How to use metaphors to explain complex ideas.

Interestingly, we see this phenomenon extremely often in the works of the popularizers of difficult complex scientific theories. A number of works by well-known authors such as Stephen Hawking, Richard Dawkins or Isaac Asimov are simply replete with metaphors in which complex topics from areas as diverse as quantum mechanics, genetics and chemical interactions are explained by comparisons to more mundane topics much more likely to have been experienced by the audience than the erudite musings or laboratory rituals of the acolytes of those arcane arts.

You need only to associate the complex thing with something that is familiar to your audience.

If your children are familiar with cats then describing a tiger is easy by calling it a big cat.

One of the big things you need to do is to expose you children to lots of different peoples, ideas, places, things, and activities. That way they can form more associations and connections in their brains and so develop further.