Geology Volcanoes&Earthquake Assignment8 Assignment

Geology Volcanoes&Earthquake Assignment8 - Assignment Example An inevitable tide was moving red-hot lava onshore and people watched helplessly. However, a small crew led by Thorbjorn Sigurgeirsson squirted the lava in the front with fire hoses producing vapors of steam (John A. McPhee. 102). The courageously watered and cooled the advancing lava until they stopped the lava flow (John A. McPhee. 107) The gas content in magma or lava determines whether a volcanic eruption will be explosive or effusive. These gases include sulfur dioxide, water vapor and carbon dioxide. A gas highly dissolves in magma that is situated deep underground, where pressure is very high. The rate of dissolution decreases as the lava moves up to the earth’s surface due to reducing pressure, thus, the gas form bubbles that drag magma to the surface. The eruption is explosive if more bubbles form and effusive when there are few bubbles. A cinder cone forms when lava with more bubbles is expelled and cools in the air (Gates and Ritchie p.157). Magma comprises of solid minerals, liquid rocks and gas. The amount of the silica mineral in lava or magma determines a volcanic rock to be formed. The mafic rocks include all basalts and some andesites: have lower silica content, intermediate rocks such as some dacites and most andesites with intermediate silica content, and silicic rocks. Silicic rocks have higher silica content and include all rhyolites and some dacites. Apart from silica, volcanic rocks have other minerals such as titanium, aluminum, iron, manganese, magnesium, calcium, sodium, potassium, and phosphorus. These chemicals are mix with oxygen to form their respective chemical compounds (Park, 2001, p. p.177). A magma viscosity determines a volcano shape, texture and shape of lava, and whether a volcano erupts effusively or explosively. A less viscous lava forms shield volcanoes with wide sloping sides while more viscous lava builds conical volcanoes with steep sides.

When Volunteerism Isn't Noble Essay Example | Topics and Well Written Essays - 750 words - 1

When Volunteerism Isn't Noble - Essay Example Her disagreement with the school board on trading voluntary hours with credits did not stop her from offering free service. This is because she believes that volunteering in one’s community is of worth and fundamental. She disagrees with mandatory volunteering because it is not genuine. People in such programs are forced to engage in voluntary services to satisfy goals that could be educational. For example, in Lynn’s school, students were compelled to complete hours of community services to get their respective diplomas. Lynn refuses to comply with mandatory volunteering in her school because of several reasons. The first reason that inspires her refusal to comply with compulsory volunteering is its equivalence to blackmail. She does not understand why the president would approve any programs that force students to volunteer before they attain their grades. Her decision to sue Liberty High was attributable to the fact that obligatory volunteerism program was faulty. Sh e noticed that other students joked about it while others exaggerated the number of hours they worked (McWhorter 19). I do not agree entirely with Lynn Steirer’s ideas on volunteering. Volunteering should not be liberal because it affects the entire volunteering process. Volunteering has desirable results when people are forced to participate, for example, by being given hours that they need to satisfy. Sometimes people need to be forced before they realize the significance of volunteering in both their lives and communities. Mandatory volunteering is positive especially to students because it could make students responsible. During the volunteering process, students notice that they are passionate about volunteering making them responsible students. They could be unaware of institutions that allow them to offer their free services. This suggests that mandatory volunteering exposes them