When it comes to easy projects, making your own miniature biodome is one of the best.
Clear 1 Litre Plastic Container
Large Resealable Storage Bags
To start creating your biodome pour pebbles in the bottom of your plastic container. A one litre ice cream tub should be fine for this experiment. Make sure your layer of pebbles is about a half an inch deep.
Next, pour some soil over top of the pebbles. Make sure you have one inch of soil on
top of the pebbles.
Before you plant your seeds you will need to create a trench about one fingertip deep. The trench should span horizontally across your container. Once you have “dug” the trench
sprinkle a pinch of seeds in it. Then, cover the seeds up with soil.
Next, water the seeds until you start to see water collecting down in the pebbles. Finally, place the whole plastic container in a resealable bag and seal the bag up.
The interesting and easy part of this experiment now comes into play. Your biodome is self-sustaining. You do not need to open the bag at all. The water that you used to water the seeds will recycle itself. When the roots of the plants absorb the water the water will travel back up the stem. Then, it will evaporate when it gets to the leaves. That will cause condensation which will fall back down on your plants like rain.
Adapted from: www.easy-kids-science-experiments.com