Objective: To learn about the properties of magma 1/9/13 Bell Ringer Where are volcanoes found? (Look in yesterday’s notes) Heredity C A B Objective: To learn about the properties of magma

Agenda Go over homework Notes on magma Video and Demonstration

Homework pg. 203 What is a volcano? Where are most volcanoes located? A weak spot in the crust where molten material reaches Earth’s surface Where are most volcanoes located? At converging and diverging plate boundaries. There are a lot of volcanoes in the Ring of Fire and some at hot spots. What causes volcanoes to form at a diverging plate boundary? There is a crack in between the crusts, allowing magma to reach the surface. What is a hot spot? An area where magma rise from the mantle. How does a hot spot volcano form? Over a long period of time, lava flows to the surface and forms new rock. The layers of rock keep adding up to form a volcano. What features form as an oceanic plate moves across a hot spot? A series of volcanic mountains form. It can be a group of islands, too.

Map Homework Observations? Where are earthquakes and volcanoes located? Did you see a pattern?

Pg. 205 Measured from the bottom of the Pacific Ocean, the Big Island of Hawaii is the largest mountain on Earth. The island is made up of massive volcanoes. One of these volcanoes, Mount Kilauea (kee loo ay uh) erupts frequently and produces huge amounts of lava. At a temperature of around 1,000°C, lava from Mount Kilauea is very dangerous. Yet most of the time, the lava moves slower than a person can walk—about 1 kilometer per hour. Some types of lava move much more slowly— less than the length of a football field in an entire day. How fast lava flows depends on the properties of the magma from which it formed.

Mount Kilauea

1/9/13 Properties of Magma (7.2) Vocabulary Physical Property - characteristics that can be observed or measured without changing what the object is made of Density, hardness, melting point, magnetism Chemical Property – Substance ability to burn, combine or react with another substance Things to look for: Changing color, produces gas, forms a new substance Example: silver jewelry turning dark color (reaction with oxygen) Viscosity – (physical property) how well a liquid flows High viscosity = slower flow Low viscosity = flows easily What is an example of something with high viscosity What causes high or low viscosity? How the particles in the liquid move – how much friction!

Viscosity depends on silica content and temperature Magma Melted mantle rock Viscosity depends on silica content and temperature Silica Content – oxygen + silicon more silica = higher viscosity = light colored lava (rhyolite) Less silica = low viscosity = dark colored lava (basalt) Temperature – Viscosity increases as temperature decreases Cold temperature -> high viscosity -> thicker Temperature of magma = 750°C to 1,175°C Pahoehoe – fast moving lava, high temperature, low viscosity Wrinkled Aa – cooler and slower moving magma Rough and jagged Example of pouring honey Pahoehoe (pah hoh ee hoh ee) aa (ah ah)

Rhyolite

Basalt

Video and Demonstration Video – Yellowstone National Park hot spot Demonstration – Understanding viscosity

Homework Pg. 205 – 208 Questions on pg 208 #1-3

Viscosity Lab