Is the Earths core really what you think?
The earths core is a molten mass of boiling rock trying to erupt through volcanoes, or is it?
Scientific research has shown that the earths core is actually consists of a collection of minerals and elements presented as a solid ball made of mostly a nickel and iron alloy.
The actual core diameter is roughly 70% of our moons radius, so around 1,211 kilometres. The surface of the earths core has a temperature close to that of our sun, around 5,700 K or 5,430 °C.
This was the discovery of a Danish seismologist by the name of Inge Lehmann in 1936. This inner core is thought to be slowly increasing in size as its surrounding mass cools and solidifies. This central part of our planet rotates inside the solid surface we walk upon at a slightly faster rate than the earths known rotation. Only around 1degree each year of extra rotation.
So, the lava we see erupting from our volcanoes does not actually come friom the core of the planet but from the viscous molten magma below the earths crust.
The viscosity of lava is around 100 times that of water but can vary by a reasonable amount depending on composition, mostly of silicate minerals such as feldspars and quartz.