Here's how it went. First, the kids put there hand in an empty plastic baggie and held it in a bowl of ice water. It didn't take long for them to feel the effect, but I timed them for 30 seconds, which was about the time it started to get rough for most of them. They rated how cold their hand felt on their experiment sheet.
Then, they put their other hand in my special "blubber bag" which consisted of two Crisco shortening filled baggies inside another baggie. The kids put their hands in between the two Crisco bags and stuck that in the ice water again for the same amount of time. They were pretty excited when they realized how well our "blubber" insulated their hands from the cold. They rated how cold their hand felt this time on their experiment sheet and practiced drawing conclusions about why arctic animals have blubber and how it helps them live in the tundra.
Other than the hubby telling the kids that the "blubber" came from liposuction patients, it all went swimmingly and the kids really enjoyed themselves! They already knew that arctic animals have blubber because it's one of our vocabulary words, but they got to experience its benefits firsthand, which really drove the information home. I so wish I had more time to do fun stuff like this!