Suitable for elementary- and middle school-age children, a basic biodome introduces students to the fundamentals of sustainable environments as well as the water cycle. Using a transparent one-to-three-liter plastic container, large resealable storage bags, soil, seeds, water and a ruler, the creation of a biodome is simple. After lining the bottom of the container with a half-inch of pebbles, 1 inch of soil is evenly distributed over the top of the pebbles and seeds planted in the soil. The plants used should ideally be suited to the moisture within the container after it is sealed. Once the seeds have been planted and covered with soil, water is added until it becomes evident among the pebbles at the bottom. After placing the container in a sealed plastic bag, the biodome is exposed to sun to allow for seed germination and growth. Basic biodomes are self-contained experiments that allow children to see the effects of the water and growth cycle. As the plants develop, children observe and record the absorption by plants of water, which then evaporates out of the leaves and creates condensation on the inside of the bag before it is reabsorbed by the plants. However, the moisture is not unlimited, and as water decreases, children will observe the deterioration of the environment.
Altering the amount of water in the biodome allows kids to analyze and experiment with different moisture levels. For this experiment, students will create three separate basic biodomes with different moisture levels. For example, kids should be asked what they think will happen in the first biodome, in which water adequate to the types of plants contained in the biodome will be added, while the second biodome will have more water than needed and the third have much lower water levels than needed. As the biodomes are allowed to develop, children will analyze the differences in the growth of the plants, as well as evidence of the water cycle. Prior to the experiment, should be encouraged to hypothesize on the effects of different moisture levels and, after several weeks of observation, be asked to revisit their predictions by presenting evidence to support or refute the initial claim.
Plant life relies on moisture to perform the process of photosynthesis, in which the plant rejuvenates itself through the recycling of water by way of the water cycle. However, excessive heat decreases moisture and the plants’ ability to properly perform photosynthesis. A biodome experiment concerning the effect of heat on plants helps illustrate the delicacy of natural processes. To perform this experiment, kids first construct a basic biodome and allow plants inside of it to grow under optimal conditions. After the plants have established roots, the biodome should be placed in direct sunlight to increase the temperature within. Leaving the biodome in direct sunlight, children observe and analyze the changes to the plant life. As the exposure continues, children should be instructed to consider any changes in photosynthesis that might be evident to the naked eye, such as decreases in condensation and evaporation.
The addition of animal life to a biodome model can provide a more complete view of the environment’s biological equilibrium. Experimenting with the effects of this new balance within the biodome allows kids to observe the role of animal life in the ecological system. For this experiment, kids will need two biodome models. The first biodome model will be a basic environment with only plant life. The second model should be an exact replica of the first, including the same amount of soil and water as well as the same plant species. However, the second model will contain animal life such as isopod insects or earthworms. As the biodomes develop, children will observe the growth of the two biodomes and keep record of the health of both plants and animals. Kids should be asked to consider the effects of both animal and plants sharing the same limited resources. In addition, they should also pay attention to any deviations in the water cycle within the biodome.