Scaling several objects at the same time, making them move apart, without actually scaling the objects,

I know it's possible, I have done it before, but I can't remember how to do it.
Suppose you have 5 circles arranged in a circle. I could select them, use the function I can't remember, so that they radially 'drift' apart, while maintaining their original scale.
If anyone knows how to do this?

@Gremriel You need to press the spacebar after you begin to scale the selected objects.

Thank you. I knew it was something that simple, but for the life of me, I couldn't remember