06/11/2015 End of Year Reflection
06/19/2016 End of Year Reflection II
The book Chemistry on a Budget contains inexpensive chemistry labs that are useful with easy to obtain materials.
There are two versions of each lab, one with a ten-question conclusion and one with directions for a full lab report. This way the teacher has the option! Each lab is two pages to allow for one two-sided handout.
You can buy this lab book for $23 at amazon.com or lulu.com. It will take 1-2 weeks to get to you -- It’s a great resource that you can examine and labs you can test over the summer!
*Some of you have already purchased my lab book – be sure to check out Page 141 !
“There's an area on the west side of the icy continent called the West Antarctic Ice Sheet, and last January , scientists found a 300,000-square-mile portion of its perimeter was melting. That's an area roughly two times the size of California, covered in slush.
According to recent research published in Nature Communications, the melt was caused by an unusually strong El Niño event around January 2016.”
“The rift on the ice shelf attached to the northernmost part of the Antarctic Peninsula first appeared in August 2014 and has been growing steadily, including more than 17 miles since December of last year.
When the huge chunk of the shelf finally breaks off — and researchers are all but certain it will — it will be one of the largest ice calving incidents since they began studying ice shelves around the southern continent two decades ago. “
“In January 2016, over the course of just a few weeks, a 300,000 square mile chunk of the West Antarctic ice sheet started turning to slush, in one of the largest melt-outs ever recorded. Scientists with the ARM West Antarctic Radiation Experiment (AWARE), who reported the epic defrost in Nature Communications last week, believe it was related to the 2015-2016 El Niño. Troublingly, they think massive melts like this could be a harbinger of the future — but more research is needed before we can be sure.
The West Antarctic ice sheet has been called the "weak underbelly" of the Antarctic continent, and for good reason: Its glaciers, which contain enough frozen water to raise global sea levels by at least 3.05m, are shedding mass rapidly as the planet heats up. The prevailing wisdom is that warm ocean waters are weakening West Antarctica's floating ice shelves from below, and causing inland ice sheets to detach from the underlying land surface at their so-called "grounding line." But a recent survey found evidence for ephemeral lakes and river networks across Antarctica, raising concerns that surface melting could also play a significant role in ice sheet disintegration.”
“The biggest driver of the Antarctic heat wave was the super El Niño, then at its peak in the tropical Pacific. It helped rearrange the atmosphere so a high pressure system off Chile’s coast could steer abnormally balmy weather toward West Antarctica. The pattern has played out in other El Niño years, causing similar widespread melt events. “
“A fissure in the Larsen C ice shelf in west Antarctica, the sliver of the continent which points toward South America, has been developing since 2010.
It is now 200km long and up to 5km wide in some parts. It has crept west, in fits and spurts, over the past seven years, but in the past few weeks, events have taken a dramatic turn.”
There are several helpful diagrams on this page, and a useful 2-minute video summary near the bottom of the page.
“Martin O’Leary…of Swansea University, said: ‘It just makes the whole shelf less stable. If it were to collapse there would be nothing holding the glaciers up and they would start to flow quite quickly indeed.’
O’Leary added that while calving is a natural process that happens every decade or so and is not driven by climate change, the disintegration of a major shelf could accelerate the melting of glacial ice linked to warming oceans.”
“[According to] Northeastern's Daniel Douglass, lecturer in the Department of Marine and Environmental Sciences and an expert in glacial geography, to explain why ice shelves form, what causes them to crack, and how they affect the environment.
What exactly is an ice shelf?
An ice shelf is created when a glacier—ice that is moving over land—enters the ocean. The ice will float up and the ocean will flood under, thereby creating the ice shelf. An ice shelf can be anywhere from a hundred to a few thousand feet thick. It becomes progressively thinner toward the outer edge of the glacier. Calving is the process whereby pieces of ice break off the thinner, outer edge of the ice shelf to create icebergs. Ice shelves are different from sea ice, which forms when ocean water freezes. Sea ice is analogous to frozen lakes in winter and is usually less than 10 feet thick.
What role does climate change play in the break-up of an ice shelf? What other factors contribute to its dissolution?
A warming climate can contribute to calving in two ways. First, if the ice shelf is exposed to warmer air above and-or warmer water below, then there will be more rapid melting of the shelf. A thinner ice shelf is weaker than a thick ice shelf, and it is easier for a "through-going," or top to bottom, crack to form. Such a crack allows pieces of ice to break off the front of the shelf. Second, if water formed by the melting of the glacier's snow or ice has accumulated on the surface of the glacier and filled surface crevasses—cracks on the glacier's surface that do not go all the way through—then the water pressure at the bottom of the crevasse can widen and deepen the crack, potentially wedging all the way through the ice shelf,facilitating the calving process.”
“A rapid disintegration of Antarctica might, in the worst case, cause the sea to rise so fast that tens of millions of coastal refugees would have to flee inland, potentially straining societies to the breaking point. Climate scientists used to regard that scenario as fit only for Hollywood disaster scripts. But these days, they cannot rule it out with any great confidence.
Yet as they try to determine how serious the situation is, the scientists confront a frustrating lack of information.”
The key word here is “might”…
It is interesting to observe this phenomenon and its effects.
*This Blog contains several entries that would be helpful to your chemistry classroom. Check out the Topic List to help you to find past Blog entries.
Also, Write To Me about your successes, challenges, or questions in the Chemistry Classroom.
Remember, buying a copy of the lab book Chemistry on a Budget can be very useful to your Chemistry classroom with labs and class article ideas.
Have a great weekend!