Download volcano is a weak spot in the crust

Section 3.1 (p.82 - 85)
- volcano is a weak spot in the crust
- magma/lava
Volcanoes and Plate Boundaries
- volcanic belts form along the plate
boundaries
- Ring of Fire = volcanoes that rim the
Pacific Ocean
Diverging Boundaries
- Volcanoes form along mid - ocean
ridges at divergent boundaries
Converging Boundaries
- many volcanoes form near converging
boundaries where oceanic plates get
subducted
- rock above the subducted plate melts,
forming magma - it moves to the surface
because it is less dense
- island arc = string of islands/volcanoes
form along the deep ocean trench (convergent
boundary)
Hot Spot Volcanoes
- A volcano forms above a hot spot
when magma erupts through the crust and
reaches the surface
- an area where material deep in the
mantle rises then melts, forming magma
- can gradually form a series of volcanic
mountains
- Hawaii (example)
- Yellowstone National Park (example)
Section 3.2 (p. 87-90)
Physical and Chemical Properties
- elements
- compound
Physical property - can observed without
changing the substance (color, density,
hardness, melting/boiling points, magnetic,
states of matter)
Chemical Properties - any property that
produces a change in the composition matter
(change in a chemical formula - new products)
examples = ability to burn and ability to
combine or react
What is Viscosity?
- viscosity is the resistance of a liquid to
flowing
- viscosity caused by the movement of
particles
- friction between particles as they move more friction, higher viscosity
- greater viscosity, flows slower (honey)
- lower viscosity, flows faster (water)
Viscosity of Magma
- viscosity of magma depends on 2 things
- amount of silica and temperature
Silica Content
- more silica, high viscosity (slow)
(forms rhyolite)
- less silica, lower viscosity (fast)
(forms basalt)
Temperature
- high temp, lower viscosity (fast)
- Pahoehoe
- low temp, high viscosity (slow)
- aa