Have you used BUBBL.US?
It is a simple Web 2.0 tool tobrainstorming and mind map.
Year 4 students are using this to gather their thoughts about their current unit of inquiry about water pollution.
These are a few examples that the students have created.
Another great aspect of using bubbl.us is you don’t need to register. This wiki gives you instructions about how-to use bubbl.us.
Try it today.