Sink Hole

-glossary-

-collapse : (v) to fall or drop in a state of unconsciousness
-potholes : (n) a roughly circular hole worn in the bedrock of a river as pebbles are swirled around by water eddies
-drought : (n) a prolonged lack of rainfall
-funnel : (n) a tube with a cone-shaped opening through which liquid, etc can be poured into a narrow-necked container
-limestone : (n) any of various sedimentary rocks composed mainly of CALCIUM CARBONATE, used as a building material and in iron smelting, cement manufacture
-solubility : (adj) denoting a substance (a SOLUTE) that is capable of being dissolved in a liquid
-unconsolidated : (ad) not become solid
-ravel : (v) to tangle (threads, fibres, etc) or (of threads, fibres, etc) to become entangled
–k Karst : (n) denoting the characteristic scenery of a limestone region, including underground streams, gorges, etc

[Karst topography: a landscape shaped by the dissolution of layers of soluble bedrock characterized by a large number of holes and caves]

-topography : (n) the study and description of the physical features of an area, for example its hills, valleys, or rivers, or the representation of these features on maps
-prevalent : (adj) a condition, practice, or belief

-Sink Hole-

Underground rock melting or collapse of the cave is in an existing pit is formed forms potholes.
L As long as the drought continues or excessive pumping of groundwater water level down to the ground can not handle the weight of the cave to collapse was caused by, form a funnel-shaped or cylindrical. Such as limestone r Rock, such as limestone,  is with very high solubility distribution can be seen in the area. [1]

Sinkhole in the process of forming the bedrock of the entire roof suddenly collapses into underground phenomenon stoping, unconsolidated material moving as slowly as slowly collapsing under the vertical cave is raveling phenomenon. Some sink holes can be generated by the disturbance. There were so many caves and sink holes, large and small closed-basin water type is characterized by discrete and unique k Karst topography that is formed, particularly the size and shape prevalent that many sinkhole Sinkhole is called k Karst. [2]

The first picture is a sinkhole in England, then the next is a picture of a slowly subsiding one.

(sink hole 6)
This is a sinkhole happened in the ocean, the water is sucked into a hole.

(sink hole 7) (sink hole 8.)
Some of the sinkhole has a lake, the depth of the lake are known to be huge deep.

Some of the sink hole video.

[http://www.youtube.com/watch?v=Oi5LN6MIsiw&feature=player_embedded]

-References-

texts
[1] http://bygod.blogist.net/30087955501
[2] http://blog.naver.com/ntam2010?Redirect=Log&logNo=150092574276

pictures
http://www.cyworld.com/ktftelecom/3960846
http://blog.naver.com/o_olms?Redirect=Log&logNo=120108463742
http://blog.naver.com/jang9431?Redirect=Log&logNo=120108320566

-Discuss question-
1.Someone paid the money to you. Instead, you should enter in the sink hole. What is your choice? Why do you think? If someone offered you money to go into a sink hole, would you go? Why or why not?
2.Sink hole, other than a natural disaster, which can be viewed as valuable? Is there anything good about sinkholes? What?
3.Do you think sink holes shape of the rounded appearance of with rounded shapes exist? Why or why not?

[Class 100, Group 2]