This is a unit that incorporates a lot of hands-on activities which tries to provide students with opportunities to create models, to practice inquiry skills, to work with fellow students in teams, and to reinforce concepts discussed in class all by using the theme of BIOSPHERES. The target audience is mainly biology, although it could easily be integrated into a life science or environmental science class.
I have done this unit for 7 years, from second graders in our Future Flight Hawaii space program, to gifted and talented biology students in high school. I've adapted it to a space theme and an environmental theme. I will be presenting this Biosphere unit using a space theme from our Future Flight Hawaii program that I wrote up.
Peperation Time: A couple of days
Class Time Needed:
- 1 class day to make mobiles, to discuss major concepts, and to start planning their biospheres.
- 1 class day to set up and completely seal their biosphere(s) and to start taking data on it.
- 5 weeks- to take consistent, daily observations every class day. This can be done at the beginning of each class day, at the end, or on their own time (this will be at the teacher's discretion).
Scenario (for students):
You are an alien form on a distant planet. Your home world has received distant radio transmissions from a particular solar system and you have been sent as the head biologists on this mission to find the source of these transmissions and to see if life exists there. Your expedition team has traveled through the outer parts of this solar system and discovered no signs of life. But now you are approaching the unique and awesome Blue Planet.
Your Mission (for students):
Unlike your home planet in your far away galaxy, you have found the blue planet to have liquid H20, fascinating types of environments & Life!! You need to take a part of this unique biosphere you have never seen before, home to your fellow aliens so that they might have a "taste" of all you've experienced and seen. You want to collect some of these living things in their natural environment but you want to be sure they'll survive the long journey home and also be able to reproduce.
The biosphere, or "Living Ball" is all the living and nonliving parts of the Earth that sustain life. Organisms can be found in almost every place on Earth. At the start of this unit, I introduce the concept of a biosphere. I use a mobile with a leaf, the sun, animals, a zip lock bag sealed with air inside of it, and a cloud hanging and balancing on it, to emphasize the importance of balance in a biosphere. If there is time, I have the students create their own mobiles (for the lower grades, mobiles are kept simple; for the high school students I have them make multi-tiered mobiles showing interrelationships in the biosphere). I then relate this concept to space travel and share the scenario and mission statement with them above. (The students also love to come up with their own alien design, name, etc.) Students begin to realize their alien space craft is a mini-biosphere and that all systems must be balanced and self-sustaining in order for them to survive.
After this, I have my aliens start designing their biospheres, researching the living things they are finding, and deciding what to seal up in their 1 gallon mayo jars. As alien exobiologists, they need to determine what type of ecosystem will be the most successful on their long 5 week journey home, and what type and number of organisms will be able to survive in such limited living space and resources. In class, we seal the jars and my alien exobiologists observe them for a minimum of 5 weeks. They regularly take observations, and create colorful sketches which they eventually put together into a full 20-40 page report. (Happily, I've found many of my students running into my class before the day starts or during breaks-even on days when I don't have them - just to get a glimpse of their biosphere and to see if it is still balanced and surviving.) As the weeks progress, students also begin to catch on to the importance of biogeochemical cycles in a biosphere.
The next phase of this unit again relates the idea of space travel to the importance of a self-sustaining biosphere. "How can we, as humans, survive in outer space?" "How can we grow plants in space- in a space station, on the moon, or on Mars?" "Is there fertile soil on the moon or Mars?" "Is it economically feasible for us to bring soil into space?" After we discuss these types of lead questions, we then go on to several extension activities.
The scenario now changes. They are humans again, but this time colonists on the moon. Their mission is to design and build a lunar biosphere, using materials they think they can find on the lunar surface/sub-surface. Students will add terrestrial animals and plants and then seal the system. For students who want to do more, they can design and build a martian biosphere.
I then discuss once more with my students, the economic unfeasibility of growing plants on the moon or mars using soil from Earth. (It's too expensive!) "What can we do to grow plants?" Some believe it's impossible to grow plants without soil. With that, we do a hydroponic unit using a nutrient solution along with polycrystals and rockwool, creating hydroponic biospheres. (One teaspoon of polycrystals can absorb over 200 times its weight in water and will expand to about 3/4 cup when hydrated. Rockwool is spun basalt and serves as an excellent medium to grow plants in. It is also very lightweight.) We then do a three-way comparison of growing seeds--in soil, polycrystals, and rockwool--and we determine the most efficient and successful medium.
FOR THE FIRST SCENARIO AND MISSION:
Have the students bring in their own 1 gallon container/jars. You may want to bring in a few, just in case. Also, assuming the students can afford it, have them decide and bring in all their own biotic components themselves. (I usually have them work in teams.) You would want to have measuring balances, measuring cups, and rulers available for students. Fluorescent lamps do well. Have one or two fish nets ready for students who may need help putting their fishes in, and also have buckets, sponges and soap ready for clean up at the end of the period. Finally, have rolls of tape ready to cover their lids after they seal them, and have permanent markers to write their names, period, date, and time the biosphere was sealed.
Procedure/Description of Unit:
- Introduce the concept of biosphere, using the mobile.
- Have students design and build their own mobile showing their own concept of a
biosphere and the complex interrelationships between abiotic and biotic factors.
- Introduce the scenario and mission.
- Break students into alien teams of 2, (for middle/elem., you may want to make larger
- Have them design their biosphere, research their abiotic and biotic parts, and decide
what types and numbers of living/nonliving things they are going to seal into their jar.
- On the BIG MISSION DAY, have them bring in all their things and actually create and
seal their biospheres. Be sure students write their names, date, period, and time
in permanent ink and also double check that all biospheres are completely sealed.
- For the next 5 weeks, have students regularly take observations, either at the beginning
or end of each class period.
Have them keep accurate daily records of their observations and sketches.
- During the 5 weeks, you may want to go on and do the extension activities.
- After the 5 weeks are over, have students go over the successes and failures of their
ecosystems and analyze the rest of their data.
- Have the students turn in a final report 1 week later.
FOR EXTENSION ACTIVITIES:
- Clear plastic bins (like the ones to put hamburgers in)
- Fine dirt
- Basalt rocks, etc.
- Sealing tape
- Biotic materials like plant seedlings and insects
Procedure/description of activity:
- Have students break into teams and brainstorm what they feel a lunar biosphere
should look like and how it should be built.
- They should then try to create one using materials they think they would find on the
moon (cinder rocks, very fine dust, etc.) -- have them put the abiotic materials into
the clear plastic bins.
- Then they should add the biotic parts, seal it and watch it hopefully grow -- they
could also compare the lunar biosphere with their terrestrial one.
- Peanut and mung seedlings
- Plastic bins
- Nutrient solution
- Viewing tank
(*see references to learn where to order the rockwool, nutrient solution, and viewing tank)
- Potting soil
- 2 clear plastic bins
Procedure/description of activity:
- Assemble viewing tank, following the directions given with the unassembled kit*.
- Open up 6 packets of polycrystals - equiv. to about 6 tablespoons.
- make 1 quart of nutrient solution, using 1/4 tsp. of nutrients from bottle "a" and 1/4
tsp. of nutrients from bottle "b"*.
- Cut the rockwool into 1/2 inch cubes-- (*rockwool ca be ordered in small sheeet sizes-
see references below)
- Germinate seeds (I've used peanut seeds and mung beans.)
- Get potting soil.
- Pour 1 pint of the nutrient solution in a 14oz. plastic container.
- Add the 6 packets of polycrystals to the pint of nutrient solution in the container.
- Wait 1-2 hours for the crystals to hydrate completely.
- If necessary, add more nutrient solution until the crystals are almost saturated.
- Add the hydrated crystals directly into the viewing tank.
- Add 3 peanut and 3 mung seedlings to the tank. Be sure roots are properly immersed
into the crystals.
- Next, get 6 1/2 inch cubes of rockwool. Pour the nutrient solution over the cubes until
they are saturated.
- Use a pencil and create a "well" in each cube about 1/4-1/2 inch deep.
- Plant 3 peanut and 3 mung seedlings, one in each cube. Then put 3 cubes each into a
plastic bin and close the lid. (do not seal)
- Finally, put potting soil into 2 small pots and plant the 6 seedlings about 1 inch apart in
the soil. (3 in each pot) Use the same nutrient solution to water them.
- Observe daily and compare your findings.
METHOD OF EVALUATION:
- For the first scenario and mission, the main mode of evaluation will be their report.
The report should include their daily written observations and sketches and also their
analysis of their findings, including a look at the successes and failures of their sealed
mini-biospheres. Team members can also evaluate and assess their teammates progress
and contributions in a peer/team evaluation form during or at the end of their project.
Assessment will also include the success rate of their biosphere and how well planned it
- For the extension activities:
- Lunar biosphere:
mainly looking at the creativity and accuracy of their design. Also will be assessing
the survival rate of their lunar biosphere and looking at how well they understood
what a biosphere was and transferring it to another location (the moon).
mainly will be assessing them through their report and verbal discussion of their
findings. Will be evaluating them on the accuracy and analysis of their findings.
*The polycrystals and viewing tank can be bought from the following company:
- Captivation, Inc.
- 9 Cannongate Drive
- Nashua, NH 03063
- (603) 889-1156
*The rockwool and nutrient solution can be bought from the following company:
- Great Bulbs of Fire
- RR2 Box 815
- New Freedom, PA 17349
- (717) 235-3882
- (717) 235-7144 (fax)