Flashy Fulminology

Are you a fulminologist?  A very flashy title for someone who studies lightning.  Lightning is an "atmospheric electrostatic discharge", a fancy way of saying it's a spark.  One very BIG spark!  Scientists know what it is, but exactly how and why it forms is still a matter for debate.  You've heard the saying 'water and electricity don't mix', but yet it is thought that the ice inside a cloud is a key element in forming lightning - that and perhaps a combination of wind, humidity, friction and atmospheric pressure.

Lightning can occur with either positive or negative polarity;  negative is more common, but positive lightning can carry ten times more current.  In either case, the amount of voltage depends on the length of the bolt - the longer the bolt, the higher the voltage.  Lightning can heat the surrounding air to thousands of degrees.  This causes the air to expand rapidly which generates a supersonic shock wave that as it dissipates becomes an acoustic wave we hear as thunder. 

We all know about cloud to ground lightning - the most dangerous kind.  One famous lightning hit was the Eiffel Tower in 1902.

Source:  Wikipedia

The top part of the Tower had to be reconstructed. 

And one of the most spectacular light shows in the sky is caused by cloud to cloud lightning.

Source:  Wikipedia

There is also intra-cloud lightning when there are both negative and positive charges within the same cloud.

As well, lightning can be produced by volcanic eruptions when rock, ice and ash particles collide and produce static charges, a phenomenon known as a 'dirty thunderstorm'.

Source:  Wikipedia

Lightning can be the cause of a great number of wildfires, but wildfires can also cause lightning by creating enough dust to produce a static charge, which in turn can start another wildfire.

While scientists are not really sure how lightning occurs in clouds, they can recreate it.  Or at least recreate how it looks to us.  Recently I visited Boston's Museum of Science and got to participate in their electricity show by being in a metal cage that was hit by 'lightning' demonstrating why you are safe in a car during a storm, although not a convertible or one made of fiberglass.  Click here to see a full explanation of why that is the case.  Here I am in "the cage" with a friend and the program presenter.

If you think "the cage" looks like a bird cage, you're right!  And here is a photo from the Museum's website of what the cage looks like when it's hit by lightning.

Source:  Museum of Science

When you're actually in the cage, you definitely don't get the full effect!

I got to go behind the scenes because I have a friend that works at the Museum of Science.  Thanks again, Aaron!  Hope you learned something about lightning.  I certainly did!  For a couple of videos to learn more, click here and here.  For a video about the phenomenon of ground to cloud lightning, click here.