Earth Science Bellringer Get out your “Renewable & Nonrenewable Resources Lab” Turn it in to the Basket

Everyday is a Holiday! National Goof –off day!

II. Weathering & Erosion 8min

A. Weathering and Erosion Is the break-up of rock due to exposure to the atmosphere. is the removal and transport of earth materials by natural agents

B. Two types of Weathering 1. Mechanical 2. Chemical Takes place when rock splits and breaks into smaller pieces of the same material with out changing its composition. Takes place when the rocks minerals are changed into different substances http://www.history.com/shows/how-the-earth-was-made/videos/erosion

C. Mechanical Weathering Examples -When water seeps into cracks of rocks then freezes (water volume expands 10% when frozen) 1. Ice wedging

2. Wetting & Drying 3. Small Plants 4. Small Animals 5. Sheet Jointing 6. Exfoliation -Repeated wetting and drying of rock is very effective at breaking up rocks that contain clay. -Roots grow down into tiny cracks expanding and chipping the rock apart. -Earth worms, ants and rodents dig holes in the soil exposing the under ground to air and water. -When large masses of rock are lifted to form mountains and the surface rock removed… this reduces the pressure on the rock under-ground so the rock begins to expand. -When large sheets of loosened rock break away from a rock outcrop.

D. Chemical Weathering Examples Reaction of H2O & other substances Reaction of oxygen & other substances - Dissolves minerals to create undergound caverns. D. Chemical Weathering Examples 1. Hydrolysis 2. Oxidation 3. Carbonic acid

Feldspar +Water = Clay Feldspar A Clay Cliff

Review (12min)

Chemical Weathering The process that breaks down rock through chemical changes. The agents of chemical weathering Water Oxygen Carbon dioxide Living organisms Acid rain

Water Water weathers rock by dissolving it

Oxygen Iron combines with oxygen in the presence of water in a processes called oxidation The product of oxidation is rust

Carbon Dioxide CO2 dissolves in rain water and creates carbonic acid Carbonic acid easily weathers limestone and marble

Living Organisms Lichens that grow on rocks produce weak acids that chemically weather rock

Karst Topography A type of landscape in rainy regions where there is limestone near the surface, characterized by caves, sinkholes, and disappearing streams. Created by chemical weathering of limestone

Features of Karst: Sinkholes

Features of Karst: Caves

Features of Karst: Disappearing Streams

Weathering & Erosion Review In your comp book … Complete the following “Weathering & Erosion” review -Pg. 244 #1-5 Analyzing Data (red text)

Get a text book … turn to page 238-244. Video: Weathering and Erosion. Alka Seltzer packets next class.

Sink Holes

Chemical Weathering Lab Objective: Model the rate of chemical weathering using temperature and surface area. Hypothesis: (what is your educated guess about how different temperatures and varied surface area may affect the rate of weathering). Guiding Questions What is surface area? How does it affect the rate of weathering? What is climate? How might that affect the rate of chemical or mechanical weathering?

Which has more surface area? A 1 ton pile of rocks or a 1 ton rock? We are going to use Alka-Seltzer tablets as our ‘Rock’ for this lab.