Physics takes a turn in Oulu

We may live in a high tech city, but I never thought that Physics would go upside down here in Oulu.

Saturday was a rainy day. We had a few thunder showers and quite a bit of lightning. As Kannan was driving me near the Oulu river, I noticed a streak of lightning very close to us, and the reaction was not the usual fast dissipation of the lightning fork.

I wondered why that was.

I forgot the matter, although I did say in passing to Kannan that the lightning must have struck quite close to us.

In the evening, Unnop of the Pailin Restaurant rang me and said that the lightning had caused the his card swiping machine to burn out. Luckily, the service engineer came and fixed it. It was only then they knew that it was the transformer and not the machine that had been damaged.

When they looked around they did not seem to find any place the lightning had struck but they saw something most strange.

The birch tree next to the door of the adjacent department store was burnt from the bottom up causing the tree to split along the centre.

It was not as if the lightning had hit the tree at the top, but it had hit the ground, causing mud to be thrown out of the ground and the tree to be split the reverse way - upwards.

The tree had split right through. A close examination of the second picture will show the crack down the centre on the reverrse side to the burn.

When I reached home, Annikki had some interesting comments to read me from our local newspaper. It was reported that lightning had struck the ground in parking lot, travelled along a tarmac, crept into a car and thrown the plastic bumper away from the car and damaged the electricals in two adjacent cars. Also, the lightning had travelled along the tarmac and thrown up grass from the nearby lawn.

The weather expert had commented that although there has never been a case of anyone travelling in a car being hurt by lightning, he came to a conclusion that it was not due to the rubber tyres. He compared the case of the protection being provided by rubber boots when lightning strikes near a person wearing these boots.

Sadly, the weather man should have stuck to commenting on the weather and not about rubber technology. The two cases are vastly different.

Rubber shoes are insulators protecting a light charge from affecting the wearer. The tyres of a car have a high amount of carbon black, making it a conductive mass which ensures that any charge is dissipated to the ground. That is why people travelling in a car are not affected by lightning as the lightning tries to find the shortest way to dissipate the energy.

In this particular case, the conductive tyres permitted the charge to enter the car through the tyres and then blew off the insulating plastic which developed the opposite charge to the metal body which was charged by the lightning.

Physics certainly took a beating today in Oulu!