Brain training

'Did you know the sea isn't really blue?' asks Lily.

I am caught up in my own world, wavering over the bin liner bound for the dump and the one bound for the charity shop, with a telescopic umbrella with two bent spokes. 'What?'

'Did you know the sea isn't really blue?'

'Yes.' I think, on balance, I did know this.

'Did you know the sky isn't really blue either?'

'Yes.'  I drop the brolly in the bin liner that's bound for the dump. Love the new Louisa-injected ruthless spirit.

'Did you know that clouds were just water vapour?'

'Yes. Totally.'

'Did you know that your hair is made up of living cells?'

'Hang on, I thought once the hairs come out of the head, they're dead.'

Lily is rooting around in the fridge. 'Did you know Saturn has more than two rings? You can only see them through the Hubble telescope thingamajiggy.'

'Hmmm.' I turn to look at her. 'Did you clean your teeth?'