For many of us, the nature table is an abiding memory of early schooldays. It reflected the changing seasons - daffodils in spring, conkers in the autumn. Time passed slowly when we were young, and the seasons seemed defined by our clothes - summer frocks one day, buttoned coats the next. When your life is short and your experience of the seasons is limited, it’s the festivals that mark the passing year. Recent research has confirmed that young children find the changing seasons hard to grasp. Some confuse cause and effect - they believe that it gets colder because leaves fall from the trees, or clouds cover the Sun. Others believe that the Sun must be further away in the winter - though if that were the case, wouldn’t it affect the whole planet? Why are Australians celebrating Christmas on the beach?

Children can be shown that the reason the temperature changes with the seasons is more complex than that. It all stems from the angle at which our part of the world faces the Sun. If you want (perhaps unwisely) to get an even tan, it’s no good standing in the Sun. You will end up burning your shoulders, insteps and the tops of your ears. These are the bits that are at right angles to the Sun. To tan, you lie down - a little like toasting a crumpet.

You hold a crumpet - or your skin - parallel to the heat for an even finish. And the same goes for countries. When the UK is at right angles to the Sun, we feel its greatest heat. But as the Earth makes its annual journey round the Sun, we are tipped away from the Sun’s rays, and they hit us obliquely. As we move into winter, the Sun is lower in our sky than it is in summer. Like a torch beam spread across a wall, the Sun’s light and heat is scattered more widely, and the mornings get colder, the evenings darker, and the daylight hours shorten.

These seasonal changes affect the life around us. At this time of year, deciduous trees lose their leaves - packed with waste products that stain them brown - and reduce their activity for the winter. As plant food becomes scarce, some birds migrate to warmer countries and richer pickings. Some mammals hibernate, and insects of all kinds change into forms - eggs or pupae - that are resistant to cold. Fortunately for fish and other water life, ponds freeze from the top and ice floats. They carry on their lives in the freezing water below - at a slower pace.

People like change and novelty, but they also like security and the familiar. Cycles answer these paradoxical needs to perfection. The seasons change as the year passes, but the progress is predictable and reassuring.

* Don’t miss our second RSPCA poster on the seasons. See centre pull-out MARKING THE SEASONS

* Are trees really alive? Tape a card frame to a window that overlooks a deciduous tree. Ask your children to draw your adopted tree from time to time, date their pictures and collect them in an album. Over the year, they will record the seasonal changes in the tree.

zWhich birds stay with us through the winter? Between autumn and Easter, put appropriate food on a bird table, or hang it from a tree. Record the birds that visit your feeding station, dating your record. How do the species change?

* Use a digital camera, pictures and sound recordings to log seasonal change. Ask children to list the day-to day changes they see, recording firsts - the first butterfly, the first conker, the first house martins.