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Stormy WeatherStormy-Weather

  • Subject:
  • |
  • Grade(s): 6-8
  • |
  • Duration: Two class periods

Lesson Plan Sections

Objectives


Students will understand the following:
1. Static electricity is the cause of lightning.
2. Lightning forms because of an accumulation of electrical charges inside a cloud due to friction from dust, ice, and water droplets.
3. The bottom of a cloud becomes negatively charged and discharges a lightning strike when enough charge has built up.

Materials


Groups will need the following materials for their demonstrations:
Group 1: ground pepper; plastic utensil, such as a knife or a comb; wool or nylon cloth
Group 2: plastic comb, piece of wool or fur, metal doorknob
Group 3: two rubber balloons
Group 4: plastic combs, bowl of puffed rice

Procedures


1. Review with your students what they know about cloud formation, thunder, and lightning storms. Tell them they are going to perform a series of simple demonstrations that will show how an accumulation of electrical charges inside a cloud causes a lightning strike.
2. Divide your class into small groups. Have each group perform one of the following demonstrations for the rest of the class.
3. Demonstration 1:
  1. Spread grains of ground pepper on a small area of a desktop.
  2. Vigorously rub a plastic utensil with a wool or nylon cloth to produce a negative charge.
  3. Hold the utensil about 1 inch over the mixture and observe what happens. (The utensil will pick up the pepper.)
4. Demonstration 2:
  1. Darken the room as much as possible.
  2. Rub a plastic comb with a piece of wool or fur.
  3. Hold the comb near a metal doorknob.
  4. Observe what happens. (Students will see tiny sparks.)
5. Demonstration 3:
  1. Blow up two balloons and rub them on your sleeve.
  2. Darken the room as much as possible.
  3. Rub the two balloons together.
  4. Observe what happens. (Students will see tiny sparks.)
6. Demonstration 4:
  1. Run a comb through your hair (only one student should use each comb).
  2. Put the comb into a bowl of dry puffed rice.
  3. Observe what happens. (Grains of rice will stick to the comb; after they lose their charge, they will fall off.)
7. After each group has performed its demonstration, explain that in each case, friction created a buildup of electrons, causing an electrical charge. This is known as static electricity. Tell students that in a storm cloud, friction from dust, ice, and water droplets produces an accumulation of charges, as did the friction in each of the demonstrations. It is this static electricity that causes lightning.
8. Have each student write a paragraph describing the demonstration his or her group performed and what group members observed. Paragraphs should be accompanied by illustrations and labeled diagrams. Invite students to share their explanations and illustrations.
9. Share with your class the following explanation of lightning from Simple Weather Experiments with Everyday Materials, by Muriel Mandell (Sterling Publishing Company, 1990): The violent air currents in thunderclouds move different-sized drops and dust particles at different speeds. Those of the same size and with similar amounts of electricity get concentrated in the same part of the cloud. A very high positive electrical charge is formed in the cold higher parts, while near the ground the thundercloud usually is negatively charged. The big difference between the charges at the top and bottom of the cloud creates a powerful voltage or electric pressure. This "push" sends a flash of lightning streaking through the cloud between those parts with opposite electric charges.

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Adaptations


Adaptations for Older Students:
Rather than explain the causes of lightning to the class, have each student do research on the causes of lightning and write a brief paragraph explaining the physics behind a lightning strike.

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Discussion Questions


1. Examine the development of a lightning bolt from small charge to discharge. Explain the phases in the life of a lightning bolt.
2. Develop an idea for capturing and using lightning as a power source. What areas of the world would most benefit from such a device?
3. Explain what type of structure you would choose as shelter during a lightning storm. Include reasons for your choice.
4. Keeping in mind that Ben Franklin didn't invent or discover lightning, write a letter from Mr. Franklin to George Washington detailing your experiment and the things you learned. Explain to Mr. Washington how your lightning bells work and of what use they have to households in the new country of America.
5. Mary Shelley speculated that a person could be made from parts of dead people. In her book Frankenstein , a mad doctor assembled people parts into a personlike shape, then brought it to life with lightning. Knowing what you now know about lightning, debate whether or not this would really work.

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Evaluation


You can evaluate your students on their descriptions using the following three-point rubric:
  • Three points: paragraph accurately describes the demonstration and observations; paragraph clear and well organized; writing free of errors in grammar, usage, and mechanics

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  • Two points: paragraph adequately describes the demonstration and observations; paragraph somewhat lacking in clarity and organization; some errors in grammar, usage, and mechanics

  •  
  • One point: description of demonstration and observations sketchy or inaccurate; paragraph unclear and disorganized; many errors in grammar, usage, and mechanics

You can ask your students to contribute to the assessment rubric by determining what information should be included in the paragraphs.

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Extensions


The Truth about Lightning
Invite your students to develop lightning-facts brochures for elementary-age children. They should illustrate the brochures with as many drawings as they think are necessary to educate younger children about the hazards associated with lightning. When the brochures are complete, have students present them to a local elementary school class along with a short presentation covering the major points of the brochure. Students should include facts about the following topics in their brochures:
   a. Cloud formation
   b. Evolution of a lightning bolt and electrical charges
   c. Lightning production
   d. Temperature of a lightning bolt
   e. Lightning conduction
   f. Thunder
   g. Scientific research on lightning
   h. Lightning safety

Cloud Maker
In this activity, students will create and study an artificial cloud. Have them follow this procedure (or demonstrate it to them): Pour a cup of cool water into a clear 2-liter soda bottle with the label removed. Cover the bottle, and shake it vigorously for a minute or so to saturate the air inside the bottle with water. Open the bottle, and pour out the water. Carefully light a wooden match and blow it out gently. Insert the match into the open bottle so that smoke goes into the bottle. Cap the bottle tightly. Squeeze the bottle as hard as you can and hold it for several seconds. Let it go, and you'll have a cloud! Shine a flashlight through the bottle, and hold a piece of black paper behind it to see the particle motion.
 
Have students write a description of cloud formation. Have them include how this demonstration was similar to that of real cloud formation. What practical applications might a large-scale cloud maker have?

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Suggested Readings


The Electrical Nature of Storms
Donald R. MacGorman and W. David Rust. Oxford University
This current work covers atmospheric electricity and how it is made manifest in storms.

Storm Chaser: In Pursuit of Untamed Skies
Warren Faidley. Weather Channel, 1996.
The logistics of tracking dangerous storms, including lightning, thunderstorms, tornadoes, and hurricanes, is covered in this publication by a meteorological leader in the media. Includes color illustrations.

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Links


Theatre of Electricity
Provides information, great graphics, and a quiz on lightning and electricity.

Lightning and Atmospheric Electricity at the GHCC
Great scientific information on lightning. Be sure to check out Lightning Primer.

National Lightning Safety Institute
Lightning safety facts, Ben Franklin quotes, and lightning questions answered.

Lightning Information Index
Facts about lightning and weather information.

Project Safeside: Lightning Safety
Explains the ins and outs of lightning safety.

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Vocabulary


Click on any of the vocabulary words below to hear them pronounced and used in a sentence.

speaker    convection current
Definition: The transfer of heat or other atmospheric properties by massive motion within the atmosphere, especially directed upward.
Context: Strong convection currents lift smaller droplets higher and higher, and in the cold reaches of the upper atmosphere they freeze into ice crystals.

speaker    sheet lightning
Definition: Lightning in diffused or sheet form due to reflection and diffusion by the clouds and sky.
Context: Ninety percent of all lightning never touches the ground—it occurs inside the thunder cloud or jumps from cloud to cloud. A single bolt can illuminate an entire cloud from the inside. We call this sheet lightning.

speaker    sprites
Definition: Massive but weak luminous flashes that appear directly above an active thunderstorm system and are coincident with cloud-to-ground or intracloud lightning strokes.
Context: Sprites are immense. They shoot up from the top of a 12-mile thundercloud to heights of 60 miles or more.

speaker    step leaders
Definition: Thin, luminous feelers, caused by electrical breakdown in a cloud, that move in short bursts, or steps, and precede lightning strikes.
Context: Lightning begins in the negatively charged region at the base of a cloud. Here, thin, barely luminous feelers called step leaders zigzag through the cloud.

speaker    thunder
Definition: The sound that follows a flash of lightning and is caused by sudden expansion of the air in the path of the electrical discharge.
Context: This explosive heat produces a massive, deafening shock wave—thunder.

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Standards


This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of theMid-continent Research for Education and Learningin Aurora, Colorado.
 
Grade level: 6-8
Subject area: science
Standard:
Understands energy types, sources and conversions, and their relationship to heat and temperature.
Benchmarks:
Benchmark (6-8): Knows that energy comes in different forms, such as light, heat, chemical, nuclear, mechanical, and electrical.

Benchmark (6-8): Understands that energy cannot be created or destroyed but only changed from one form to another.

Benchmark (6-8): Knows that electrical circuits provide a means of converting electrical energy into heat, light, sound, chemical, or other form of energy.

Benchmark (9-12): Knows that all energy can be considered to be either kinetic energy (energy of motion), potential energy (depending on relative position), or energy contained by a field (electromagnetic waves).

Grade level: 6-8
Subject area: science
Standard:
Understands basic features of the Earth.
Benchmarks:
Benchmark (6-8): Knows that clouds, which are formed by the condensation of water vapor, affect weather and climate. Some do so by reflecting much of the sunlight that reaches Earth from the sun; others hold heat energy emitted from the Earth's surface.

Benchmark (9-12): Knows that weather and climate involve the transfer of energy in and out of the atmosphere.

Grade level: 6-8
Subject area: geography
Standard:
Knows the physical processes that shape patterns on Earth's surface.
Benchmarks:
Knows the consequences of a specific physical process operating on Earth's surface (e.g., effects of an extreme weather phenomenon such as a hurricane's impact on a coastal ecosystem, effects of heavy rainfall on hill slopes, effects of the continued movement of Earth's tectonic plates).

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Credit


Frank Weisel, earth science teacher, Tilden Middle School, Rockville, Maryland.

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