King conkers

The quaint game of conkers involves hitting two nuts of the horse chestnut tree, each held on a piece of string, together until one is destroyed.

World Champions

Believe it or not, there is a world championship for conkers. It is held by the Ashton Conker Club in Northamptonshire, England. Their rules are a bit stricter than the playground version: you are assigned conkers (to stop cheats who have treated their conkers with chemicals or heat to harden them); you are given three attempts to hit the opponent's conker per go, and normal play is limited to five minutes, after which it's the best of nine hits – and this is where accuracy can be key.

Some well-known cheats for conkers to make them harder include baking them, soaking them in vinegar and even applying a coat of varnish. But as the 2005 women’s world champion Jayne Coddington said, "It's not necessarily about brute force. This year I played a gentleman from Venezuela in the first round and he was whacking my conker with such force he smashed his own."

While some competitors go for power, conkers also need to take the hits too. "In the final, my nut suffered a big crack and if my opponent’s conker hadn't split I was in danger of losing," says Jayne.

Soft landing

But the game of conkers is actually quite insightful into the world of collisions and how cycle helmets protect you.

Cycle helmets are made from expanded polystyrene, and their job is to compress as they are impacted. Too soft and the helmets will compress as far as they can, and then the force is then transferred to your skull. Compression also spreads out the impact over a longer time, which is less severe for the head.

Helmets are tested by dropping them on anvils and measuring the forces experienced inside the helmet. Although this isn’t entirely realistic to what a crash is like, it enables a standardised and repeatable test.

So perhaps those who treated their conkers had it wrong all along, and the perfect conkers is one that's not too soft and not too hard.

Further reading

The history of the cycle helmet - Bicycling magazine

The helmet than can save American football - Popsci

Helmets: how they work and what standards do - helmets.org

The folowing links are external