Kids' Summer Crafts: Build an Ecosystem

Welcome to summer! My kids have been home since last Friday and we're making lists of fun projects to keep the vacation fun. Each Wednesday this summer I'll be publishing kid projects and today I'm starting with something David's class did months ago.

They built a perfectly contained ecosystem that functions on its own (as an ecosystem is supposed to do) without any outside work or maintenance. They put it together and sat back to watch it grow and mature and I'll tell you, it's really quite fun to see.

There is pond life in the bottom and land life in the top and the two exchange water and oxygen so that you can watch bugs crawling on the second floor and fish swimming in the basement.

I'm not sure how long you can keep it this way but it's been months since they made it and it's still going strong. What a great educational activity and a step up from just going out and catching frogs (also fun). You'll never have to change water or clean a tank or feed an animal--I promise.

Here's what you'll need:
3 empty and clear 2-liter bottles
clear packing tape
aquarium gravel (or fine, rinsed pea gravel)
water
de-chlorinator (optional)
rubber band
4-inch square piece of netting
soil
mustard, rye or alfalfa seeds
fish, snails or other aquatic life
elodea or other aquarium plants
duck weed
crickets, pill bugs or earthworms
a couple dead leaves or small sticks

Step 1:
Cut the top off of the first clear bottle (make sure the labels are removed, you'll need the bottles clear so the sunlight can get through).

Don't cut it too short, just chop off the spout so you have enough of a bowl left over to fill with lots of water. This will be your "bottom floor."

Step 2:
Cut the top and the bottom off of the second clear bottle, making a clear coupler that will eventually link the two other sections together.

Step 3:
Cut the bottom off of the third clear bottle but save it, you'll reattach the bottom with tape after you fill it with good stuff and it will be your "top floor."

Step 4:
In the bottom floor (the one you cut up in Step 1) put an inch of aquarium gravel and fill it nearly full with water. Make sure it's treated with de-chlorinator to take out the chlorine or, if you don't have any on hand, you can set out the water in a shallow pan for 24 hours and the chlorine will evaporate.

Step 5:
Choose your guests! In David's case the class used two little guppies or other tiny pond fish along with two little snails. They also put a couple elodea plants (you can find them in any pet store that sells aquarium supplies) and the snails and guppies live quite happily by eating the plants and algae that accumulates in the bottle, keeping the system in balance. The class also put a bit of duck weed that floats on the top of the water, its pretty little roots dangling down. The plants help keep oxygen in the water and filter the water.

Step 6:
Now fill your top floor. Place the piece of netting over the neck of the bottle and secure it with the rubber band. With the bottle upside-down and the bottom off fill with about an inch of gravel then with a couple inches of soil and plant your choice of seeds (alfalfa, rye or mustard work well and are easily found in health food stores).

Step 7:
Choose your top floor guests. You can use pill bugs or an earthworm or crickets. Lots of possibilities. Let them loose among the grass seeds and throw in a few dead leaves and a stick or two for decomposition.

Step 8:
Replace the bottom to your top floor bottle and secure it with packing tape. You might want to have the top edge fit slightly down inside of the bottom edge (and that's when the bottle is upside down and the soil is in the spout) because as moisture collects in the top part it will trickle down the walls and if the seal isn't tight you'll get water on your counter. Fix this problem by putting the edges down inside of the edge they're to join up with. (Make sense?)

Step 9:
Slip the taped up bottle down into the coupler, secure it with packing tape and then slip the bottom edge of the coupler down into the top edge of the water-filled bottom floor. Secure it with packing tape.

Step 10:
Place in a well-lit spot where sunlight can get through the clear plastic to do its work. Sunlight will allow photosynthesis which will keep the cycle in motion. Keep an eye on your guests, our snails had a population explosion and we had baby snails everywhere. It's really quite exciting.

Sponsored by Polkadot Peacock for children's bedding.