My baby just banged her head for about the third time this week 
She is just coming up to 6 months so rolling, sitting and trying to crawl flail along the ground. If she sees something she wants she just launches herself at it but this has led to a couple of bumped heads. The same with her sitting- she sits really steadily for ages and then suddenly reaches for something, unbalances and falls backwards. I sit on the floor next to her/with her between my legs but it takes 1 second of inattention for this to happen!
She is playing on a playmat in her carpeted bedroom- I daren't let her on the ground on any of the wood floors in the kitchen and living room!
How can I prevent her bumping herself whilst letting her explore physically?