Science Questions

Would you feel lightning strike a house?

Sun, 9th May 2010

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Tara Elliott asked:

I was woken up last night by the loud sound of thunder and I swear that I felt the house shake. We live on the top floor of a condo complex. Is it possible to feel lightning strike the house?†


Dave -  Lightning is basically a huge spark.  You get about 100,000 Amps of current flowing down through the air.  This gives out about a thousand trillion Watts for about 30 millionths of a second, so the total amount of energy released is about 30 mega Joules of energy.  Thatís very roughly similar to a 30-kilogram bomb.

Chris -   It depends on what the bomb is made of, doesnít it?

Dave -   Yes, but itís similar of order of magnitude.  Quite a lot of that energy is going to be a long way up into the sky though.  So basically, that energy is equivalent of about a kilogram of, say, TNT going off near your house.  Most of that energy goes into heating up the air and it gets very, very hot.  When hot air expands, that creates a shockwave of air pushing outwards and thatís what you hear as a thunder.  If that happens very, very close to you, then you will actually get quite a large overpressure, like a bomb going off, and if a bomb can shake your house, then a lightning strike should be able to.

Chris -   I did some back of the envelope calculations.  I think itís 120,000 pieces of toast you could make with the energy in one lightning bolt, assuming you could turn all of it into toast, obviously.  So thatís really quite a lot, isnít it?

Dave -   For the time period, certainly, yes.


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Tara Elliott asked the Naked Scientists: Hi, I was woken up last night by the loud sound of thunder and I swear that I felt the house shake.†† We live on the top (third) floor of a condo complex with a courtyard in the back. Is it possible to feel lightning strike the house?† It wasn't like the walls were shaking continuously or something, just a couple seconds worth of movement.† My husband does not believe me since he slept through this.† He swears I was dreaming.† Stupid question? Thanks! Tara Elliott What do you think? Tara Elliott , Thu, 6th May 2010

Could it have been an earthquake?  My sister-in-law woke up in exactly same scenario and my brother slept throughout - when they switched the local news on in the evening it turned out to have been an earthquake.  This might be ordinary in some parts of the world, but this was in Leeds, Yorkshire!

have a look at this website at edinburgh university and see if you were near any of these when you got woken up.

Matthew imatfaal, Thu, 6th May 2010

Once when I was at work, lightning struck a nearby building and the thunder shook our building. I am sure you would feel it if it stuck the building you were in. Bored chemist, Thu, 6th May 2010

The air pressure wave created by the lightning is quite large. It might actually be worse if it does not strike the builing you are in, but strikes something near by.

I was lying in bed one day when lightning struck the house across the street (and set it on fire). I'm pretty sure our entire house shook. Geezer, Thu, 6th May 2010

Thanks everyone!  Matthew- thanks for directing me to that website.  I looked, and it definitely was not an earthquake.  People were talking about how bad the thunder/lightning was the next day, so I assume that is what I felt.  I had no idea it could actually shake the building like that!  Not sure if it actually struck our building or something near by, but either way, I was not dreaming.  Thanks again!  Tara Elliott , Sat, 8th May 2010

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