I finally got off of my rump this weekend and started making my geography materials. I thought I would begin with the land and water forms. This is a material I do recommend making yourself. The least expensive set I have found to date run $84 and I know I can do it for less than $10.
I thought I would follow Gettman's instructions and make them out of Plaster of Paris. I haven't used Plaster of Paris (if ever) since elementary school. I mixed my powder and water and prepared to "make a roughly finished Plaster of Paris formation in the desired shape" as Gettman so calmly stated. In my mind, I pictured the powder and water forming a claylike substance I would form with my fingers and let dry. I realized I was on the wrong track when my batch of Plaster of Paris was the consistency of whole milk. I knew I was even further off track when I read the warning on the container that contact with skin would burn.
So, I went on to Yahoo Groups "Montessori Makers." I knew most people do it with plasticine, but wanted to see what people had to say about Plaster of Paris forms. I read that I would have to make a "mold" out of sand, cover it with plastic wrap, pour in the plaster and let it dry. Next, I would paint and waterproof the product. Then I read that after all of these steps the plaster shapes would have to be glued to the landform and would rot.
It should not be surprise that the above images are not of my finished landforms. It should also not be a surprise that I aborted my landform project until plasticine can be procured. I went ahead and began making my sandpaper globe. Stay tuned for "How NOT to make your own geography materials: Part Two, Sand and Water Globe." Grrr.