Illuminating science

2nd May 2003 at 01:00
The revised science SATs for key stage 2 are almost upon us. John Stringer looks at the importance of accurately recording investigations and how literacy skills can boost pupils' efforts

In this year's science tests, children will be asked what an activity is designed to find out, and how it might be carried out. They will need to identify the factors they are changing and what they are observing or measuring, and what factors they need to control to ensure a fair test. They will be asked if it is possible to predict outcomes. They will need to know how to present and interpret results, and whether the results match the prediction. They will need to evaluate how good their evidence is, how it might be improved, and whether it supports any prediction.

This project examines how and why scientists make records of their predictions and tests. Getting pupils to understand that what may seem to be a repetitive task has actually been an important part of charting many past - and present - scientific discoveries may help them approach this area of the subject with a greater understanding.

So how's this for the record of a science investigation: "In a very dark chamber, at a round hole, about one third part of an inch broad, made in the shutter of a window, I placed a glass prism, whereby the beam of the sun's light, which came in at that hole, might be refracted upwards towards the opposite wall of the chamber and there form a coloured image of the sun."

So far so good. Too many commas for my liking, but I think I could follow the instructions and duplicate the investigation. But what did this scientist discover? Can I follow his results and do I agree with his conclusions?

He concluded that white light is a mixture of rays of light of every colour, and that each colour bends to a different angle - red being the least bendable, then "orange, yellow, green, blue, indigo and deep violet".

By now you will have concluded this is no Year 3 investigation into light and shadows; this is from Isaac Newton's Optics, published in 1704.

So how would Isaac fare in the SATs? The standard assessments in science are now focused more on the skills of science and less on the content. The use of language is a vital skill. It's no use having the answers if you can't put them down; and we owe it to children to ensure that they demonstrate their understanding as clearly as possible. Isaac has not made it clear what his activity is designed to find out, nor has he made a prediction; perhaps he was away that day. But it is clear what he is changing, and what he plans to observe.

He goes on: "All white, red, yellow, green, blue, violet bodies ... in red homogeneal light appeared totally red, in blue light totally blue, in green light totally green, and so of other colours. In the homogeneal light of any colour they appeared totally of that same colour. I never yet found any body, which by reflecting homogeneal light could sensibly change its colour. From all of which it is manifest that if the sun's light consisted of one sort of rays, there would be but one colour in the whole world."

What's this word "homogeneal?" Oh, it means single colour. Why not say so? Keep it simple. Always remember to "communicate in appropriate scientific language". Newton's results are impressive, though I think he is pushing his luck by making universal generalisations after just one try. "I'd like to see you do that again, Isaac, after play."

Quite nice though. Conclusions "related to scientific knowledge and understanding". At least a level 4. And a bit of prediction too. A one-colour world ? Tough. "Maybe you could make one after play in design and technology."

We have no idea whether Newton found recording discoveries as much of a drag as many children do. But the fact is that writing something up is never as much fun as doing it; and while it can never compare with inflating a rubber glove with carbon dioxide, melting a "hand" made of ice or exploding a balloon filled with paper "seeds" - to name just a few of my recent teaching activities - it has a purpose, or to be strictly accurate, one of three purposes.

Why make a record?

Scientists record for their own sakes. Their initial scribbles may be, in the true sense, an aide-memoire. It's essential to record what actually happened because, unless you keep a record, how can you possibly begin to see a pattern? And how can you do the same investigation again?

Remember, repeatability is the essence of science. This kind of personal recording can be untidy, back of the envelope stuff, or it can be a computer record of results over a period of time - the concertina of print-out that pours from a computer as a radio telescope scans the heavens. Either way, it's not for public consumption. The most important thing is that it is recorded accurately and honestly, whether or not it matches the scientist's original prediction.

Private scribbles can also be revealing about a historical person's life.

Newton, apparently so arrogant and confident in public, is shown by his private notebooks to be both uncertain and capable of true wonder at his discoveries: "I have often with Admiration beheld, that all the Colours of the Prisme being made to converge, and thereby to be again mixed, reproduced light, intirely and perfectly white."

Writing for a wider audience

Scientists also write for their peers. At this level, they are aiming to convince colleagues of the reliability of their discoveries and, incidentally, to lay them open to the criticism and questioning of other scientists. Understandably, they write much more carefully. Like an Office for Standards in Education report, every statement must be backed by evidence. Here, tables can be converted to graphs, which clearly demonstrate patterns and trends. Arguments are set out logically, rather in the "observations, results, conclusions" form we may recall from our own schooldays.

This kind of recording is reflected in the national curriculum - "use their scientific knowledge and understanding to explain observations, measurements and other data or conclusions".

Scientists also record to report to others; funding bodies, professional organisations, and the media ("Y3 Pupils claim Moon made of Wensleydale").

Here the evidence must still be sound but the style can be more accessible, as for the assembly presentation, the parents' science evening, and the letter to the supermarket company complaining about the strength of their carrier bags.

Writing frames and scaffolding

However children write, we do them little service by presenting them with a blank sheet of paper. Its intimidating whiteness is not conducive to recording science discoveries. There are other ways of recording science - cartoons and poetry among them - but if we are aiming for a structured report, then we can borrow a well-constructed leaf from the literacy curriculum. Writing frames (see page 22) are outlines which support children's writing. They have been compared with scaffolding. Like scaffolding, they are in place during the construction of a piece of writing and they are removed at the end, leaving no trace of their use.

Writing frames give children a structure to concentrate on communicating what they want to say, rather than getting lost in the form.

David Wray and Maureen Lewis have identified a number of circumstances in which a writing frame is useful. For teachers of science, it may come into its own:

* when a group of children are stuck in a particular form of writing;

* when children are uncertain what style they are writing in; for example, personal or instructional;

* when children use the wrong style altogether. Persuasive writing needs evidence to supported it. Instructions are different from reports; they should not be presented in report form.

David Wray and Maureen Lewis's model leads from demonstration (teacher modelling), to collaborative writing (for which a word processor can be useful), to scaffolding (writing supported by frames) and finally to independent writing.

White light and prisms

So how did young Isaac get on with his experiment with a prism and a hole scratched in the shutter? There have been explanations of coloured light since the time of Aristotle. He'll need some pretty good evidence to counter 2,000 years of accepted views. Well, the white light goes into a triangular prism and is made darker by the thin edge near the window - to red. At the other, thick end of the prism, it is made much darker and comes out blue. Simple!

But Newton also noticed the light through the hole in the shutter came in as a circle; but it left the prism as a multicoloured strip. So, he concluded, the light is not "changed", it is physically split. His investigation confirmed for him that the spectrum was created by the fanning out of the colours in white light. All he has to do now is convince his peers.

Very nice, Isaac. Here's a star and a smiley face. But if you want a level 5, never mind persuading the president of the Royal Society, you'll need to do more than that: "When any sort of Rays hath been well parted from those of other kinds, it hath afterwards obstinately retained its colour, notwithstanding my utmost endeavours to change it."

Newton found that coloured light stayed coloured - red stayed red, blue stayed blue.But he then went further. He recombined the colours of light using a second prism, and the resulting light was white. If the light had been changed by being transmitted through glass, then the second prism should have turned one colour to another again - red to blue, blue to green, perhaps. But it didn't. It bent the colours together again into one white ray.

Last word to Newton

"Hence therefore it comes to pass, that Whiteness is the usual colour of light; for, light is a confused aggregate of Rays indued with all sorts of Colors, as they are promiscuously darted from the various parts of luminous bodies." Collapse of all opposition. Game, set and match to Isaac.

Curriculum links

The English curriculum asks that pupils "plan, draft, revise, proof-read, present and evaluate their own and others' writing". "They should choose form and content to suit a particular purpose."

Links to QCA schemes of work

Key stage 1

* Sc1: 1a making observations and measurements when trying to answer a question

* 2d recognise when a test or comparison is unfair

* 3g communicate what happened in a variety of ways.

Key stage 2

* Sc1: 1a establish the links between causes and effects

* 2d changing one factor and observing or measuring the effect while keeping other factors the same

* 2f make systematic observations and measurements

* 2h communicate data in an appropriate and systematic manner.

Sources and resources

Writing Frames by David Wray and Maureen Lewis. PCET, 27 Kirchen Road, London W13 0UD (pound;24.99) Making Sense of Primary Science Investigations, by Anne Goldsworthy and Rosemary Feasey, revised by Stuart Ball, Association for Science Education (pound;10). Tel: 01707 283000

The Faber Book of Science edited by John Carey (pound;9.99), The Ascent of Man by Jacob Bronowski (BBC 1973)

John Stringer is a writer of New Star Science (Ginn) and series editor of Heinemann Explore Science, both primary projects


What I want to find out; the link between x and y:

What I am changing (x):

What I am observing or measuring (y):

I am changing x to see what happens to y. So my question is: If I change x, what will happen to y?:

What I am keeping the same. I must do this, for fairness:

Here are my results as a table:

Decision time!

* If both x and y are in words, I cannot draw a graph.

* If x is in words but y is in figures, I can draw a bar chart.

* If x is in figures and y is in words, I can draw a bar chart - but it will not be very accurate.

* If both x and y are in figures, I can draw a line graph.

I must put the change on the horizontal x axis of the graph, and the measurement on the vertical y axis. My graph is on squared graph paper.

What did we find out?

* I found that changing x made this difference to y:

* I think this was because:

* I think my results were accurate because:

* I think I could do this better by:

* If I did this again I would:

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