Time: Four fifty minute classes
Setting: computer lab or classroom with Internet accessible computers
Setting: computer lab or classroom with Internet accessible computers 1.
Sinkholes are a common feature of Florida’s landscape. They are one of many kinds of karst landforms, which include caves, disappearing streams, springs, and underground drainage systems. All of which occur in Florida. (Karst refers to the characteristic terrain produced by erosion associated with chemical weathering and the dissolution of limestone or dolomite, the two most common carbonate rocks found in Florida.) Dissolution of carbonate rocks begins when they are exposed to acidic water. Most rainwater is slightly acidic and usually becomes more acidic as it moves through decaying plant debris. There are 400 new sinkholes reported in Florida each year. Place The Florida Aquifer transparency on the overhead. Limestone in Florida is porous, allowing the acidic water to percolate through the strata, dissolving some limestone and carrying it away in solution. Over eons of time, this persistent erosion process has created underground voids and drainage systems in much of the carbonate rocks throughout the state. Too much groundwater can cause problems. As water flows from the soil to the limestone layer, it wears away parts of the rock. Water gathering in the empty areas can become underground streams and pools. If an empty area gets large enough, the ground can cave in. This leaves a bowl-shaped hole called a sinkhole.
Geologists estimate that Florida’s oldest sinkhole, called the Devil’s Millhopper, located in Gainesville, was formed nearly 20,000 years ago. It runs 120 feet deep and has sides covered by vegetation. Today, visitors may descend a 236 step staircase to the bottom of the hole. Go to website:
Click on all the graphics. Look at the vegetation.
Hurricanes are formed over tropical oceans where there are warm waters, humid air and converging winds. It takes a lot of energy for a hurricane to be created, not to mention just the right conditions. Hurricanes start out as a group of storms that begin to rotate when they encounter converging winds. These storms create violent seas, stirring up even more water into the air in the form of vapor. The water vapor rises very quickly, rotating with the storms, and helping to increase the wind speed. The storms begin to organize, holding themselves together and forming a central rotation point of low pressure. When this occurs, and sustained wind speeds reach 74 mph, the storms become a hurricane.
A trench in the earth’s soul.
Damp, mysterious, dark
A very distinct landmark.
A very dangerous place to be
Could be part of an underground sea.
Falling, crumbling, sighing
The awful sound of crashing