Dirtmeister's Science Lab Home

Here's what you'll need:
two clean, clear 2-liter plastic soda bottles
clear plastic wrap
two "loose" rubber bands
a small watering can
a small bottle of lemon juice
some grass seed or bird seed
a small pail of good old garden dirt (not potting soil)
a ruler
marking pen and two labels
 Here's what to do:
 1. Take off any labels on the bottles. Use the scissors to cut the top off each bottle about 20 cm. (8 in) from the bottom.
 2. Fill each bottle about halfway with soil; scatter the seeds on the top.
 3. Use the watering can to wrinkle about 250 ml (1 cup) of water into each bottle.
 4. Place a piece of plastic wrap over the top of each bottle; use the rubber band to keep the plastic down around the sides of the bottle.
 5. Place the two bottles on a sunny, warm windowsill or near a bright lamp.
 6. Label one bottle "control" and the other "test."
 It will take three to five days for your ecosystems to become established, so be patient! At least once a day, you should carefully observe each bottle and record any changes that you see, including the presence of any little life-forms. Once the grass and other organisms start to materialize, try altering one of the ecosystems.
 1. Uncover the plastic wrap from your two ecosystems.
 2. Sprinkle a half cup of pure water over the "control" ecosystem every other day. Over the "test" ecosystem, sprinkle a half cup of pure water mixed with 2 tablespoons of concentrated lemon juice every other day.
 3. Leave the plastic wrap off the top of the bottles.
 4. Carefully observe each ecosystem daily for at least one week and list all the changes and organisms you see.

1. What type of an effect did "acid rain" (or lemon juice) have on your ecosystem?

2. Before you try this Science Lab, predict with your classmates how you think your mini-ecosystems will react when you start to water one with a weak solution of lemon juice (acid) and water? Will everything die? Will only one thing be affected? Maybe nothing will happen at all.

When you've finished the Science Lab, share your results with the rest of your class. Make sure you explain how you got these results. Be sure to answer the challenge questions!
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