Script Idea

Today's topic--weathering and erosion

What is topography? Do the students know the names of any topographic features in the world? (Mountains, valleys, canyons, etc.). Can they think of any unique topography in Pensacola? (Hills, bluffs, beaches, marshes.)

Where do our beaches come from, where is the beautiful white sand from? Quartz from the Appalachian Mountains. How do we get the quartz from the Appalachian Mountains? Weathering and erosion. Let's explore. Demonstrate the weathering of the sugar cubes by the pebbles. Put a few sugar cubes in a plastic cup with a few pebbles. Put on the lid. Shake. What happens to the sugar? What causes the change?

How does the quartz from the mountains get to Pensacola? Water. Why does it stop just as it gets to the Gulf? (Water loses energy due to collisions with Gulf water and the potential energy is zero at sea level so you have no new generation of kinetic energy.)

Now, what factors affect our beach? Wind and water. Let's investigate how wind affects our beaches, since water would be messy....

Demonstrate the barrier island activity. What do the different things symbolize in this model? (Sand is beaches, empty box space is water, blowing is wind.) What does the wind do to the sand? Our barrier islands aren't just sand. What other things are on our beaches? Houses, plants, fences, seawalls (we don't really have them on the beach, but they are on the bayous. why aren't they on the beaches?).

Let's find out how those things affect the natural changes of the beaches. Present the assorted objects to put in the sand, explaining what each symbolizes. Have the student groups choose which objects they want. Have them hypothesize what will happen to the sand near each object. Caution the students to only blow from one direction. Ask the students in advance what kind of data they will record. (A sketch of the final outcome, perhaps.)

If students wish to investigate further, they could explore how the topography of the beaches (the dunes, the sound) affect the mainland. Also, they might discuss how a hurricane affects the topography of the island, with or without dunes, houses, etc.

Basic procedure
Key Knowledge
Science Background
Script Idea
Barrier Islands
Alternate Ideas
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