Winter Sand Art Earth Layers

Our second project for winter Over, Under, and Through the Woods was earth layers in a jar.
We used bright colored sand instead of more "realistic" earth layer colors because bright colors are so much fun.  I ordered sand from Amazon, but I think it actually came from Oriental Trading, so I'm not sure which is actually cheaper, ordering through Amazon or directly from Oriental Trading.  I ended up buying three cases for 22 people and used all of some colors, but have some left over of others.
I bought rectangle vases from Ikea to put our sand in.  I know they are open and don't have a lid which could result in some messes, but for this project I wanted to do something a little different then your typical tiny bottle of sand sand art.  I also wanted the kids to be able to put houses and trees on top and a small opening wouldn't allow that.
I used this reference for the layers of the earth:  http://scienceblogs.com/startswithabang/files/2011/09/Layers-of-Earth.jpeg
and drew this one without color and with measurements of sand for easy photo copying:

Just in case it's a little hard to read we used 6 tablespoons (T) of sand for the inner core, 6Tfor the outer core, 14T for the lower mantle, 4T for the upper mantle, 3T for the lithosphere, 3T for the crust or mountains and land, and 1-2T for the water.
I ended up making my own house template for the students to draw details on:

It's pretty simple.  Cut on the solid lines and fold on the dashed lines. The thin rectangle on the left and the top right are tabs.  Put glue on the tabs after folding it and stick it to the other side.
For trees we used a large fluffy green pipe cleaner.  I wanted to make my own bottle brush trees like these:  http://justsomethingimade.com/2013/11/handmade-colorful-bottle-brush-trees-at-goat-hill-fair/  but decided I didn't have time and it would be too much work for some of the kids.
We used a chopstick to poke layers down.  I tried to put a straw up against the glass and poured sand around it and then red sand in the straw to make lava coming up, but it didn't work very well.  I couldn't get the straw to stay close enough to the edge of the glass while adding sand.
They turned out so much fun :-)  I loved watching some kids make bridges and boats or other buildings for a little town or village on the top of their jar.