You will need
A clean, transparent 2L PET bottle
Scissors
Stickytape
Soil
Pebbles
Charcoal fragments
Small plants
Instructions
1. Cut the top off the PET bottle using scissors or a sharp knife.
2. Add a layer (about 1 cm deep) of charcoal, followed by a layer of pebbles (about 2 cm deep) and a layer of soil (about 5 cm deep).
3. Stick some holes in the soil and add some small plants. You could also add a layer of moss. Tape the top of the bottle back on.
4. Place your mini biosphere in direct sunlight and water occasionally but not too often - the water in the container should evaporate and condense on the sides of the container, creating its own water cycle.
