polyester
film
over there from to
become ESP’s
new
General
Manager.
diameter,
rubber
tubing
to syringe a with Luer
fitting.
‘Gerrard
Biological
and Centre’
Neil Paffard
has moved
This was
connected
a with short length of 3mm,
internal
range
complements
and
supports that of
Griffin’s
syringe
disposable
needle container tube was
suitable.
anatomical
and osteological
models. ESPs
product
fastened
on with
‘Araldite.’ We found that a
polythene
Educational
and Scientific
Plastics
Limited,
makers
of
of
similar
diameter
to the
outlet nozzle of a
syringe, was
Equipment
Division, has
announced its acquisition
of
drilled in
base the
a
and small length of plastic
tubing,
Griffin’s parent
company,
Fisons plc
Scientific
for the film as and the air reservoir. A 5.5mm hole was
We used
base the of plastic a Petri as dish the framework
continue
until gives Griffin
further notification.
The variable
focal length
is mirror shown
in 7.
Fig.
of existing telephone numbers and addresses should
Scottish and ‘Northern customers. For the moment, packing. use
linkage.
to This
is
avoid
increases
in
telephone costs
for 25p a for strip 10 100cm. x
This
price covers
post and
extended
by
further a
Manchester/Wembley
exchange
both sides. price The is
£1.00
for one square
metre,
or
lished
between
Scotland and
Manchester
be will
Our stock consists
of 12 micron
film,
metalised
on
Manchester office. The telephone link already estab
Scottish
customers
are currently
served
by the the opportunity of purchasing small of amounts it.
therefore bought-in an offcut
roll
so that
have schools
completed by the
of
February end
1984.
able commercially in large quantities
only.
We have
operation.
Preparations
for the are move
expected to be film, so far as we have been able to ascertain,
is
avail
operation
in Manchester
and its
merger into is the a London thinnish grade, suitable these for purposes.
This
Wembley.
This
will mean closure
of the grades various regional of film and have found 12
micron,
which
housing
and aistribution
operations
waves at as Alperton, or this in article by pumping. We
have tried
Griffin
and George
are centralising
their air pressure ware either, as in the last article, by sound
a framework like a drumskin and be
can
displaced
by
Move
and
acquisition
or both surfaces, coated. It be can stretched taut across
thickness of and texture and be can supplied with one,
‘‘Clingfilm’’ which is manufactured Trade in News various grades any camera with a The last named kit can be used to illustrate the salting- sizes. The beam splitter also fits microscopy and out of proteins with subsequent purification by o mount. A short discussion on CCTV Sephadex ion exchange chromatography and gel projection will follow in Bulletin 140. filtration Cell biology One older technology has revived in the warmth generated by the flame of the new. We refer to the Harris Biological, always strong in this field, had renewed demands for glass distilled water for certain some interesting additions to their already impressive biological media etc. See the entry on glass stills below range. As well as some of their applied kits dealing with for more detail. tissue culture they had on show their ‘‘Leaf Protoplast Kit (M8245018, £11.95). This uses enzymes to strip Microscopes away cell walls from leaf mesophyll leaving isolated cell protoplasts which can be utilised for a number of Those wishing to service their own microscopes may physiological demonstrations. In genetics and cell find convenient Griffin’s maintenance kit (YSG-330- division two new aids are designed to assist teaching T. £35). This brings together sets of Allen keys. in these difficult areas. The Harris ‘‘Genetic Cards’’ watchmaker’s screwdrivers, dogwood pegs. lint free (M90025/0. £14.75) assist in the working out of genetic cloth, lens tissue, test slides, three types of lubricant ratios. A cell division card set, (‘‘Mitosis and Meiosis’ and a full set of instructions. The price of this M80001 /2, £9.75) is designed to ease the study of the comprehensive kit has to be compared with that of two different types of cell division. buying an ASE Technician’s Guide No. 1 ldirect from its at £1 and gathering ASE or frorn us, authors!> In the field together from ‘arious sources all the separate bits and all a matter of balancing pieces. As usual, its Aids for field biology were much in evidence ranging price. convenience against from inexpensive sampling nets from Irwin Desman to a sophisticated digital oxygen meter from Griffin. Of Griffin also launched a new range of microscopes particular interest among the former were inexpensive known as the ‘G range.’ There are four models from long handles for sampling nets starting with the a basic H-grade student instrument with mirror 1 .2m (AA2779 at £1.76) with a telescopic version illustration (Model G20, YSF-570-Y. £177.60) right extending to 2.2m (AA2780, £4.40). To accompany through to a sophisticated routine research/teacher these handles was a wide range of nets and frames. demonstration /college instrument the G1000 (YSF 590-A) at £574.26. Griffin’s newest oxygen meter, the model 60, (YAC £170) won’t be available for delivery until the Offord continue to refine and develop their OM series 462-G. summer. More expensive than many models but you of microscopes. The OM120 biological and 0M140 are paying for digital display, automatic temperature geological models can each be inter-converted using a compensation and the ability to display oxygen concen stage conversion kit. The resulting dual purpose trations as ppm. or saturation as well as temperature costs either £229 or £231 depending on instrument readings. which model you start from. The addition of an 0M180 35mm SLR camera attachment at £30.60 allows fitting of cameras of either 49mm or 52mm threads. Other Chemistry apparatus adaptors are available for other thread sizes. For the thermodynamicists there is a new electrically Pyser Limited have produced a small mains operated compensated calorimeter from Philip Harris (Cat. No. only enables (240V. 20W) sub-stage illuminator (35-300-1 25, £18.30) 042950/0) priced at £20.33. This not but for their popular ‘Technar’ model. accurate allowances for heat loss to surroundings, greatly simplifies calculations. It is essentially a Dewar ‘Microvideo’ flask fitted with a cork carrying a 12V heater and a thermometer (latter not supplied). It could be used We mentioned in last years review the approach of simply with a voltmeter and ammeter to measure energy closed circuit TV microscopy to the £500 barrier. A transfer from the heater to the calorimeter and contents. Philip Harris complete monochrome system Just dips but the use of a joulemeter borrowed from the physics below that mark at £492 (see p.801 of Harris catalogue). department will greatly simplify calculations. Failing (Cat. No. A similar system from Griffin (p.604 of catalogue— that. Harris have a suitable joulemeter Those who wish their Cat. No. YSG-400-J> is priced at £529. Offord’s system P26580/4) selling at £111.62. heat energy sells at £495 and has the additional feature of a beam pupils to have practice in calculating splitter permitting direct viewing down an eyepiece as transfers should not use this equipment! well as on a monitor. This accessory is available separately for £95. It will fit directly other microscones Johnson Matthey Chemicals whom we referred to in with the same riead size as the Offord models. Adapt Bulletin 134 have produced their new catalogue which ors are available for microscopes with different head can be obtained by writing to the firm at the address
II
2
have Limited. Griffins syringes Instruments acceptable fromMetraqram though cheaper
£675 at selling 0.lg) x using (2500 2500D and model kit Precisa the syringe gas their redesigning By
example for meeting, the at seen were bargains Some
kit syringe Gas Balances
heater.
a
expensive less
using and stills cabinet postage. and 35p plus packing P.
£3.50
for J.
Woods
of
their
one
from
‘extras’ the removing by £199) blue from pale or XL) white, (5, fawn in M, sizes Land
ES.51BW,
(Cat. No. still a cheap produced have Sons) four in available are They are distinguished. clearly
and
Flaig (W.
F. Exelo filters. micropore disposable lanthanides and actinides metals, elements; gaseous
ixpensive relatively and water deionised use than and liquid solid, used for are with colours Different it.
still
rather
a
glass purchase to cheaper be may it ments imprinted T-shirts wear to budding chemists your get
experi ‘biotechnology’ their of many to for is Table, biologists Periodic with the familiarity encouraging
the
by required
water volume the on Di Depending ASE, of at Exeter seen way, attractive Another
applications. some for important are resin of residues
from and ions metal from Freedom important. is water Society of Chemistry.
of
quality the where or hard is water the where resins the to Royal payable be made should copy. Cheques per
ion-exchange over
advantages have will stills Water £1.18 at members RSC price for the copies for with ten
£5.90 or copy per £2.70 at RSC be the from ordered can
watches. stop and blades these Now
RSC
members. to later on
and magazine
razor sided
single
boats,
weighing
flexible
jars’, ‘sweet Life”
“Time of readers to
only available formerly
were
lidded glassware,
disposable
as
such
commodities
These
Chemistry.
of
Society
the
Royal from available
useful other supply who also Horwell,
from
obtained
now
are information
other and
element of samples
each
be stock can current of Details
as
items. 12 per or 10
of
typical
pictures
coloured with tables Periodic
shown is pricing the where units as or lots complete for
accepted only are orders and £30.00 of value the to goods
tables
Periodic
for is
nrder minimum The
basis. served
first come first -
a QJM-230-B). on to (QJM-200-W pack out 20. of a sold for stock is of batch large particular a until
£11.80 to £10.20 from prices at holds sell and offer 29/32, 24/29 This Limited. R. Horwell A. by price at half
14/23, 19/26, available, sizes four joint Griffin. The glassware of Pyrex sale the is bargain better even An
from available also are the now clips 137 Bulletin in
to referred Clips. Previously Bibby Joint by condenser Pyrex. in sizes comparable
a
end of
lower the to be held flask can A receiving the for £13.47 with favourably compares This wall. light
x 16mm for 125mm 100 per £11.80 at sell tubes These
clamps.
retort laboratory use
of
traditional the said for TES-620-series). the in numbers
(catalogue
Griffin, from
be
could not
This
likely. less are much breakages and available also now are J. Beveridge, A. from and Lynn
simple made is
gassware of together
The fitting ation. and Mackay from available previously price, a
lower
or distill reflux for
whether
condenser flask and both at selling Pyrex and with quality
comparable a
of
tubes
tus
hold
can stand A single
the plate. along slotted borosilicate rimmed Co.) and Murray Samco(Samuel
be moved can clips both except Terry that ‘Duoclamp’
Enterprise’s Spiring to a similar manner in operated Glassware
This £8.75). (STE-950-P, stand semi-micro Griffin’s
was kits glassware jointed support for excellent An probes. pH oxygen or
with work for useful it makes size small the and stirring
efficient your support you ensure rpm for Thank 2500 to up of Speeds £19.95.
for available is SWP-104-520N) No. (Cat. adaptor
mains speed variable glassware. kinder to the them making required, if and, £44.00 costs
a It thus gauze, than rpm. 2400 up to more evenly heat distribute speeds also and of range a allows supply
power variable transmitters A heat good are £3.54). tops test-tubes. These ceramic 16mm x 150 into easily
fits 2’382153, No. (Cat. top the SWP-100-R) £5.45, No. ceramic and costs Cat. (Griffin microstirrer A
2907753) No. (Cat. model The nichrome finishes. and
sizes of variety a in tops solid ceramic use for with pods evaluated.
quadra- being produced have lrwins four legs bad, currently good!” meters pH of batch a with together
legs ‘three was Exeter at 1984 heard in One chant evaluation for future near the in a sample receive
to hope We GiPSI. on measurable parameters of
£155.00. down to kept range the extending thus available, now are £35.00) A,
a cost being with the cabinet than into trays rather two (WXA-554- accessory meter pH the and £37.50) 550-S,
into stand, pack the apart from The components, stand. WXA No. Cat. (Griffin module program GiPSI The
support horizontal im a and designed newly etc. taps
3-way T-piece, pipette, Orsat absorption syringes, an orders. receiving of
two eg. usual fittings the all includes The set volume. hours 48 within Britain of parts all to delivery free boast
gas a in change involving reactions studying for prices and competitive very at by schools required
GAR-380-M) No. a gas (Cat. syringe kit new produced chemicals the of many sell They cover. bulletin this on Also from Metragram were two small portable Miscellaneous battery powered balances based on load cell techno Some items which may find many applications in the logies. The models 500PJ (500 x 0.lg) and 5000PJ ‘Science’ options on ‘Materials” and “Energy” are (5kg x ig) were both selling at £410. Some items move given here. Sets of bar magnets, air screws, propetlors from the laboratory and find, after modification, a use on long shafts (for model boats), elastic bands etc., and elswhere eg. spindriers. Others are imported from the all of the equipment needed for ‘Science Horizons’ kitchen eg. the Salter TFE digital balance, (Griffin courses are available from Osmiroid. BCM-100-L) weighing on two ranges 500 x ig and 1000 x 2g and selling at £149.00 excluding the four A low voltage (12V) radiant heater from Philip Harris HP11 batteries. Another battery powered balance also (P28540/2, £14.40) is mounted between two heat comes from Griffin (BCM-200-D). Made by Polaroid resistant shields with windows and can be supported it has a capacity of 4.5kg x 20g (or91b x loz) with a price directly in a bosshead. A pair of solar panels (Harris of £29.50, the P100 battery costing an e’xtra £3.25. P30241, £90) can be used either in series or parallel.
Interfacing electronic top ban balances to micros Ideas for Education have produced an inexpensive seems to have many interesting applications from the metal strip bender (based on the design of the SSSERC studies of reaction rates to long term data logging (eg. model given in Bulletin 137) for £8.50—Oat. No. transpiration rates) with display on VDU. If you happen IE.0061. For use with the strip bender are metal strips to possess balances already fitted with the appropriate measuring 12 x 200mm x 26swg in packs of 20, each interface, the extra cost to ‘get started’ may not be pack of the same metal. Those are available from I for large. For example Metragram’s Precisa 15000E B (P.6 in catalogue) and Irwin (P.65 in catalogue). (1500 x 0.Olg) comes already fitted with an RS232 Metals available are aluminium (soft), Aluminium alloy interface. The cost of the cassette program for the BBC (hard), brass (soft), copper (soft), steel (mild). micro plus the interface cable is £25 + £1 pp. The program alone costs £16 + SOp pp. This program can Those problems often encountered in the use of simply plot weight against time (reaction rates etc.) or energy conversion kits, where the meter unit is grad alternatively give a bar chart and average for a set of ually dragged closer to the dynamo or to the turbine results. Other Precisa models can be fitted with the unit and the belt slips, are over if you look at Irwin’s appropriate interface costing £65 (300MC and 2500D Malvern Energy Kit (page 75 of their latest catalogue series as described above) or £120 for the dual range No. 16). The sets of units—motor/generator, lamp, 300/3000 series plus £50 to cover the engineer’s time turbine pump, flywheel etc. are mounted on rigid bases and travelling expenses. Philip Harris were exhibiting which can be quickly locked together by a plug and an Ohaus Model B top pan balance fitted with an socket system without all the hassle of bench clamps. RS232interfaceand using CEO software. The interface, Toothed belts ensure easy running and freedom from Cat. No. C13912/1, costs an extra £58 if fitted to a slipping. balance at the time of purchase, but for existing balances the cost of carriage has to be added on. The Digital thermometers seem to get cheaper all the accompanying software is available on cassette time. One of the cheapest we saw was the Model (Cl 3910/8. £18). 506-1 0700 from Hero Electronics. It has an accuracy of 0.2° between 0°C and 40°C, 04° between 40° and Many of you will possess Oertling TP balances and 70°O and 1.0°C between 70°C and 99.9°C. This is they too can be used, but at varying expense depending available from Artec and I for B (IL.0071) for £21.50 on the model. The models supplied as standard for with a 9V alkaline battery. some time in the JC12 (1000 x 0.Olg), HB63 (300/ 30 x 0.Olg/.OOlg) and HC22 (2000/200 x .1/.Olg) Smith’s countdown alarm timer, that valuable aid, ranges are now the “fifty” version ie. have catalogue measures lapsed time from 100 minutes to an accuracy nos. HB63/5O and HC22/50. These have a BCD output of 1 second. It can be clipped onto a lapel or held on a which can be connected directly to your Beeb with a (ridge door with the magnetic pad. It is available from cable costing £45 (Cat. No. F5261). Leads are also avail many stores and suppliers—price from Artec and I for able for PET, Apple and 380Z. The software may be F is £9.50. copied free from Oertling. Those interested in making a copy of the software should phone 029-483-3395 for An extremely robust three way plastic T-piece valve details. in which either two or all three outlets can be inter If you bought your Oertling some years ago it may be connected is in fact a spares for the beer line used by a the ‘zero zero” version. These lack a BOD output and well known brewery. I for E are marketing this valve one cheap solution is to use the analogue output on the for approximately £1, right hand side of the balance with a borrowed ADO to link it up. Alternatively an interface card can be fitted At last the simplest yet 13A plug to wire up. No tools for £150 (includes parts, engineers’ time and travelling other than a 1/ or ip piece to act as a screwdriver for expenses for on site fitting I. The Mettler PB Series fastening the top are needed for the ‘Handiplug’ from require an interface board (Griffin BFG-221-502J. Artec (I for F). It contains a wire stripper anu the ends £95) and a connector. This pricedoes not include fitting. of the conductors are clipped on to the pins. Price £1.
13 Changes of address and agents CMOS RAM, EPROM 2 (28) installed with a new range of programs and a number of sensor modules on W.P.A. can now be contacted, not at Saffron Walden show. Of interest on EPROM 2 was a facility to output but at the address shown inside the cover. information to a standard parallel input printer. Crude Rotheroe and Mitchell deal now with alt Panax graphic plots of information gathered by VELA were products, previously catered for by E.S.l./Nuclear. demonstrated. A record of the states of light gates at recorded times during a multi-channel experiment was Electrical safety shown. Also seen was a digital logic tutor board in the final stages of development. It is programmable from ELCB in a plug EPROM 2 and has overlays for different gate combin ations. B and R relays now manufacture a plug with an integral earth leakage circuit breaker. This can be used As well as working with VELA itself, the sensor pin Set to trip-off in place of a normal 13A three plug. modules (pH, magnetic flux, temperature, light etc.) within 3Oms of the passage of any the mains supply have stand-alone capability by connection to the E.E. exceeding 3OmA it should earth leakage current General Purpose Scientific Meter (GpSM)-(25). As reset button is on provide an extra level of safety. The one slightly cynical observer put it:— Could this be the rear of the plug, thus discouraging it from being called the Gipsum?” The sensor module is connected used without thought. A test button simulates faults via two prong contacts ‘piggy-back’ style on to the to check the operation of the breaker. In addition a neon meter module. It has a resolution of 1 part in ±1999 on on the front lights if the socket polarity has been a 17mm digit LCD display. Fig. 1 shows the meter as a reversed. This device can be found in most electrical thermometer. shops and large stores for £16-17 but can be obtained from Griffin (Cat. No. ECA-600-070L) or Irwin (Cat. No. RA2619). We do not consider that ELCBs (or residual current detectors—RCDs) should be used as the first step in a general solution to electrical prob lems. It is better that equipment be maintained, kept or brought up to acceptable standards and the environment made as safe as possible. After that has been done it is possibly wise to add on such a device as an extra level of safety in particular situations eg. aquaria power supplies.
Splashproof power supply
Another device which may be of interest to those using low voltage obtained from power supplies in watery’ environments is the splashproof power supply from Irwins (Cat. No. EA2978 at £58.10). We saw it working in a tank whilst undergoing a thorough drenching. Our comments about not replacing good practice with gadgetry apply here too, but it could well be useful in some applications for biologists (eg. experiments in a greenhouse) and chemists (eg. conductimetric or electrochemical work involving electrolytes). The output is 6 or 12 Volts d.c. with a maximum current of 5A. r Microelectronics Fig. 1
Viewing the vast range of microelectronics apparatus, Also on show from E.E. was a Sweep Frequency one pondered how wonderful a science teacher’s job Generator (6O) which can be used for plotting reson could be if he/she had infinite amounts of money. ance curves from LC circuits and air columns as well as Hardware is becoming more presentable and versatile amplifier and filter characteristics (sweeps 200 and software more user-friendly. Hz-2OkHz in 20s with interface to VELA).
The ever-enthusiastic Educational Electronics team A Buffer Board at £28 gives ±25V overload protect had an impressive selection of new equipment on ion to the 16 I/O and four control lines on VELA. I/O display. VELA was boasting a new, improved board lines can be configured to the user’s requirements and layout with a number of add-on goodies:—gone is the the board has a 26 way IDC connector so that a micro funny decimal point, all models now have low power can be connected to VELA at the same time.
4 The E.E. stand had an interesting Video Camera complement a book, ‘Electronics, An Introduction’ by Interface (174). Frame capture in 4s and 64 levels of Alan Hedley (published by Harrap ISBN 0 245-53905-0). grey are achieved with a RML38OZ. Colour enhance ment of images and an interface for the BBC micro are The Middlesex Science and Technology Education available with this package. Centre(MSTEC) had two modules of interest. Firstly there is an S3 course called ‘Starting Electronics’ The E.E. new equipment list ends with 3 items of which has equipment and notes apparatus for teaching microelectronics from S3 to for 32 pupils (in pairs) and a set of teachers notes. S5/6. First is The complex system costs the BBC Microtechnology Breadboard kit £550. which is used in conjunction with the BBC’s Radio- vision Series due to start on Monday, 12th March at Secondly MSTEC are developing a ‘Control Tech 00.30 hrs. Each kit is suitable for four students (2 per nology’ module. At present there is a set of 13 assembled board) and costs £40. Further details of the Radio- printed circuit boards and a teacher/pupil resource vision programmes can be obtained from The School book is being developed. Any school interested in Broadcasting Council for Scotland (BBC). joining the ‘Control Microelectronics’ should contact ST Secondly is the Intro Board at21 .60 which has four M EC. 16-bit IC holders, a debounced switch, clock oscillator In the ASE and display/bit setting switches. It can be used in Members’ Exhibition was a generic development of the existing courses or as part of a ‘Microelectronics for Locktronics principle for micro electronics teaching. All’ course with the ‘Introducing Electronics’ book from This system called ‘‘Rocktronics’’ has been developed the publishers Nelsons, which is due to be published by Richard Taunton College. Circuit diagrams and sometime in February. construction information are available for £2 from K.C. Dunn at the college. Finally the Analogue Interface Tutor Board comes with a number of circuit ‘building blocks’ (46) which A ‘Locktronics File’ is soon to be published through can be used with a microprocessor/microtutor. These the Microelectronics Education Programme (MEP). include an 8-bit D to A converter, an op-amp which This will comprise worksheets and additional infor acts as a comparator, voltage trequency to converter mation from many sources. (on-board) and an audio power amplifier (on-board). In a similar vein, A. M. Lock were demonstrating Edu-Elequip had a number of Proto-boards with their LK82 Timer Kit as part of the Locktronics series. integral power supplies and a breadboard matrix. The LK82E ‘essentials’ kit at £39 has items specific These can be any combination of single or balanced to the 555 timer based systems with other parts being 5V and 9, 10, 12 or 15V. They vary in price up to about borrowed from kits you may have already. The £40. complete kit with all components is £62. There was also news of an LK83 Systems Kit which Lock hope to be Limrosehad acoupleof interesting new developments. available by March. This will include circuits with A single-board microcomputer currently called the counters, registers and 7-segment displays. MHC-80 is based on the Z80, with 2K ROM and 1K RAM and 2 PlOs for interfacing. The micro looks like Northern Computers had an interface on show called the Multitech Microprotessor MPF-1 betore it was the ‘Micropulse Youngtrainer Robotics Device’. A upgraded. The board layout has not been finalised but teaching pack which gives a course in control technology they assured us that the completed version would + the interface is available for £80. appear soon as part of the Tutorkit apparatus, complete with comprehensive instruction manual. The anti Electronics Kits are now becoming available for the cipated price of £75 + £7.50 for mains adaptor seems Independent Schools Microelectronics Centre (ISMEC) good value for a machine-code and control-tutor. The ‘‘Electronics 11-13’’ courses. The Griffin Electronics Scottish agent for Limrose Tutorkits is IMS. Also from 11-13 Kit (XLD-870-B) is available for £55. The Unilab Limrose was a Tutorkit Karnaugh Map Tutor. version ranges from £25-32 and the Harris Basic Karnaugh mapping principles can be demonstrated Logic Module Set (P53470/0) which is based on the with up to 4 Boolean variables on a matrix of 16 LED ‘Worcester’ circuit board at £34. displays. Production quantities should be available Interfacin by 15th March, 1984 at £21 (Kit) or £27 (assembled and g tested). Perhaps the saying in science and technology teaching at the moment is— ‘If it moves, interface it.” Newcastle Science and Technology Education Centre The main equipment suppliers certainly give this (NESTEC) have a number of self assembly kits which impression with microcomputers and peripherals could be usefulfordemonstrating electronicstechnology. dominating their stands. A ‘Logic Kit’ with 23 logic modules is £36. Modular Technology Electronics’ kit (25) with plug-together Ideas for Education were displaying the Barr Micro components and ‘Individual Electronics’ kit (20), both computer Interface Unit for the Apple Il/lie. The
15 r interface has 4 analogue input channels (0 to + 3.06V). Microcomputing There are three digital input channels with ±50V overload protection. There is also a ‘test voltage The Griffin and George stand had three Sinclair ZX facility for producing a suitable voltage for the analogue Microdrives (CRA-770-560D, £43.44) linked in to a and digital input voltage ranges. Cost is £65. three Spectrum network using a simple file server. The microdrives were impressive in operation and were The Newcastle Science and Technology Education said to be reliable. Griffin are hoping to offer a network Centre (NESTEC) have a number of self assembly kits package in the near future. which could be useful for demonstrating interfacing techniques. These include an ‘Interface Unit’ for the Mercian Computing were demonstrating an interest BBC micro with 8 inputs and outputs as well as relay ing package called ‘Understanding 6502 machine code modules with 4 two-pole changeover relays. This will with the BBC computer by A. G. Saxton. The package and cassette with three be available late February 1984 and will cost £25 + £5 (16.95) includes a textbook for power supply + £5 for the relay module. Also programs:— available by March will be a Basic Buggy, powered and controlled by the BBC micro for £40. i) SIM can simulate every typeof 6502 instruction and shows how registers, memory locations Science and Technology Education on Merseyside and status flags change, as an instruction is Ltd. (STEM) in conjunction with the Computer Science executed. Department at Liverpool University have developed a ii) NUMBER enables binary—denary—hexa ‘Modular Micro-computer Interface’. It is designed in decimal integer conversion. 3 rts:— iii) BDB is a machine code monitor which is also available separately at £6.95.
I) an adaptor board (PET, BBC or Spectrum). Philip Harris had a vast range of new programs on ii) an opto-isolated input or output board. both cassette and disc for the BBC micro. These cover iii) a working board. A starter pack which includes many physiological processes, chemical bonding? thethree boards, instruction manual, teacher’s analysis/simulation and physics applications/simula notes and software is available for £49.50, tions. Also available was a Cabel CE 370A (P89045/0) post and packing. colour monitor for a reasonable £200.
Physics apparatus Griffin and George were demonstrating their new interface for the BBC micro (CRA-950-O1ON). Most of Griffin and George had a number of physics items you will be aware of the I-Pack version for the Spectrum. worthy of mention. Two new stroboscopes were on The BBC version is identical in performance but is show. The more expensive Digital Xenon Strobe Model connected to the 1MHz bus via a ribbon cable arid has 60 (XBG-580-O1OD, £155) has a flash rate range from its own power supply. The price is £52. Also available 1 to 250 Hz and external triggering sockets also enable is an interface manual CRA-954-520M which includes it to be used as a frequency meter. The cheaper Xenon 2 cassettes with 15 programs. (12.50). Strobe Model 40 (XGB-600-O1OF, £139) has a calibrated dial for flash rates but without frequency meter Griffin’s GiPSI can now be connected to a micro via capability. the Computer Adaptor (WXA-150-E, £84.50). Connect ion to a chart recorder or oscilloscope can be achieved Also on show was a Current Ramp Generator (XKC with the Recorder Adaptor (WXA-154-D. £49). 600-S, £50) which can supply a linearly increasing or Software for the former is soon to be made available. decreasing rate of current between 0 and 1 A. This device is designed to examine self and mutual induct Irwin were demonstrating a development prototype ance as well as standard experiments in electro of an interface called the ‘Interactive Microcomputer magnetism. Peripheral’. As you may guess it’s a large device! Facilities at the moment include 8 input and output A digital Coulomb Meter (XJC-200-P, £36.40 + channels, 12V and 5V supplies, analogue to digital £1 .64 for the battery) was on show. Designed for and digital to analogue converters, light detector, traditponal electrostatics experiments, it is capable of thermocouple and microphone inputs, signal generator measuring in the range from inC to 1999nC. and EPROM programmer. Software is also being Griffin have 3 redesigned Optical Sets (2 bench sets) developed and will be available early next year for and a new raybox and raybox set. Other new equipment around £500. includes a ‘White L;ght Hologram’ (XFW-440-W, £23.90), which can be viewed in daylight and a Laser Also from Irwin is an Interface Unit (EA2088, £35.75) Diffraction Set (XF\/-630-A, £26) which can be used in which provides 16 lines of buffered parallel I/O from conjunction with a book, Images’ by Prof. C. A. the BBC micro to the PIPPA range. Taylor (XFV-634-530Q. £4.53).
16 Irwin have a new Xenon stroboscope (RA0374, passing into a different medium. It works well and at £84.80) which has a flash frequency range 5Hz to £26 is worth inspection. 100Hz. Frequency is read as flasheslminute on a calibrated dial. For those considering replacement of their unbalanced or noisy air track, UNILAB have a new track Linsteadwere demonstrating with anew Triple Stabilized accessories (432.100, £170). The kit has two power supply (S14) 200g with the following provisional vehicles with carriers to increase the mass specifications. It to 400g if has 3 separate outputs of ±12V and required. Also included are rubber +5V, all of which strip bumpers and can be used at the same time. The snowploughs’ for elastic collisions 12V outputs have a rated current and a facility for of 0.5A and the + 5V a inelastic collisions. A pulley is provided rated current of 1.OA. There is ±-50V overload for hanging mass accelerations as is an ‘Electromagnetic Propulsion protection for connections to all outputs. Unit. This is a coil which gives a force to a vehicle which is proportional to Irwin have the applied current. An a new 10 MHz oscilloscope (RA3020, extremely quiet Air £175. track blower’ (432.101, £85) may well save a few teachers’ voices, if not their EA’s pockets. Ideas for education market a Wave Machine which consists of about 2m of wooden slats joined in parallel to each other. A section of these are weighted to simulate the change in wavelength and speed of a wave
Committee.
A
‘national course’
is
* which one
has been approved as to its by content the National in-Service
University of Stirling
Department of Education
B.Sc., M.Ed., C.Eng., M.l.E.R.E.. M.lnst.P.
Course Director: R. Mr A. Sparkes
Glasgow 4QA G61
Bearsden
Andrews St. College of Education
In-Service Department
details of course the may be obtained from:
Teachers
wishing
participate to
should
make application through their local authority. Further
main
principles
and
important
strategies and skills entailed in
teaching the of electronics.
course The
will
to aim
familiarise those
who
be will the in fore-front future of developments with the
throughout the course evaluation for by course members.
A full
range
of electronics
and
microprocessor
equipment and teaching materials be will available
qualified teachers.
computing; strategies
teaching for
electronics
and microelectronics;
the supply
and training
of
General
and Credit
Level courses;
electronics as
a component of
physics, engineering
science
and
Consideration
be will given to the
following issues: electronics and microelectronics for Foundation,
light of the microelectronics revolution.
The
course
will
focus
on
why, what
and how
electronics should be taught in secondary schools, the in
electronics be will assumed.
education
lecturers
and
teachers in secondary
schools. Some interest
and in knowledge
basic of
course This be will
special of
interest to
curriculum developers, advisers and inspectors, colleges of
2-6 July, 1984
St. Andrew’s College of Education (Bearsden Campus)
Electronics and Microelectronics in Secondary the School
COURSE N.C.6 NATIONAL*
Microelectronics Education Programme (MEP), Mrs Beth Bevis, Ronsella, Lordswood, Highbridge, Eastleigh, S05 7HR.
Middlesex Science and Technology Education Centre (MSTEC), Middlesex Polytechnic, Trent Park, Cockfosters Road, Barnet, Herts., EN4 OPT. (Tel. 01-440 5181 Ext. 307/8).
Thomas Nelsons (Publishers), Mayfield Road, Walton-on-Thames, Surrey, KT12 5NP. (Tel. 0932 246133).
Newcastle Science and Technology Education Centre (NESTEC), Newcastle Polytechnic, Kielder House, Coach Lane Campus, Newcastle upon Tyne, NE7 7XA. (Tel. 0632 663409).
Northern Computer, Education and Training Division, Churchfield Road, Frodsham, Cheshire, WA6 6RD.
Oertling Division, W. and T. Avery Ltd., Smethwick. Warley, West Midlands, 866 2LP. (Tel.021-565 1919).
C. E. Offord, Ticehurst Road, Hurst Green, Etchingham, Sussex, TN19 7QT. (Tel. 0580 200739).
Osmiroid Educational, E. S. Perry Ltd., Osmiroid Works, Gosport, Hants., PO13OAL. (Tel. 032923245).
Pyser Ltd., Fircroft Way, Edenbridge, Kent, TN86HA. (Tel. 0732864111).
R. S. Components Ltd., P.O. Box 427, 13-17 Epworth Street, London, EC2P 2HA. (Tel. 01 -253 1222) Order Dept. 01-2533040or01-251 1676).
Richard Taunton College, Highfield Road, Southhampton S09 5G F.
Rotheroe and Mitchell, Victoria Road, Ruislip, Middlesex, HA4OLG. (Tel. 01-422 9711).
Royal Society of Chemistry, 30 Russell Square, London WC1B 5DT. (Tel. 01 -631 1355).
Science and Technology Education on Merseyside Ltd. (STEM), STEM WALTON Unit, 65 Walton Lane, Liverpool, L44HG. (Tel. 051-207 1869)
Scopex Electronics Ltd., 63-65 High Street, Skipton, North Yorkshire, BD23 lEE (Tel. 0756 69511).
Spiring Enterprises Ltd., Westbrook Lodge, Bognor Road, Warnham, nr. Horsham, West Sussex. (Tel. 0403790140)
Unilab Limited, Clarendon Road, Blackburn, Lancs., BB1 9TA. (Tel. 025457643/4).
W.P.A. Ltd., Old Station, Linton,Cambridge, CB1 6NW. (Tel. 0223892688).
K. R. Whiston Ltd., New Mills, Stockport, SK124PT. (Tel. 066342028).
P. J. Woods, Sycamores, Westfield Road, Monmouth, Gwent NP5 3HX. © SSSERC 1984 (Copyright is held to be waived only for bona-fide educational uses within Scottish schools and colleges in current membership of SSSERC).
Trade News —ASE
annual meeting trade review 14
Interfacing Notes —erratum in
“6502 Interfacing” 10
—variable focal length mirror
—model microphone and pulse detector
6
—model loudspeaker
6
Physic Notes —servo mechanisms
6
Foundation Science Notes —checklists
for apparatus
3
—bell-jars
2
Safety Notes
—syphons and cylinder
2
CLEAPSE Guides
1
—cost index
1
—CLEAPSE—2lst
1
Introduction
—ASE Annual meetings
1
Page
CONTENTS
BULLETIN 139 February 1984 S.S.S.E.R.C.