John Stringer shows ways to develop the skill of observation
Scientific enquiry involves making careful observations. Sometimes observations have to be made over a short or a long time. In this project, we use photographs that expand or shrink that time, allowing us to view changes that would otherwise pass almost unnoticed. You can use them as starting points for discussions and activities.
Here, water drops from a leaf tip. Heavy rain could drag down or even snap a leaf off the main plant. Children can see that many leaves are waxy and shaped to form and release drops of water.
THE CHANGING SEASONS
When you are young, the year stretches out for ever, and the seasons change with creeping slowness. Summer holiday memories seem distant in January. It feels to children as if the world has always been cold and dark.
Trees change with the seasons. These changes are slow - they may pass unnoticed. As a result it's easy to believe that trees are lifeless. But pictures such as these - showing the same scene in four seasons - remind us of the natural changes that take place throughout the year.
As you name the seasons and look for changes in the trees and landscape, you can imagine the cycle of change, as one year grows old and a new year bursts with life.
* THINGS TO DO
Tape a picture frame made from card to a window that looks out on a natural area - a garden, a field, a wild area or, best of all, a tree. Ask pupils to sketch the scene through the frame at different times of the year. Date their pictures and put them in a book or on the wall in date order.
Flicking through the book or looking at the display illustrates the changes through the year.
Immediately, an apparently unchanging tree becomes alive and full of variety.
* THE CHANGING MOON
All through the month, the Moon's shape appears to change, but cloud cover and street lighting make this hard to see. The Moon has no light of its own. As it circles the Earth, we see it lit by the Sun from different angles. The changing light and shadow make it look as though its shape changes.
When the Sun, the Earth and the Moon are in line, with the Earth in the middle, the full Moon is brightly lit. It then shrinks and wanes every night until, two weeks later, only the glowing edge of the new Moon is visible. The three are again in line, but now with the Moon in the middle. The face we see then becomes more clearly lit each night, until the growing, waxing Moon becomes full again.
The Moon orbits the Earth every 28 days. As it orbits, it dips and bobs. It also spins once every 28 days in synchrony, so that we see the same face - the "Man in the Moon" - all the time. But the Moon has no permanent "dark side". When its face is reflecting little of the Sun's light to us, the distant side is in full sunlight.
A time-lapse picture, such as this, illustrates these phases. Look into the sky on winter nights and match your observations to the photograph.
THINGS TO DO
You need a shoebox, a soft ball, some dowel, black paint and a brush, scissors and a torch.
Make the model to demonstrate the phases of the Moon as shown in the diagram.
Fix the ball to the dowel and put the lid on the box. Switch on the torch and look through each peep-hole in turn. Imagine you are the Earth, the ball is the Moon and the torch is the Sun. Describe what the Moon looks like through each peep-hole and explain how the Moon can appear to take different shapes.
In ths model the Moon stays still while you, the Earth, move. What really happens?
CAPTURING THE MOMENT
Photography can record the fastest action and slow it to a crawl. We can then see the grace of an athlete in action as a series of images.
Movement is slowed and effort and control become clearer. A bullet strikes a glass at 450 metres per second, shattering it to pieces and allowing the wine held within to escape, but leaving the stem unbroken. A drop of milk falls on to a plate, producing a momentary coronet of droplets.
Watching events that occur at high speed means you may miss the moment. You would understand what makes one ball bounce higher than another if you saw each ball hit the ground, squash and recover its shape. A ball that regains its shape quickly retains its energy and bounces higher.
THINGS TO DO
Flick books illustrate body movements well. Draw stages of action on small pieces of stiff paper and staple them together. Giving the pages a slanting edge makes the flick effect smoother. Slow the action by either making pairs of identical pictures or by alternating blank pages with illustrated ones.
* TEACHER NOTES
Watch out, watch out...
Observation is one of the skills that children will develop through scientific enquiry. It is important in their studies of the natural world and of the heavens, where investigation is impractical or impossible. But it is not a skill to take for granted.
In many ways, children can be better observers than adults. Their eyesight may be sharper, they can give single-minded attention to things that really interest them, and they are willing to bend and crawl to get closer to the subject of their observations.
In other ways, however, the skills of children need focusing. They may be easily distracted, pay more attention to the irrelevant or the unimportant, or miss the true purpose of their observations. Observing and recording over a period of time - the growth of a bean plant, the behaviour of woodlice, the changes in the Moon - will help develop these skills.
Observation aids A hand-held lens or magnifying glass can enhance observation. If children bend over it and the object of their interest, they put both in shadow. If possible, they should stand upright, holding their subject in one hand and the lens in the other. Bringing the lens to their eye should bring their observation into focus.
Binocular microscopes can show a forest in a clump of moss, a desert in a hand. They are easy to use and give a clear picture when they are turned to the window or a lamp - the microscope's pillar pointing towards the child. A binocular microscope can show you a living creature in a transparent pot, pond animals in a beaker of water. Great magnification is not important. In fact, you can lose a lot by over-magnifying and seeing a few hairs on the caterpillar's back, rather than its legs and head.
Binoculars for long-distance observation should not be too powerful - what you gain in magnification, you lose through shake. Use the straps to avoid breakage. Children will observe best by setting the eyepieces to their own eyes before they start. Get them to sight their target along the top of the binoculars, then lift the binoculars between their eyes and what they are looking at.
Digital cameras make it possible to display a series of pictures as a moving image (such as growing plants or crystals), and to collapse time, so that changes can be seen more clearly.