- Creation Date: September 21, 2012
- Academic Subject:
In this video we explore the different processes that are constantly at work to change and remodel our earth’s surface. We’ll first pose a question asking: since the Earth is over 4 billion years old (showing pictures of really old, seemingly static rocks, dinosaur fossils, and buildings), is the surface we live on also that old? The answer is NO! But why?
We’ll explain that there are several processes hard at work to constantly remodel the planet we call home, demonstrating in the lab concepts behind each process that students can relate to:
• SLOW Processes: Erosion and weathering:
o Erosion and weathering: we will focus on the concept of wind and water erosion (material transport due to friction/movement) and weathering (breaking down of materials due to contact with Earth’s atmosphere) Demonstration: we will demonstrate erosion by placing gravel/sand on a declined slope, and we will run water and wind over the surface with time-lapse video to show the gradual movement of particles down the slope. We will demonstrate chemical weathering using either water or a weak acid to dissolve a mineral (Halite, or rock salt). Alternative weathering demonstration: mechanical weathering using freezing/thawing (ice cubes).
• FAST Processes: Landslides, volcanic eruptions, and earthquakes
o Volcanic eruptions: we will talk about the Pompeii eruption and show footage of lava flows and ash clouds (if possible). Demonstration – we’ll make a baking soda / vinegar volcano, and force it to bubble over and affect the surrounding area. Maybe use silly string or other aerosol product to simulate ash cloud?
o Earthquakes: we will talk about “recent” mega earthquakes (San Francisco 1906, Japan 2011, with pictures/video if possible). Demonstration – we’ll take two pieces of cracker bread, force them against each other under pressure, and demonstrate fault lines/cracks/destruction as they crush against each other
o Landslides: we will talk about what a landslide is and the important factors in a landslide (gravity, water content, slope, vibration/lack of vegetation, etc.). Demonstration – we will put sand/gravel on a steeply declined slope, and show how the addition of water/increasing slope, among other things, leads to mass-movement of material, and thus, destruction of a nearby miniature city!