I’ve been making bottle biomes on and off for about 10 years. They’re a fantastic way to show the cycling of air and water in a sealed biome. Students can easily relate this to Earth. You may see examples online where they add small insects to the biome. I don’t as (a) I don’t think it’s fair and (b) it complicates the biome.

The instructions are fairly simple. The only thing you need to make sure of is that you don’t add tap water. Rainwater or pond water is perfect, as they contain all the micro organisms the biome needs.

Students should observe their biome over a number of days. They’ll see condensation on the inside of the jar as the heat evaporates the water in the soil and it cools and condenses inside the jar where the cycle begins again.

You can download this activity for free. The resource contains teacher instructions, student instructions and an answer sheet.