Bubblus.com is a free online brainstorming tool which doesn’t require downloading of any software. Students can create a concept map without having to sign up. However, if students want to save their work they need to create a free account.
Please note, this site won’t work effectively on a smartboard because the mouse needs to ‘hover’ over the top of a bubble in order to change colour, text and link another bubble. This ‘hover’ function doesn’t work on most smartboards.