How do we know the outer layer of the core is molten

But it may surprise you to learn that, in between the solid inner core and the solid mantle, lies a liquid layer more than 2,000 kilometers thick: the Earth's outer core... The way we know that the outer core is liquid is quite brilliant: from the seismic waves produced from earthquakes.

Aproximately 5 pieces can be cut from it.

The  knowledge gap  as been recast more recently as a “digital divide”  gap. with the internet and social media many things can be done faster and better. so much faster and better that those that do not have access to them are literally left out of the game.