Summer is coming up and finding fun things to do with your kids at a reasonable price can seem daunting.  Why not put together a living system that is not only fun and cheap, but teaches your children about science all at the same time.  This project teaches kids about many concepts from the carbon and oxygen cycles to caring for living creatures.  I have made several eco-columns in the past and found these materials and steps in making one to be the most effective.

Materials needed:  two empty 2-liter soda bottles, 2 cups of aquarium gravel, water, de-chlorination drops, elodea (water plant), one minnow, one large square of gauze, one rubber band, duct tape, potting soil, grass seed, turnip seed, one small cricket, and one earthworm.

Step one:    Parents will cut the top off of a two liter bottle.  You can make the cut about four inches from the top of the bottle.  This will be called bottle 1.  Be careful handling the edges where you make the cut, they can be sharp. 

Step two:   Parents will cut the bottom off of a different two liter bottle.  You can make the cut about four inches from the bottom.   This will be called bottle 2.  Be careful handling the edges where you make the cut, they can be sharp. 

Step three:  Parents will clean the bottles with soap and hot water.  Make sure the rinse all of the soap out with hot water and dry the bottles.

Step four:  Parents will fold duct tape around the edges of the bottles for safety.                    

Step five:  Place two cups of clean aquarium gravel on the bottom of bottle one.

Step six:  Put two to three sprigs of elodea, a water plant, into the aquarium gravel. 

Step seven:  Fill bottle one about three fourths full of water. 

Step eight:  Add two to three drops of de-chlorination drops to the water in bottle one.

Step nine:  Allow the water in bottle one to sit and become room temperature.  Allow the minnow to remain in the same room as bottle one in order for both to become the same room temperature.  Put the minnow in bottle one.  Bottle one is complete!

Step 10:  Fold the large square of gauze so that it covers the small opening (where the lid screws on) of bottle two.

Step 11:  Attach the gauze to the opening with the rubber band.

Step 12:  Put three to four cups of potting soil into bottle two from the large opening.

Step 13:  Sprinkle three pinches of grass seed and turnip seed into bottle two.

Step 14: Moisten the soil with water.

Step 15:  Put bottle two pointed downward on top of bottle one.  Place near the sun.

Step 16:  Wait two to four days until the grass seed and turnips begin to grow.  Continue to moisten the soil as needed. 

Step 17:  Add the earthworm and cricket. 

Step 18:  Cover bottle two with the base that was cut off.  Use clear packing tape or duct tape to secure the base and ensure the cricket cannot escape.

Now, your eco-column is complete.  In the pictures, I used masking tape instead of duct tape.   If you don’t have the exact materials, you can supplement of course.  Over the course of two to three weeks, you can discuss and observe the many ecosystem concepts that the bottle provides discussions about.   Some of these concepts include:

1.   Utilize the two liter bottles to discuss how the materials have been recycled and the importance of repurposing our waste.

2.  The enclosed system really shows kids that oxygen is made by plants and that carbon dioxide is made by consumers. 

3.  The enclosed system also shows the water cycle at work.  The gauze allows water from the bottom bottle to evaporate and reach the top bottle.  Further, you can spot condensation on the inside of both bottles.  There is no need to water anything after the eco-column is put together. 

4.  The enclosed system is a great way to teach the difference between living things and non living things.  If the kids are older you can introduce them to the terms abiotic and biotic. 

5.  The enclosed system also shows the food and energy relationships between the living things in the bottle.  The crickets and fish eat the plant material, therefore are herbivores.  

At the end of two to three weeks, you will want to disassemble the eco-column.  You will want to do this outside because it can be very smelly.  The fish can either be kept in an at home fish tank or released into a pond or lake.  My kids loved taking the minnow from our last eco-column to a pond and letting it go.   Have fun making your very own eco-column and watching your kids learn!


Eco Column

Up close look at the aquarium

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