One of my favourite bits about being a dad is, every now and then, just casually blowing my little boy’s mind – with science. Last weekend, we were out for a stroll when he came out with “I wish I had a rocket so I could go and stand on a cloud”. Sensing an opening, I explained that clouds were made of tiny drops of water that hang in the air, so you wouldn’t ever be able to stand on one. But that, when it’s misty, that’s just a cloud that’s really low down on the ground, so it’s actually very easy to stand inside a cloud. That pleased him, as he acknowledged his chances of owning a rocket any time soon were sadly marginal.