I just finished 2 days of 4th grade Geology camp, and now I can teach about glaciers in my sleep!
One of the really fun things I get to do is to demonstrate glacial action with the use of gummi bears and blue jello.
We are surrounded by glacial features in this glacier-carved valley, but few kids really understand geology because of the large time scale involved.
Around here there are many glacial erratic boulders, and there is one right near these kids' school that often gets painted by rival schools. Last week the rock was yellow, but this week it's blue!
When I ask the students if they have ever seen a glacial erratic boulder, they say "no", unaware how the yellow/blue rock got to where it is now -- what fun it is to tell them about how that rock got there -- this is the kind of thing that makes geology relevant to them. I love to be able to teach "hands-on" science, and the biggest praise I get is when a kid tell me after the lesson "I really get it now!"
For teachers out there -- here's what I do:
1) Before class, I built a mountain-valley landscape on a large tray, using crushed soda cans and the like for the mountains, then covering the whole thing with aluminum foil, and then some clear plastic wrap.
2) In the first part of the lesson I do a demonstration using gravel, carving a U-shaped valley with snow and ice, demonstrating moraines.
3) Then I get out my Aluminum-clad landscape and sprinkle a few gummi worms, telling the kids that they are rocks and boulders.
4) Next, we have us an ice age! I start piling on the blue jello spoonful after spoonful high in the "mountains", while talking about the process of firnification (how snow turns into glacial ice).
5) They watch the jello getting heavier and heavier in the mountains, until gravity starts pushing it downhill -- and the gummi "boulders" start getting pushed down the valley.
Then I have them write a little story of how their school rock got to its present location.
I remind them that the word erratic means "out-of-place", and the rock obviously does not "belong" there, in other word, did not start out there. So while the kids are all quietly writing their stories, I serve up dessert: a bowl-ful of glacier-jello with a few erratics embedded in them...