Pond snails can live in a mini-biosphere.
The word biosphere means "life ball" and refers to the part of our Earth that contains all living things, and things that were previously alive but have not decomposed. Earth scientists categorize our planet into four interdependent parts: the biosphere, the atmosphere (containing all of Earth's air), hydrosphere (containing all forms of Earth's water) and the lithosphere (containing the Earth's core and the layers of solid and liquid rock that make up the Earth). These parts all affect one another or interact. Students can make their own biospheres and observe a living system that goes through cycles and changes over time.
Mini-biosphere
A jar of pond water containing algae, water plants, tiny creatures, bacteria and fungi make up a simple biosphere. For this activity, each student will need a clean pint or quart glass jar with a screw-on lid, hand lens or microscope, nail, small candle, notebook, pencil, crayons or colored pencils and supervised access to a pond. An adult or older student will need a hammer and a match or lighter.
Make a hole in the lid using the nail and hammer. Light the candle and drip wax into the hole in the lid. This acts as a pressure relief valve if too much gas builds up inside the jar. An adult can help younger students with the above steps. Under adult supervision, each student should collect a ½-inch to 1 ½-inch base of pond mud containing small insects and animals, such as snails, in the jar. Add algae and small water plants. Add water from the pond to fill the jar three-quarters full. Observe the various elements of the mini-biosphere with the hand lens or microscope. Record, illustrate and date observations in the notebook. Younger students can draw a picture of the mini-biosphere in their notebook. Allow the mini-biosphere to sit untouched for a week in a brightly lit room but out of direct sunlight. Each week, observe the mini-biosphere and record any changes. A small amount of water may be taken out each week to examine with the hand lens or microscope.
Simulated Environmental Changes
Older students can perform experiments that simulate the impact of various environmental changes on a biosphere. Allow the students to compile a list of variables they would like to test on the biosphere. Some ideas might include comparing no light, 12 hours of light and 24 hours of light; cold and warm temperatures; small amounts of salt or fertilizer added to simulate salt or fertilizer runoff, or blocking certain parts of the light spectrum by covering the jar with various colors of cellophane. Students should make enough mini-biospheres to conduct their experiments plus one for a control. Record the results of the experiments and observations in a notebook.
"Lunar" Biosphere
Older students can design a self-sustaining, balanced biosphere that might be used on the moon where the conditions for life are not favorable. Two weeks before starting this activity, sprout mung bean, radish, tomato and peanut seeds in trays containing soilless seed-starting mixture. Coordinate the collection of various soils such as cinder, clay, fertilizer, gravel, loam, potting soil, sand, silt and vermiculite. For this activity, each student needs a 2-liter plastic soda bottle with a black base, pan of hot water, craft knife, duct tape, clear plastic tape, notebook, pencil, colored pencils or crayons.
Remove the soda bottle label. Soak the bottle with the black base down in the hot water. When the glue softens, pull the base off the bottle. Cut off the spout end of the bottle. Plug holes in the black base with strips of duct tape on the inside of the base. Design possible sets of variables such as type of soil or soil mixture, amount of water added, type of lighting (lamp, sunlight grow light, etc.), type of seedlings and types of small animals and insects. Assign each student a different set of variables. Collect the small animals and insects such as beetles, ants, spiders, snails, slugs and sow bugs. Add the soil, plants and water to the black base. Add the small animals and insects. Turn the clear part of the soda bottle upside down and insert into the black base. Tape the two pieces together where they join and do not reopen the container. Label the "lunar" biosphere with the date, the student's name and the variables contained in the biosphere. Record observations and illustrations in the notebook. Observe weekly for several months. Determine which variables produced the best results. Consider the conditions of the moon such as the lack of atmosphere, water and topsoil, the length of lunar days and nights and how you might overcome these challenges.
Biosphere Research
Advanced students can research the Biosphere 2 project in Arizona and present a report.
Tags: black base, each student, animals insects, hand lens, hand lens microscope, lens microscope
