Co-op Week Nine {Storms}

This week we talked about thunderstorms in our co-op weather class, and I had hoped to touch a bit on tornadoes and hurricanes as well, depending on our time.  However, I think we must have started class late because there was not even close to enough time. No matter - next week I am planning a "catch-up" week to do some extra things, and anything we didn't have time for in previous classes, so we'll do the tornadoes then.



1.  Thunderstorms are rain storms with huge clouds, strong winds, and LOTS of precipitation.  They form along weather fronts, often on hot summer days.  (in the tropics, it happens throughout the year).  Worldwide there are 40,000-50,000 each day.    I wonder where they are??  Because that is a lot of thunderstorms.  I found that info in a couple of books and also here.  Thunderhead clouds are cumulonimbus clouds that can be 70,000 feet (or 11 miles!) high. 



2.  Lightning and thunder - inside those huge clouds, the air moves up and down quickly and water vapor condenses.  All that motion causes the electrically charged particles - ions - to form electrical fields within the clouds.  When the fields become large enough, a "spark" can flash between them, which we see as lightning.    Lightning can occur cloud to ground, or between clouds.  Thunder is the sound that "spark" of lightning makes - it's really a sonic shock wave, produced by the air being super-heated by the lightning bolt.



3.  We tried a demonstration to produce some static electricity sparks and have sort of a visual idea of how this happens.  All kids know that sometimes when you get under a blanket, there will be static sparks; they know that if you rub a balloon on your hair you can stick it to a wall; and most of them enjoy the evil pleasure of shuffling across a carpet in order to "spark" their sister or brother.   We combined some of those ideas into this:  use a styrofoam plate as an "electron collector" and an aluminum pie tin as the "conductor"  You'll need to fashion a handle for the pie tin - we did it with masking tape and a piece cut off the styrofoam plate.  Basically, you need to be able to pick up the pie tin without your hand coming in contact with the metal.  Take the styrofoam plate and rub the bottom of it on your hair for a minute.  Set it on the table, bottom up.  Using the handle, drop the pie tin onto the plate and then slowly touch your finger to the edge of the pie tin.  It didn't work every single time, but we were able to get some sparks.  The explanation and the original instructions were found at the Science Explorer website - I've found some very fun science demos and experiments there, but this one wasn't one of the most dramatic.  LOL



4.  Lightning changes nitrogen in the air to nitrous oxide, which is good for plants!