One of the main advantages of teaching and doing practical science is that it can help stimulate and satisfy the curiosity of all pupils, including those with special needs. The new national curriculum continues to stress the need for “experimental and investigative science” (a slight modification of the investigations of previous documents).

The experimental and investigative side of science requires the pupils to have the curiosity and motivation to want to do the activities. Some pupils do not seem to have any curiosity at all. Perhaps they have not been encouraged to ask questions at home or have felt that because everything was done for them, there was no need to be curious. Things just happen!

We need to stimulate pupils to ask “how?” and “what if?”. The teacher can then use the situation to the best advantage to say “Let’s find out”. This becomes a great opportunity to teach the basic skills of “finding out”, the skills that are now listed in the new curriculum documents as “Programme of study” along with the SC1-type skills.

Teaching investigative skills

The science programme for pupils should always be part of a structured, well-planned curriculum covering all the areas of science at the appropriate key stage. Pupils, at whatever level of operation, should be encouraged to ask questions about the material, experiments, their surroundings, the environment and themselves.

Within the context of any topic they should be taught how to use apparatus and equipment and to take accurate measurements during the course of standard class practical experiments. But in an investigation they should, ideally, be required to make their own decisions on strategies and methods. They will, of course, be using some of these previously taught skills. The new science national curriculum seems to have backtracked on some of the ideas of pupil-led “whole” investigations and come down on the side of the teacher-initiated and directed investigation.

Such skills may be taught using a wide range of activities. For any topic area, some sort of interesting item can be used to “grab” the pupils’ attention and allow them to start asking questions, and can even be made the basis of an investigation. The following have been used as starting points for special needs pupils for acquiring the process skills of observing, predicting communication, finding out and so on:

o Objects which are unusual but relevant to the topics being taught, such as suitable artefacts, to stimulate questions and discussion, or working, moving or mechanical models. The teacher draws out of the pupils their theories or good ideas (hypotheses) about what is happening as the exercise goes on. In this way children can develop the skills of observation, effective questioning, predicting and hypothesising.

o An interesting story related to the topic being covered. The situation is non-threatening and pupils soon become involved in predicting “What happens next?”, and can take turns to complete the next sentence in a “fortunately . . . unfortunately” sequence. Creativity and communication skills can be developed.

Curiosity can help pupils to make a real hypothesis about the situation, but if this a novel method for them it will need to be introduced carefully and nurtured.

Please Miss, what’s that?

Here is an example of a stimulus experiment. Pupils enter the room and see a tall jar with raisins rising and falling in it. But why? How?

Take a tall clear glass jar of water and add one tablespoon of bicarbonate of soda. Do not stir: allow it to settle. Add half a tablespoon of mixed fruit or raisins so that they fall on top of the bicarb. Just before the pupils arrive, add enough vinegar (preferably colourless, about two tablespoons) to start the mixture gently fizzing. Remember not to stir; you can always add some more later. The raisins - but not any of the other mixed fruit - start to float, then sink. The reaction continues for about three hours or until all the vinegar and bicarb solution has been used up. Later the other pieces of mixed fruit start to float.

The vocabulary used by the pupils to describe what they see and try to explain why is often quite creative. Many interesting things will be said which reveal much about the pupils’ level of understanding of concepts and scientific vocabulary.

Why does this happen? “Let’s find out” . . . let’s investigate the variables and see what happens in various controlled experiments with each of the materials alone or any two together.

The explanation is in the production of carbon dioxide bubbles which “stick” to all the fruit; the density of the raisins is such that when they have bubbles on them they float with the increased buoyancy of the bubbles. When the bubbles break as they reach the surface of the water the raisins sink again to the bottom. The chemical reaction need not be known, but it is the formation of carbon dioxide from sodium bicarbonate and any acid (dilute).

There is a link with the SC3 Materials topics of “types of reaction”, “acids” and so on and therefore scope for using this stimulus to begin an inquiry into the areas of chemical reactions.

Professor Alan Jones and Elaine Golding are at the department of chemistry and physics at Nottingham Trent University.