Group Size: Up to 32 students Two 45-60 minutes Introduction: Water is a dynamic and strong force. It can slowly break a part rock and rot away steel. Water from the air and ground help to transform the surface of the Earth through a process called erosion. There are a few types of erosion: physical, chemical etc. This lesson focuses on physical and chemical erosion.
This lesson is meant to help draw connections between physical geology and aspects of the weather and water systems. Learning Objectives:
Water helps to shape the surface of the planet by breaking away materials and washing it into the oceans.
Guiding Questions: How does water from the atmosphere help to break down mountains? Can water underground erode away the land as well? Materials:Activity 1 Molded Gelatin (set up day before activity) Plastic or Paper Cups Sand and Gravel (optional) Hot Water Cold Water Spray Bottles Chaffing Dishes or other large basin Screen or peg board Activity 2 Sugar Cubes (set up day before activity) Confectioner’s Sugar Q-Tips Hot Water Dropper (optional) Prep one or more days prior to lesson:Activity 1:Heat up unflavored gelatin and mixing optional sand and gravel. Pour into plastic or paper cups and place in refrigerator to cool and set. Activity 2: Mix water and confectioner’s sugar into a paste. Use the paste to construct a false karst landform, with or without “air” pockets. Activity 1: Students will work in pairs or a small group. Have students place a screen or peg board over their basin. Place the gelatin mountain on top of this screen. Students may at this time begin to spray down the gelatin mountain with warm water. Have students note how fast or slow the gelatin is weathering away.
Ask student to then pour cold water and the warm water over the gelatin mold. Have students note whether it is weathering away faster of slower. Answer the following questions: Does a little bit of rain make much of a difference? What happened when you poured a lot of cold water over the gelatin mountain? What happened when you poured a lot of warm water over the gelatin mountain? How may this be similar to what happens on Earth? Discuss the findings with the class. Activity 2: Expanding on the ideas of warm water versus cold water in weathering, and also taking note of the idea that the more water raining down the faster the erosion, have each group pick one of the following variables for their experiment. •Very little drops of cold water •Very little drops of warm water •A lot of cold water •A lot of warm water After each group has chosen a variable for this erosion activity, have students place their karst formations on top of the screened basins and begin their experiments. Students who chose a lot of warm water should have the greatest results.
Water should work its way in and around the weak points in the karst formation and should begin to form tunnels and caves. Conclusion and Wrap Up: Have the groups share their results with the class. Reflect on the ideas of erosion on mountains and also weak ground systems like karst formations. Have students add to their LINK. Vocabulary to note: Karst Formations Chemical Erosion Physical Erosion New York Scope and Sequence:Intermediate and High School Science Standards Physical Setting: Key Idea
1.2, 1.2j, 2, 2.1c, 2.1r - 2.1u, 2.2a - 2.2c