Which foods produce the most gases, vegetables or fruits?

	Project title: Which foods produce the most gases, vegetables or fruits?
Difficulty level:	Middle school
Main link:	None

Hypothesis:

I believe that fruits will produce the most gases

Materials:

1. Two 2 liter bottles
2. 2 cups veggies (cucumbers, carrots, cabbage, broccoli, tomatoes, lettuce)
3. 2 cups fruits (orange, banana, apple, pear, grapes)
3. 2 tablespoons dirt
4. 2 balloons

The Procedure:

1. Cut up the vegetables and place in one of the 2 liter bottles
2. Cut up the fruits and place in the other 2 liter bottle.
3. Sprinkle 2 tablespoons of dirt in each bottle.
4. Place the balloons on the mouth of each bottle.

Results:

So far after a week not much gas has been produced in either bottle.
Not exactly sure what needs to be done? Any suggestions, project is due by Mar. 23