Friday, October 1, 2010

Lab Quote Friday #5

I just have a couple of quick quotes from this week.  Part of lab this week involved a lot of fire because we were doing flame tests.  This is one of the students' favorite labs because we get to turn lights off and see pretty colors.  For those of you who don't know about this (I certainly didn't), here's a 3 sentence lesson from our lab book:
"When electrons absorb specific amounts of energy, they can attain higher energy levels.  In order to return to the lower, more stable energy levels, electrons release energy.  If the energy released corresponds to an energy of visible light, the emission produces a color that can be detected by the human eye." 
So basically, I make some solutions and the students dip a piece of wire in them and then stick the wire into a flame.  Before the wire causes an orange flame, they should see another flame produced as the solution is burned.  This flame can be any color of the rainbow (including orange) depending on the element in solution and only lasts a couple of seconds.  Sounds like fun, right?  It is!
So with this lab, we get a LOT of "oooh"s and "ahhh"s.  We also hear, "It's blue!!  It's green!!  Oh, wow, it's red!!  Was that purple?"  It's all very exciting.
After the students test 8 different solutions, we give them 2 unknown solutions that are a mixture of 2 of the previous solutions.  They should see 2 colors before the orange flame.  One group was working on one of the unknown solutions.  It was a mixture of copper and calcium which produce green and red flames respectively.  One group shouted out "Ooooh, it's like CHRISTMAS!!"
A couple of the solutions just produce orange-ish flames, so it's hard to differentiate between the solution flame and the wire flame.  Either way, the students are seeing an orange flame, so they should assume that particular element is producing an orange color.  Instead, you hear comments like, "I don't see anything!" and "I guess it's just an invisible flame."  I ask them, "You don't see anything?"  They say, "Well, it's just orange."  Me: "Then write down orange!" 

1 comment:

ksstableford said...

I love your mascot -- the lab Lab.