Halloween used to be a poor relation of Guy Fawkes Night. Bobbing for apples and carving lanterns out of turnips were fun in their way, but the real excitement came a week later. Recently, though, Halloween has become much more popular - it is, after all, a major party day at Hogwarts School of Witchcraft and Wizardry - and a great deal more commercial.

The shops are full of orange and black decorations, masks, plastic cauldrons and ghoulish sweets. Many children will be making pumpkin lanterns at home and going to Halloween parties.

But of all the festivals in our multicultural calendar, Halloween is the hardest to use as the basis for any sort of positive teaching. Apart from the sheer glee of being revolting - something close to the heart of many children - what is the point of all the ghoulishness? Why is it traditional to want to be frightened at Halloween?

The activities suggested here are a simple, constructive way of joining in the fun. Recognising Halloween in the classroom gives an opportunity to explain the traditions that lie behind its puzzling, sometimes frightening rituals.

Halloween is one of our oldest festivals, dating back over 2,000 years to the Celtic celebration of Samhain. This marked the end of the growing year, when the last of the herds returned from their summer pasture, and the gathering of the last harvest. But it was also the time when the barriers between the natural and supernatural worlds were suspended and dark forces unleashed. This is the origin of Halloween’s macabre associations.

It was a frightening time, when the spirits of the dead were thought to revisit their homes, and the gods played nasty tricks. The Celts made sacrifices to appease the gods, and the Anglo-Saxons lit bonfires to ward off evil spirits.

People took advantage of the accessibility of the spirit world to try to foretell the future. Even today the tradition persists that if you look in a mirror on Halloween, the face of your future spouse will appear behind you.

Halloween’s name is more recent than the festival itself. “Hallow” means holy. All Hallows Eve was the night before All Hallows, or All Saints’ Day, on November 1. Since the 8th century this has been the day when Christians honour all the saints. But in spite of its Christian label, Halloween remained the day when gosts, goblins, witches and all other such traffickers with the supernatural world were thought to be active.

This is why some religious groups disapprove when schools treat Halloween as entertainment.

The origins of Halloween jack-o’-lanterns are hard to trace. In Britain they used to be made from swedes, but the pumpkin, apart from being a more festive colour, is also better adapted to the purpose, as it is already hollow. Pumpkin lanterns came to Britain from the US, as did another, more controversial ritual.

“Trick or treating” involves dressing up and knocking on doors to ask for a “treat”, usually sweets. If the treat is refused, a “trick”, usually not very serious, will be played. But many adults have doubts about encouraging children to knock on doors and ask for presents.

So how can teachers put a positive spin on what is really a celebration of superstition, in danger of being hijacked by consumerism? Given the reported increase in young people’s interest in the occult, teachers might want to take the opportunity to discuss children’s perceptions and fears about the supernatural.

With younger children, it might be useful to stress that the ghoulishness of Halloween is “just pretend”. Even very young children understand the idea that up to a point, it is fun to be frightened.

Another way in which schools can help give a positive point to Halloween (and make trick or treating more altruistic), is to use it as an opportunity for fundraising.

This is common in the US, where Halloween is a fundraising day for UNICEF, the United Nations’ children’s charity, but over here, UNICEF has avoided endorsing trick or treating.

However, this year it has launched Pumpkin Week, a fundraising project to run in the first week of November. For an activity pack, phone UNICEF’s helpline on 0870 606 3377.

School activities might include scary cake bakes, fancy dress parades or a day when children (and staff!) pay 50p to come to school in their scariest outfit.

If children go out collecting in fancy dress, they could use pumpkins as collecting boxes or make festive ones by decorating buckets with orange crepe paper, and learn through role play how to explain what they are collecting for and why. Children should always be accompanied by an adult.

Activities and images from The Halloween Book, left, by Jane Bull, published by Dorling Kindersley, pound;5.99.