J read the adult version of this book and recommended it, he even tried to read bits to the children but, even though it was funny, they couldn't really engage with it. Then I saw this children's version of it in Smiths.
We've only just started it but we love it! Even I understand it. Bill Bryson is a funny man.
He begins by talking about a school text book he was given as a child which he thought was going to be amazing because of this image (he does admit it was because he imagined cars driving over the edge of the removed wedge and crashing into the burning inner core!)
but when he got the book home he was utterly disappointed because it was dull and didn't answer any of the questions he wanted answering (he now knows that they didn't know the answers then but being a school text book they didn't let on that they didn't know).
His enthusiasm bursts out of the book, I feel that he is just as excited now about the idea that there is a burning ball in the centre of the earth as he was when he was ten. This is perfect for my thirteen year old who is going through an 'I'm not interested in anything except sleep' phase at the moment.
The book is Bill Bryson's A Really Short History of Nearly Everything and we thoroughly recommend it to other science phobics (like myself rather than my children!)