Microscale Chemistry from the UK
There were two basic strands in the microscale movement in the 1980s. One was developed with the aim of introducing practical work to countries which do not have school laboratories and fume cupboards, chemicals having to be stored in poor conditions, lack of money, difficulty in finding well-qualified teachers and where there are poor communications between centres. The kit developed by the Radmaste Institute was taken up by UNESCO and is used in many schools in Africa and Asia. Eastern European schools are using the kit imported from the UK.
Other centres started in the USA pioneered by D W Mayo, R M Pike, S S Butcher, K L Williamson, M Singh, B Mattson at Creighton University and S Thompson. There are many articles in the Journal of Chemical Education. These chemists found that there were significant educational advantages in working at the microscale level for college and University students. Also the techniques contributed to the environmental, sustainability and “green” aspects of the subject.
An attempt to supply the Radmaste kit to schools by the RSC had a poor reception in the UK. The book which accompanied the kit is excellent (J Skinner (ed), Microscale chemistry, experiments in miniature. Cambridge, UK: RSC Publishing, 1998. Download selected sections for free at http://bit.ly/rscmsc) After all, UK schools, in comparison to many countries, have well-resourced labs with fume cupboards and technicians available to prepare and deal with waste. There is also over a hundred years of tradition in using familiar chemistry equipment such as test tubes, Bunsen burners, flasks, tripods, etc so why use plastic syringes, Petri dishes, plastic sheets and spirit burners as shown the picture from Retford Grammar School in 1917. it is easy to criticise the techniques without actually trying them but here are some of the advantages.
Microscale procedures are safer than the original demonstrations because of their size. The classic reduction of copper oxide by hydrogen had resulted in many serious incidents and the prosecution of a teacher in the UK. The microscale version is safer because an explosive mixture of hydrogen and air cannot be made. Electrolysis reactions often produced toxic gases which affected asthmatics but dealing with volumes of less than 10ml cause no serious issues and yet the chemistry is plainly evident to observe. The cracking of alkanes can lead to explosions caused by the suck back of cold water into a hot glass test tube. With the microscale version, this cannot occur. An objection is that a class cannot see the procedure but modern projection technology overcomes this.
Reduces practical time to allow for more discussion and questioning
Management of time and lesson structure is of the essence in teaching. If demonstrations and practical procedures take too long and have to shelved to the next lesson, continuity is lost and the subject can become disconnected, not understood and in the end boring.
Reduces aimless walking about by students and hence better classroom control
Much of the time wasted in lessons is caused by students moving around the room to find sinks and balances and collecting chemicals and equipment. This can lead to poor behaviour but microscale activities can be carried out in a small area of the room. In fact, the student can work in pairs or even on their own. If a student makes a mistake, it very easily rectified. Another revolution is that as the quantity of liquid used is in the most 2ml, with practiced techniques, students sit down to carry out the activity.
Easier for students to manage
Recent observations are that the use of microscale are easier to manganese by the students. They have to observe macro events, follow practical instructions, try to picture and understand events at the sub-micro level (modelling) and in chemistry we expect symbolic representations (formulae, equations ) of what is occurring.
This has been connected with the how memory works during learning learning as the short-term working memory is quite limited in how much it can hold. It is hoped that research may be soon undertaken in this field.
As an example, working with chemicals on a plastic sheet with notes below is much more efficient in time and understanding of procedure rather than using test tubes. Using pipettes as burettes allows the teacher to focus the student on the chemistry of a titration rather than the equipment. Once the chemistry and tricky calculations are established, the standard equipment can be introduced.
If equipment is too expensive, the school may not be able to buy sufficient equipment so students have to work in threes or even fours. This usually leads to some students in the group disengaging from the activity. Microscale equipment is mostly plastic and even balances weighing to 2 and even 3 decimal places can be found for less than £10; and it is accurate. A full size Hofmann voltameter would cost over £150 the glass, the taps and the electrodes are easily broken. I have managed to make one for less than £20
Dealing with waste is of great concern to all countries now. One pioneer of Microscale Chemistry in the UK, Stephen Breuer said, why make 5g of an organic chemical, use 0.1g for spectra and experiments and throw 4.9g away? To remove the chemicals on a plastic sheet a paper towel can be used to wipe the liquids away. There is also a “green” agenda that can be met.
Reduces time in preparation, clearing up and disposing of waste
The UK is lucky in having technicians do a lot of this work. This is not true of most other countries where the teacher (hopefully with time allotted) can do this work. But this area is still a time-consuming business for the teacher who may through exhaustion perform a demonstration rather than allow students to experience the practical work.
Quantitative results and data manipulation are possible
In fact a lot of good science can be carried in comparing the results from different methods. Accuracy and precision are necessary in science but examinations are passed by understanding the subject. Some of the results obtained by this work have been very encouraging. The combustion of magnesium to illustrate an increase in mass of combustion is traditionally carried out in a crucible but with often poor results. Using magnesium sandwiched between 2 brown bottle tops, held with nichrome wire produces excellent quantitative results in the space of 15 minutes for students.
Uses modern materials and equipment
Physics and biology are using more up-to -date equipment than chemistry. In fact the traditional lab of today is very similar to those in the early part of the last century look carefully at that photograph from 1917!). Many think that pupils cannot cope with the manipulation of such equipment and yet they can text accurately, play video games and apply make-up in a car on a bumpy road or on the subway! It does need a little practice but then any technique does. The Bunsen burner is overused in many procedures but it is looked upon as an essential part of chemistry in the UK. The dehydration of hydrated copper(II) sulfate(VI) is just as efficiently carried out using a small spirit burner and this avoids the subsequent decomposition of copper sulfate(VI) to copper(I) oxide and toxic sulfur dioxide and trioxide that occurs with a Bunsen burner. Events like this have necessitated the removal of students from the classroom and even taking them to hospital with breathing difficulties. This would lead to an investigation by the UK Health & Safety Executive.
A laboratory is not always required
This is not always a desirable advantage but it can very useful at times. I have delivered this course in ordinary classros, boardrooms, libraries and even in television studios although this was in Kuwait.
Carrying out procedures quoted in text books but said to be impossible to perform in the laboratory
The Haber process for making ammonia from nitrogen and hydrogen and the Ostwald process for making nitric acid from ammonia and oxygen can be demonstrated in a few minutes. These are very important industrial processes required for the fertilizer industry. Even the hydrogenation of propene is possible.
Images can be projected onto a white board using a webcam or video microscope
It is claimed that the procedures are too small to see demonstrations but by using web cams and USB video microscopes (see pictures below), both costing about £50, it is possible to project images on screens. There are some very beautiful and interesting pictures that can be taken.
Photographs can be taken by students for their notes.
They can also be videoed. Many of the images are visually extremely beautiful and attractive.