To be able to express a complex intellectual model and describe things accurately requires *language*. (Also having a large vocabulary of interesting words is a real intellectual-class winner in the school playground.)
And finally from me, find compelling analogues or fun experiments. If the Earth was the size of a full stop, the Sun would be about the size of a ten pence piece 2 metres away. Now as our good friend Mister Oxbarrow says "On the scale of fishy that's a whole lot of pilchards." When you think about it the idea of a speck floating in some infinity around a blob all that distance away is bizarre. If you roll a marble past a football it keeps going straight and doesn't get bent towards the football by gravity. The whole thing is clearly bonkers.