Viscosity is a property of magma (and lava), describing its resistance to flow.

Krakatoa is a volcanic island and the name of a famous volcanic eruption in 1883. It's not a property of magma.

Here's how viscosity relates to Krakatoa:

* Krakatoa's eruption was explosive. This was partly due to the high viscosity of the magma involved. Highly viscous magma traps gases, leading to pressure build-up and explosive eruptions.

* The type of magma Krakatoa erupted was rhyolitic. Rhyolitic magma is rich in silica and has a high viscosity. This explains the explosive nature of the eruption.

In summary:

* You can't contrast the viscosity of magma *with* Krakatoa.

* Krakatoa's eruption was explosive due to the high viscosity of the rhyolitic magma it erupted.

If you'd like to know more about Krakatoa or viscosity, please ask!