Confession, I’m a mad keen gardener. My love of gardening comes from the memories connected with it: planting seeds with my dad, climbing the apple tree and, of course, making mud pies in the patch of ground next to the cubby house. In an early childhood environment where things have become increasingly sanitised and regulated and soft-fall and designer spaces are common, there is less space for the gardens of my youth. So how do we, as educators, help our children make those connections?
What do you need?
Four or five pieces of uncoated 100% cotton the same size (perhaps cheese cloth), trowels
Where to start?
This takes time and patience. The children bury each piece of cotton in a different soil type in your yard. Perhaps one in the sand pit, one in the gravel near a path, one in the garden bed and one in the compost. Remember to mark where you have buried them (I made flags out a stick and pieces of the cloth I had buried). Then you wait and wait and wait. I told you it would take patience! You may be able to observe some differences after one month, but it would be even better to leave the cloth buried for two months. Dig up the pieces and see how they have decomposed.
What’s the STEM?
When you dig up the pieces of cloth, you can check their levels of decomposition. If there is not much left of the cotton, there has been good biological activity, which indicates healthy soil. These organisms in the soil break down plant materials in much the same way. If the cloth you buried is still intact, then there is not much biological activity. It is worthwhile talking to the children about why this can be a good or a bad thing.
Talk to the children about friendly microorganisms: bacteria in the soil helps break down organic matter, such as old leaves, and make the nutrients available to plants.
If you don’t have several different areas in your yard, you can use pots of different soil. You can even sterilise some soil by baking it in an oven at 200˚C for 30 minutes and compare the decomposition in ordinary versus sterilised soil.
Our wonderful Little Scientists House Sweetpeas Kindergarten in Cranebrook chose a slightly different set-up for investigating decomposition. They buried different things such as vegetable scraps, plastic and cotton in the same soil to check how these items break down over time. We enjoyed reading about this project, which was submitted as part of their Little Scientists House application.
Another great investigation is to look at the texture of the different soil samples you have gathered, just like we’ve done in one of our Little Scientists at home videos.
Use your explorations to introduce this STEM vocabulary to the children: Microbiology, microorganisms, dirt, mud, compost, gravel, clay, sand, soil, potting mix, decompose.