When lightning hits the ocean why don’t all the fish die? This was my favourite question asked during Oxfordshire Science Festival.

It’s my favourite because it made all the scientists I spoke to think; it stumped some and was asked by a five-year-old! I also love lightning and am fascinated by the power and beauty of it zapping through our skies.

A few years back I was standing at the window of my first-floor flat looking out on the garden when suddenly a large tree exploded into pieces right in front of me.

It had been struck by lightning and by the time my heart returned to my chest it was a smouldering, splintered stump. It was the most spectacular thing I have ever seen and has completely ruined fireworks shows for me.

Lightning is one of those breathtakingly beautiful and frightening natural events that generate lots of questions. Can lightning ever strike the same place twice? Can you survive a lightning strike? Is that rubber thing true?

Sizzling science to the rescue! Let’s start by looking inside clouds. The water vapour and ice bouncing around inside clouds create electrical charges. This causes the cloud to act a bit like a giant fluffy battery where the top of the cloud is positively charged and the bottom is negatively charged.

This charge separation creates the lightning that you see splintering through clouds. A positive charge is created on the Earth’s surface, below the most intense point of the storm, that beckons like a lover’s hand reaching desperately for those negative charges at the base of a cloud.

A channel of charged air may break through the base of the cloud allowing the negative charge to seep into the air between the cloud and the ground. This “leader” rapidly spreads its fingers in a step-ladder formation reaching ever more desperately for the Earth.

About 1.4 billion times each year a finger of electricity will reach the earth in a spectacular lightning strike travelling at 300 million metres per second and five times hotter than the sun.

We all know that water conducts electricity (think hair dryer in the bath) so when lightning comes in contact with water the electricity will be conducted beautifully right? Well… sort of.

Water (sea or fresh) does conduct electricity but it looses its intensity quickly after contact. This means that the surface of the water will be highly charged but the further you move from the contact point the less intense the charge. If you are the unlucky sardine who happens to be hovering near the surface right at the point where a bolt strikes, you will be toast but your mates swimming say five metres down won’t be affected.

Moving from sardine to man. Lightning is HOT and electric.

The effect on your body from a direct strike will be catastrophic. It will interfere with the electric current that makes your heart beat, can melt muscles and damage cells. Side strikes are survivable but the long-term effects will be major. Oh, and that rubber sole thing... imagine throwing a shoe at the sun in the hope it will protect you.