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Lesson Plans Library 9-12 > Physical Science
Nonmetals
Nonmetals
Grade level: 9-12 Subject: Physical Science Duration: Two class periods
 



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Objectives
Students will
  • Describe the chemical processes involved in cave formation.
  • Explain the chemistry behind the development of at least two features found in caves.
  • Identify the elements involved in cave formation on the periodic table of the elements.
  • Describe how these elements combine to form the compounds that contribute to the
    formation of caves.
Materials
  • Nonmetalsprogram
  • Computer with Internet access
  • Poster board
  • Markers and colored pencils
  • Index cards
  • Tape
  • Copy of the periodic table of the elements
Procedures
  1. Begin the lesson by asking students if they have ever visited a cave. If so, ask them to write down any distinctive features they remember from their visit. Then tell students to put the paper away until the end of the lesson.

  2. Have students watch the segment "The Chemistry of Caves" in the programNonmetals. Ask students to focus on limestone caves and how they form, as well as on how unique features found inside the caves form.

  3. Divide the class into pairs. Tell each pair to either draw a picture of a limestone cave or find a picture online. Then ask students to develop a detailed caption describing the chemical processes involved in the formation of the cave. Their cave image should include at least two unique features, such as stalactites and stalagmites, and students should write a description
    of how these features form as well. Students can write their descriptions on index cards and tape them below their image.

  4. Give students time in class to work on their projects. The Web sites below provide information.

    Cave Formation
  5. For your information, below is a brief description of how limestone caves and two features inside caves form.
    • Limestone caves form when water seeps into cracks in the rock. Because the water has been exposed to carbon dioxide from the air and soil, the water forms a mild acid, called carbonic acid. Over a long period of time, the carbonic acid causes the rock to dissolve, resulting in the formation of a cave.
    • As the water travels through the cave, it loses the carbon dioxide that has been dissolved in it. As a result, the water cannot hold as much of the dissolved calcium. The excess calcium then falls out of the solution and ends up on the cave walls and ceilings as the mineral calcite. The result is interesting formations inside the caves. These formations are called speleothems.
    • Stalactites are speleothems that hang from the ceiling of the cave. Stalagmites grow up from the floor of the cave. Other formations, called popcorn, develop on cave walls. As water drips out of the walls, the calcite falls out of the solution and clusters on the cave walls, creating shapes that resemble popcorn.
  6. During the next class period, give students a little more time to finish their captions and drawings. Then ask for volunteers to share their ideas about how caves and their unique features form.
  7. Refer students to the periodic table of the elements. Ask for volunteers to identify the elements involved in cave formation. Students should now know that hydrogen, oxygen, and carbon ? all nonmetals ? combine to form the compounds that lead to the formation of caves. Ask students to name the compounds and the elements that caves are made from. If students need prompting, remind them that water and carbon dioxide are involved in cave formation. (Hydrogen and oxygen combine to form water. Carbon and oxygen combine to form carbon dioxide. Carbon dioxide and water create the acid that causes caves to form.)
  8. Conclude the lesson by asking students to look at the ideas about caves that they recorded before they began work on this project. If students had visited a cave, do they now understand how its features formed? If not, can they now explain to family and friends how nonmetals combine to form limestone caves?

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Evaluation
Use the following three-point rubric to evaluate students' work during this lesson.
  • Three points: Students demonstrated a clear understanding of the chemistry behind the formation of caves and their unique features; identified all the nonmetals on the periodic table that combine to form the compounds involved in the formation of caves; were able to identified all the compounds involved in cave formation.
  • Two points: Students demonstrated a satisfactory understanding of the chemistry behind the formation of caves and their unique features; identified most of the nonmetals on the periodic table that combine to form the compounds involved in the formation of caves; identified most of the compounds involved in cave formation.
  • One point: Students demonstrated a poor understanding of the chemistry behind the formation of caves and their unique features; were not able to identify the nonmetals on the periodic table that combine to form the compounds involved in the formation of caves; were not able to identify the compounds involved in cave formation.

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Vocabulary
limestone cave
Definition:An underground opening formed when water, mixed with carbon dioxide from the air and soil, seeps into limestone rock, causing the rock to dissolve; this process takes place over very long periods of time
Context:Mammoth Cave in Kentucky is an example of a limestone cave that has a large underground chamber and many tunnels and passageways.

nonmetals
Definition:A group of elements, many of which are gases at room temperature, that make up many of the materials found on Earth
Context:Oxygen is an example of a nonmetal that is highly reactive and can combine with almost every other element on Earth.

periodic table of the elements
Definition:An organization of Earthís elements arranged according to atomic number, the number of protons each elementís nucleus contains
Context:Dmitri Mendeleev, a Russian scientist, developed the first periodic table of the elements in 1869, and it was organized according to the atomic mass of each element.

speleothem
Definition:A distinctive feature that forms in a cave
Context:Speleothems encompass a wide variety of cave formations, including popcorn and flowstone.

stalactite
Definition:A type of cave formation that forms from the ceiling of a cave and hangs down
Context:Stalactites look like icicles, but instead of forming from water, they form from the mineral calcite.

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Academic Standards
Mid-continent Research for Education and Learning (McREL)
McREL?s Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education addresses 14 content areas. To view the standards and benchmarks,click here.
This lesson plan addresses the following national standards:
  • Physical Sciences: Understands the structure and property of matter
  • Language Arts - Viewing: Uses viewing skills and strategies to understand and interpret visual media

National Academy of Sciences
The National Academy of Sciences provides guidelines for teaching science in grades K?12 to promote scientific literacy. To view the standards,click hereto visit the Web site.
This lesson plan addresses the following national standards:

  • Physical Science: Chemical reactions
  • Physical Science: Structure and properties of matter

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