Bottle Ecosystem, This is the most awesome class idea to teach ecosystems! Its self contained and you can observe the activity for the rest of the year. No mess no fuss and all of this cost about 17 dollars.
Best science experiment ever! Make a fatastic eruption with hydrogen peroxide, yeast, soap, and food coloring! Perfect for science shows for all ages: preschool, kindergarten, elementary, middle, and high school! Even adults enjoy this one!