March 2010

The unique aspect of science as a subject in school is the combination of rigorous intellectual challenge and motivating practical activity.  As teachers it is up to us to ensure that we do the best by our subject and our students so that their school lessons echo the science done in the “real world”

Much is made of the risk-averse culture and “health and safety” is used as an excuse not to engage with practical activity in schools.  But we owe our learners the best possible experience of science and this article points out some of the strategies we can use to accomplish that aim.

When we take students through a practical science lesson we are reflecting the experimental science that has been done for thousands of years.  Jean Baptista van Helmont (~1580 – 1644) was one of the first to use quantitative measurement in his famous willow tree experiment. In van Helmont’s experiment he weighed a pot that contained dry soil and a willow sapling from which the soil had been washed. After planting the sapling in the soil, he added no further soil for the duration of the experiment, and he watered the sapling with pure rainwater only - not with mineral water or well water, which might have contained dissolved earth.   

He then waited for five years – just watering his plant.

At the end of five years he carefully removed what was now a tree from the pot, weighed it, and weighed the dried pot of soil. The soil had lost very little of its weight, whereas the tree had gained a great deal of weight. Van Helmont concluded that a tree was not composed mostly of soil – the soil was still in the pot - as had been thought before.  He worked out that the tree was composed mostly of water which had somehow been transformed into tree. In fact he had recorded photosynthesis at work. We could perhaps say that he should have repeated the experiment, set up controls and certainly reviewed his hypothesis to come up with a new experiment and then tested that.  He was, in fact, busy with all sorts of other investigations including some less scientific ones which involved alchemy and astrology.

Before and after van Helmont there were generations of scientists carefully observing, measuring, recording and repeating their experiments, striving for their Eureka moment.   Many of them had to first make their own apparatus – this is reflected still in some school science labs which are lucky enough to have a skilled glassblower on the staff – to the endless fascination of the students. 

We need then, to ensure that our students are fascinated, motivated and engaged by their practical science.  My organisation, the Association for Science Education, has long been associated with practical science, effectively done.  For many years, teachers have exchanged imaginative ideas through our publication, School Science Review – in fact the first edition contained the following gem:

“Genuine research into the unknown will provide the stimulus required by capable boys with alert brains” 

(Please note - the Association at the time was concerned only with boys’ schools!)

Currently we publish the highly readable “bible” of safety in school science “Be Safe”, which reflects our concern that teachers may shrink from doing practical activity because of fears about safety.  We like to guide teachers into what they can do, rather than telling them what is impossible.

To develop this theme, the Health and Safety Executive holds common views with ASE on this matter. On their website, HSE  have a wonderful illustration of a class lined up in full protective gear to watch paint drying – needless to say they look a tad bored.  The point that HSE are making is that school practical activities are not “banned”.  All that is necessary is a sensible risk assessment and practical can be both safe and exciting.

Recently, ASE has been engaged on a pair of projects, along with a number of partners, that highlight further aspects of the practical nature of school science.  One of these “Getting Practical” focuses on the meaningful nature of practical work.  For teachers, this means making sure that they are clear about the learning outcomes associated with the practical work, reflecting on the sessions, encouraging discussion with students and so on.  Interestingly, the approach taken by Primary school teachers in all that they do – lots of discussion and questioning before the activity, groups taking part and then plenty of time to compare notes after the activity lends itself admirably to this end.  In secondary schools we are inclined to rush the activity through and not fully discuss what happened, concentrating on the experiment itself.  This can have a detrimental effect on the learning which takes place especially if the expected result is not forthcoming.

Another current project explores the idea of using the outdoors to good effect in practical science.  Again this reflects the science done by amateur enthusiasts in years gone by when careful measurement of gradual changes led to enormous discoveries.  The work of Charles Darwin comes to mind.  Darwin built up his theory of evolution from huge amounts of observation over long periods of time using the immediate environment of his home.  This might correspond with the large telescope experiments that take place today or the observations of living things in their environments that is made possible with the use of miniature cameras and sensing devices.  These are assisted by technology, of course, but none the less painstaking.  For school science, the possibilities for engaging practical work from the local environment or further afield are many.  Helping students to make links from the science that they are doing at school to the current exploits of scientists is important, so that they realise that there is a continuum of practice.

The educational purpose of practical work in school science could therefore be to demonstrate or illustrate a phenomenon that has been taught.  It could be to practise a technique or to help develop motor skills.  It could be used to challenge students’ thinking and it is quite likely to be a combination of these and other aspects.  We should never however, overlook the motivational purpose.  The opportunity to bring science alive and add excitement is priceless and we should use it as much as possible.  One of the great benefits of teaching science is that we can inject fun into the school day.