Magma’s Viscosity (determines volcano type)

What is viscosity? • Science Definition – a fluid’s

ability to resist flowing • Easy Definition – a fluid’s

thickness/stickiness

Viscosity Demonstration• OBJECTIVE: determine which liquids

are more or less viscous.• Use the numbers 1 (least viscous)

through 4 (most viscous) to rank the liquids.

Vegetable oil

Maple Syrup

Honey

Ketchup

What does it have to do with volcanoes?

The viscosity of magma/lava

determines what type of volcano it is.

Remember the following…

low viscosity means “runny” lava that flows easily Low amount of silica forms a gentle slope

volcano

high viscosity means “sticky” lava that flows slowly High amount of silica forms a steep-sided

volcano

Lava Type Silica Content

Viscosity Appx. Flow Rate

Basaltic Low Low30-60 km/hr19 - 37 mph

Andesitic In between In between 10 km/hr

6 mph

Rhyolitic High High1 km/hr0.6 mph

What lava type could each of the 4 liquids from the demonstration represent?

oil = Honey =

Syrup = Ketchup =

Time to build our own

volcanoes!!!

http://dsc.discovery.com/convergence/pompeii/interactive/interactive.html