Tuesday, October 12. 2021

Today's schedule is CDAB

C/D Blocks Social and Environmental Sciences - Today we are off to the Amara organic farm for our next field study. Arzeena and Neil started Amara Farm in 2012 with a dream to grow healthy food for their community. First came the veggies, and then an acre of blueberries in 2014. The farm received its certified organic status in 2015 and has since earned awards such as, the Land of Plenty Award (2018), and the Comox Valley Record's Best Market Vendor (2019). Mr. Benton will be driving us this time. Be prepared to be outside in the partial to mostly cloudy 15-17℃ air and to work on the farm. Yay. Check out the "Edible Valley" podcast on the Amara Farm and Merville Organics here. 

A Block Criminology - Time to get caught up on Blogs...1. Personal Crime Theory, 2. Is School Dangerous for students and 3. What are the Short and Long term impacts of crime on Victims...After  "Why is violence entertaining"? I'll have you answer the following:

1. What is the attraction of violent films and video games?
2. Is there more violent imagery in media now as opposed to the past (think graphic, realistic visceral)? Why / Why not?
3. What kinds of people are drawn to violent imagery and what kind of violent images draw them to that form of entertainment?
4. What is “morbid curiosity”?
5. Are there any equally satisfying substitutions for violent entertainment?
6. What draws our attention to violent media events (news) that are not intended to entertain?

I Lava you Volcanoes...😍

B Block Physical Geography - Today in class we'll try to understand the five different types of volcanoes, with examples, and see if we can figure out where these beasts are on the planet. We'll take some notes about the five types of volcanoes and we'll also look at the differences between explosive and effusive volcanic eruptions (think silica and gas).

When it comes to liquids, viscosity is a measurement of how thick or flowy it is. When lava has low viscosity, it can flow very easily over long distances. This creates the classic rivers of lava, with channels, puddles and fountains. You can also get bubbles of lava filled with volcanic gasses that burble and pop on the surface of the lava. When lava has a high viscosity, it’s very thick and doesn’t flow very well at all. Instead of rivers of lava, you can get crumbling piles of rock flowing down hill. It can also clog up the volcanic vent and form blocks that resist the flow of lava. Viscous lava will trap pockets of gas within the rock, and not let them pop as bubbles on the surface.

The types of magma produced in the various volcanic settings can differ significantly. At divergent boundaries and oceanic mantle plumes, where there is little interaction with crustal materials the magma tends to be consistently mafic (which is a low viscosity magma). At subduction zones, where the magma ascends through significant thicknesses of crust, interaction between the magma and the crustal rock—some of which is quite felsic (which is a high viscosity magma)

From Geology.com

The primary eruption characteristic used to determine the volcanic explosivity index is the volume of pyroclastic material ejected by the volcano. Pyroclastic material includes volcanic ash, tephra, pyroclastic flows, and other types of ejecta. The height of the eruption column and the duration of the eruption are also considered in assigning a VEI level to an eruption. The VEI scale begins at 0 and goes up to 8, with each step in the scale representing an explosivity increase of 10x. So, a VEI 5 is roughly ten times more explosive than a VEI 4. Two steps of the scale is an increase of 100x in explosivity, so  a VEI 6 is roughly 100 times more explosive than a VEI 4.

Volcanologists classify eruptions into several different types. Some are named for particular volcanoes where the type of eruption is common; others concern the resulting shape of the eruptive products or the place where the eruptions occur. 

In a Hawaiian eruption, fluid basaltic lava is thrown into the air in jets from a vent or line of vents (a fissure) at the summit or on the flank of a volcano. Strombolian eruptions are distinct bursts of fluid lava (usually basalt or basaltic andesite) from the mouth of a magma-filled summit conduit. The explosions usually occur every few minutes at regular or irregular intervals. A Vulcanian eruption is a short, violent, relatively small explosion of viscous magma (usually andesite, dacite, or rhyolite). This type of eruption results from the fragmentation and explosion of a plug of lava in a volcanic conduit, or from the rupture of a lava dome (viscous lava that piles up over a vent). Vulcanian eruptions create powerful explosions in which material can travel faster than 350 meters per second (800 mph) and rise several kilometers into the air. The largest and most violent of all the types of volcanic eruptions are Plinian eruptions. They are caused by the fragmentation of gassy magma, and are usually associated with very viscous magmas (dacite and rhyolite). They release enormous amounts of energy and create eruption columns of gas and ash that can rise up to 50 km (35 miles) high at speeds of hundreds of meters per second. 

For more on the differences between explosive and effusive eruptions see:
San Diego State University "How Volcanoes Work"
Volcano World "Volcanic Gasses"
Science World 2005 "When Mountains Fizz"

and yes...I Lava You Volcanoes!


 check out "super chill dude" on Mount Semeru in Indonesia...