Driest place on earth and geology from a power pole

It was very hot today (33degC) and on the way to the shops S (7.5yrs) declared he was so hot his brain felt like it was frying and that was it this hot in the desert atm? To which I replied that it was probably hotter. He then wanted to know where was the driest place on Earth? I
suggested it might be Antarctica as it doesn't 'rain' there that being the definition of a desert and technically Antarctica is a cold dessert, but that maybe it was also somewhere like Death Valley in USA. We decided to check this out on the internet when we got home. We now know that it is the Attacama Dessert on the Western coast of South America.

One of the power poles up the road was replaced today and the old pole was lying on the verge when we went shopping... on its base was a lovely record of the soil types from surface down to about 2.5m. This was mostly white sand. On the way home I asked S where we usually see white sand, to which he replied the beach. I then told him how this area was once part of a beach, in fact all of the Perth coastal plain has been beach at some point. Then we got talking about when this happened, before or after the dinosaurs and why (changes n sea levels).

I made the comment that there are places up North in WA that have rocks not just millions of years old but billions of years old on the surface and we discussed how this could be (Australia's crustal plate not having been recycled by going under another plate for that long and building up and wearing down of rock/soil) and how old the earth was in relation to
the solar system and the big bang.

Just a sample of the learning that takes place whilst we are out doing the shopping....

K