When all you have to do is explain to a child (or indeed a layman adult) you can use things like analogies that aren't perfectly accurate, and you only need go a little way beyond the person's existing knowledge - it's a waste of time to deliver more information than they can absorb in the time you've got to explain.

If you're a high energy experimental physicist you can say you work on a particle accelerator. That's a machine that makes particles hit into each other really fast, a bit like a super-high-speed game of conkers! When the particles hit together and break apart for a really short time you can see the parts that make them up, and you can learn things about them!

You've now explained what you're doing to an 8 year old! But if you ask the 8 year old whether they think it's a good idea to use Fox-Wolfram moments to partition phase space and suppress the continuum background, like B-factories do, or whether you'll have difficulty determining the centre-of-mass frame due to missing energy? Probably the 8 year old won't have an informed opinion either way.