Activity: Terrarium

Nikita and the terrarium

On SCOPE's Rainforest episode, you saw Nikita build a mini rainforest. Here's how she did it:

Watch the clip.

What you need

• 1 plastic soft drink bottle with the label removed and the top third cut off
• Some gravel or sand
• Some potting soil
• Small plants
• A few worms or insects

What to do

1. First up, place a layer of gravel or sand inside the bottle.
2. Next, put the soil on top of this layer, until your bottle is about one third full.
3. Now it's planting time. Just poke a hole in the soil with your finger and add your plants (or you could plant seeds instead).
4. Give your terrarium a good water.
5. Add any creepy crawlies like worms or slaters to your mini-ecosystem.
6. And lastly, seal up your terrarium by sticking the top back on top with sticky tape.

What's happening?

Rainforests ecosystems are rich, complex and generally pretty big. This can make it tricky to learn how the soil, water, air, plants and animals of a rainforest interact with each other.

But, we can take a good look at these things in an ecosystem a little bit smaller than a rainforest.

This creation is called a terrarium, which is basically a small enclosed ecosystem. But your new mini-ecosystem can do more than just look good. If you watch what's going on in there over time, you can observe some of the important processes that occur in life-size ecosystems.

Like the water cycle. The water in your terrarium is recycled as it evaporates from the soil and plant leaves in warm temperatures before condensing on the walls in cooler temperatures, and 'raining' back down to the soil. And because there's not much chance for water to escape from this cycle in your terrarium, you'll rarely need to add more. Just water it again when you notice there's no longer any condensation forming on the walls.

Aside from the occasional watering, your terrarium will require very little maintenance. The soil, water, air, plants and animals inside the bottle function together as a system, which is almost self-sustaining. So you can pretty much just sit back and watch the components of your bottled ecosystem do what they do best.