Subject: Temp of ice before and after adding salt...

I am working on a project with a thrid grade class.  The students had a 
cup that contained a small amount (say 1/4 cup) of ice chips and measured 
the tempurature of the ice.  The readings of the students varied between 
40 and 33 degrees F.  After the addition of the salt, the temperatures 
drastically decreased.  On my own sample, before the salt the temp was 32 
degrees F and after the salt was added, the temp I recorded was 20 degrees 
F.  How can one explain the decrease in the overall temperature of the 
solution?

Re: Temp of ice before and after adding salt...