Assembling a fish tank is a simple project and requires little experience. Purchase the necessary items at any pet store that sells fish. In addition to a fish tank with a filter, you will need a sand or gravel substrate, living plants, large rocks to create a hide and some aquatic life. Provide variety in the plants and animals you select. An alternative plan would be to visit a local pond or lake and gather necessary components. Ask permission before removing anything from its natural environment.
The items required to build a terrarium can be found in most back yards. Place approximately 2 inches to 4 inches of dirt in the bottom of a fish tank. Dig up some plants (parents usually have no objection to removing weeds from the yard) and plant them in the dirt. Collect small living creatures to live in your created environment. Frogs, toads, salamanders and bugs are usually easy to find and care for. Be sure to research the needs of the living creatures you place in your ecosystem. A daily misting of water will often provide the moisture necessary to keep your ecosystem thriving.
If building an ecosystem is not an option you can simply observe and record your findings directly from nature. Choose an area in your backyard and observe the same area everyday. Record your findings. Document plant growth, insect activity and soil conditions.
A field guide for your area is an invaluable tool when identifying plants and animals. It also contains warnings about potentially poisonous species. An inexpensive magnifying glass allows you to see even small changes in the ecosystem. Record your findings in a spiral bound notebook to keep your notes together.