Really?
It’s an awful lot of toast, but then a typical lightning bolt isn’t short on energy with over five billion Joules. This means that one typical strike could power a 1000 Watt, two slice toaster for 84,000 minutes in which time you could make around 100,000 slices of toast.
Static build up
Thunderstorms are an amazing natural spectacle, but even more amazing is the fact that we still don’t totally understand the processes which create lightning. What we do know is that lightning is a discharge of the static electricity that builds up in clouds in certain weather conditions. You’ve probably noticed that thunderstorms often happen on summer afternoons when the ground is warm and the air is humid. As the warm, humid air rises and meets cooler conditions higher up, water condenses out of the air to form clouds. The condensed water droplets then start to fall and collide with the warm air that is still rising.
All these little collisions give the water droplets a charge and for some, as yet unknown, reason the positively charged droplets find their way to the top of the cloud whilst the negatively charged droplets fall to the bottom. This separation of charge creates an electric field within the cloud which grows stronger as the charges build up and induces a positive charge in the ground directly below the cloud.
Zigzagged
Air is normally a very good electrical insulator, but when the electric field becomes strong enough it ionises the air, separating it into negative and positive ions, and producing a conductive path between the cloud and ground. But the ionisation of the air isn’t uniform and zigzagged ‘step leaders’ start to appear from the cloud following the various conductive paths. At the same time positive streamers start reaching up from the ground, waiting for the step leaders to connect to them. Once a complete path is formed, there’s a deafening crack and the lightning reaches the ground.
With five billion Joules of electrical energy being discharged, the surrounding air becomes hotter than the surface of the Sun. We see this as a white flash and hear it as rumbles of thunder as the air rapidly expands.
What happens when lightning hits?
You have to be quite unlucky to be killed by lightning – only about 10% of the people hit each year die – but being struck by lightning is a far from pleasant experience as Roy Sullivan can attest. A park ranger, he was struck seven times between 1942 and 1977 and suffered a range of disabling injuries. Lightning strikes can blow your clothes and shoes off as the moisture on your skin rapidly boils and turns to steam. Any objects touching your skin will cause serious burns and you also risk hearing loss, seizures, headaches and blindness.
So if you find yourself outside during a thunderstorm, what should you do? The best idea is to head straight for your car. This might sound odd since cars are made of metal and are therefore very good conductors, but they are also Faraday cages. Faraday cages work on the principle that electric fields can’t exist within a conductor and so any charge remains on the surface. In the case of a car, or for that matter an aeroplane, lightning strikes will be conducted around the outside, leaving all the occupants safe from harm. This is just as well since on average aeroplanes are struck by lightning once a year.
Lightning isn’t just a devastating force, it can also create beauty. Lightning that strikes sandy beaches can make the grains of sand fuse together like glass, producing tunnel shaped shards of a material called Fulgurite. These shards are extremely rare and can come in different colours depending on the type of sand.
Is static in your clothes dangerous?
The crackles and sparks of static electricity that accompany taking off clothes made of man-made fibres can be pretty impressive, but they’re rarely life threatening. The amount of static that builds up on your clothes depends on the material and how dry the atmosphere is.
All fabrics have some tendency to build up a static charge, but synthetics like nylon, polyester and acrylic are particularly good at generating, and then holding on to, static charge. But whatever your clothes are made out of, nor how much you rub different layers together, if the air is humid the static charge will leak away into the atmosphere.
You can imagine that the Australian man who reportedly managed to burn a carpet as he walked over it, wished that it had been a rainy day or that he’d rethought his outfit. The story goes that he was wearing his best nylon jacket and woollen shirt for a job interview and as he walked into the building, the carpet beneath his feet started to scorch and make loud crackling noises. The fire brigade was called and when they finally tracked down the sparking candidate, they found he had 40,000 Volts across him. It just shows, it’s important to be well dressed for an interview.
Could you power a city with lightning?
In Back to the Future, Doc Brown uses lightning to power the De Lorean sports car time machine so that Marty can return to 1985. But could lightning ever be harnessed as a useable power source in the future?
At first sight it appears promising because a lightning bolt, which has over five billion Joules of energy, which could provide one household with all their energy needs for a month. However, Doc Brown had an unbeatable advantage over us – he knew when and where the lightning was going to strike.
In the UK we experience relatively few thunderstorms each year: in England thunder occurs on average 11 days per year, with even fewer in Scotland and Wales. Even during a thunderstorm it’s incredibly difficult to predict when and where lightning will strike.
Assuming that you are lucky and get a lightning bolt to hit your conductor, there would be major difficulties in storing the energy and then converting it to alternating current so it can run your appliances. In addition, any solution to these problems would need to be able to withstand the enormous surges in energy generated by each strike.
Finally, much of the lightning bolt’s energy goes into heating the surrounding air to temperatures greater than the surface of the Sun. So even if you managed to overcome the problems of collecting, storing and converting the energy from the lightning to make it useful, you would still only be harnessing a small proportion of the lightning bolt’s power.
It’s an awful lot of toast, but then a typical lightning bolt isn’t short on energy with over five billion Joules. This means that one typical strike could power a 1000 Watt, two slice toaster for 84,000 minutes in which time you could make around 100,000 slices of toast.
Static build up
Thunderstorms are an amazing natural spectacle, but even more amazing is the fact that we still don’t totally understand the processes which create lightning. What we do know is that lightning is a discharge of the static electricity that builds up in clouds in certain weather conditions. You’ve probably noticed that thunderstorms often happen on summer afternoons when the ground is warm and the air is humid. As the warm, humid air rises and meets cooler conditions higher up, water condenses out of the air to form clouds. The condensed water droplets then start to fall and collide with the warm air that is still rising.
All these little collisions give the water droplets a charge and for some, as yet unknown, reason the positively charged droplets find their way to the top of the cloud whilst the negatively charged droplets fall to the bottom. This separation of charge creates an electric field within the cloud which grows stronger as the charges build up and induces a positive charge in the ground directly below the cloud.
Zigzagged
Air is normally a very good electrical insulator, but when the electric field becomes strong enough it ionises the air, separating it into negative and positive ions, and producing a conductive path between the cloud and ground. But the ionisation of the air isn’t uniform and zigzagged ‘step leaders’ start to appear from the cloud following the various conductive paths. At the same time positive streamers start reaching up from the ground, waiting for the step leaders to connect to them. Once a complete path is formed, there’s a deafening crack and the lightning reaches the ground.
With five billion Joules of electrical energy being discharged, the surrounding air becomes hotter than the surface of the Sun. We see this as a white flash and hear it as rumbles of thunder as the air rapidly expands.
What happens when lightning hits?
You have to be quite unlucky to be killed by lightning – only about 10% of the people hit each year die – but being struck by lightning is a far from pleasant experience as Roy Sullivan can attest. A park ranger, he was struck seven times between 1942 and 1977 and suffered a range of disabling injuries. Lightning strikes can blow your clothes and shoes off as the moisture on your skin rapidly boils and turns to steam. Any objects touching your skin will cause serious burns and you also risk hearing loss, seizures, headaches and blindness.
So if you find yourself outside during a thunderstorm, what should you do? The best idea is to head straight for your car. This might sound odd since cars are made of metal and are therefore very good conductors, but they are also Faraday cages. Faraday cages work on the principle that electric fields can’t exist within a conductor and so any charge remains on the surface. In the case of a car, or for that matter an aeroplane, lightning strikes will be conducted around the outside, leaving all the occupants safe from harm. This is just as well since on average aeroplanes are struck by lightning once a year.
Lightning isn’t just a devastating force, it can also create beauty. Lightning that strikes sandy beaches can make the grains of sand fuse together like glass, producing tunnel shaped shards of a material called Fulgurite. These shards are extremely rare and can come in different colours depending on the type of sand.
Is static in your clothes dangerous?
The crackles and sparks of static electricity that accompany taking off clothes made of man-made fibres can be pretty impressive, but they’re rarely life threatening. The amount of static that builds up on your clothes depends on the material and how dry the atmosphere is.
All fabrics have some tendency to build up a static charge, but synthetics like nylon, polyester and acrylic are particularly good at generating, and then holding on to, static charge. But whatever your clothes are made out of, nor how much you rub different layers together, if the air is humid the static charge will leak away into the atmosphere.
You can imagine that the Australian man who reportedly managed to burn a carpet as he walked over it, wished that it had been a rainy day or that he’d rethought his outfit. The story goes that he was wearing his best nylon jacket and woollen shirt for a job interview and as he walked into the building, the carpet beneath his feet started to scorch and make loud crackling noises. The fire brigade was called and when they finally tracked down the sparking candidate, they found he had 40,000 Volts across him. It just shows, it’s important to be well dressed for an interview.
Could you power a city with lightning?
In Back to the Future, Doc Brown uses lightning to power the De Lorean sports car time machine so that Marty can return to 1985. But could lightning ever be harnessed as a useable power source in the future?
At first sight it appears promising because a lightning bolt, which has over five billion Joules of energy, which could provide one household with all their energy needs for a month. However, Doc Brown had an unbeatable advantage over us – he knew when and where the lightning was going to strike.
In the UK we experience relatively few thunderstorms each year: in England thunder occurs on average 11 days per year, with even fewer in Scotland and Wales. Even during a thunderstorm it’s incredibly difficult to predict when and where lightning will strike.
Assuming that you are lucky and get a lightning bolt to hit your conductor, there would be major difficulties in storing the energy and then converting it to alternating current so it can run your appliances. In addition, any solution to these problems would need to be able to withstand the enormous surges in energy generated by each strike.
Finally, much of the lightning bolt’s energy goes into heating the surrounding air to temperatures greater than the surface of the Sun. So even if you managed to overcome the problems of collecting, storing and converting the energy from the lightning to make it useful, you would still only be harnessing a small proportion of the lightning bolt’s power.
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