A Hole in the Ozone

Lesson Content

• Lesson Plan Template:

  General Lesson Plan

• Learning Objectives: What should students know and be able to do as a result of this lesson?

  
  
  • Explain the importance of the ozone layer in protecting human life.  
  • Understand the factors contributing to ozone depletion.
  • Explain why the ozone hole was unusually large in 2015.
  • Describe how scientists use technology to study the ozone layer and its fluctuations.
  • Cite specific and relevant text evidence to support analysis of the text.
  • Use various vocabulary strategies to define academic and domain-specific words in the text.
  • Determine the central idea(s) of the text.
  • Construct a written response that clearly establishes the main point(s), contains relevant textual evidence to support the main point, utilizes transitions to maintain flow, effectively uses domain-specific vocabulary, and provides an appropriate conclusion.

   

• Prior Knowledge: What prior knowledge should students have for this lesson?

  
  

  For science:

  • Students should have a general understanding of the layers of the atmosphere. This link provides information on the components of the atmosphere and describes the importance of each layer.
  • Students should have a general understanding of how ozone is formed and the its importance. This link will provide background knowledge for the students if they are not familiar with the chemical reaction for the formation of ozone.
  • Students should be familiar with the reactions involving ozone-depleting compounds. There is some chemistry involved in this idea, and students will likely have had different amounts of exposure to this topic depending on what courses they have previously taken. This link may help students understand the concepts. 

  For literacy:

  • Students should have prior experience utilizing various vocabulary strategies to determine the meaning of unknown words in a text. For this lesson, prior experience in using context clues to determine the meaning of words in a text would be beneficial. In addition, students should have some dictionary skills that will enable them to look up words with multiple meanings and determine the most appropriate meaning based on how a word is used in a text.
  • Students should understand the term "central idea" and be able to distinguish central ideas from key details.
  • "Central idea" means much the same thing as "main idea." The central idea is the author's main point about the topic or topics in a text. The central ideas are the dominant, most important, or chief ideas that emerge from all the ideas presented in a text. Students should be aware that the author can have several main points he or she wants to make about the topic or topics in a piece of writing, and as a result, there can be multiple central ideas in a text, especially in longer more complex pieces.
  • Key, or in other words, important, details in a text help an author support and develop his or her central ideas.
  • Students should be aware of text features that can help them locate and learn information when reading a text. The text features in NOAA's hurricane article include the title, subheadings, photographs, and captions.
  • Students should be able to respond to a writing prompt in a clear, organized manner that includes use of an introduction to establish the main point(s), a body paragraph(s) that support the main point(s) and includes relevant and specific textual evidence, and a conclusion that supports the main point(s).
  • Students should have some awareness that use of transition words or phrases can help a piece of writing flow smoothly from one point or idea to the next.

   

• Guiding Questions: What are the guiding questions for this lesson?

  
  

  1. Why is there concern about the ozone hole expanding?

  • The study of the ozone hole is important because of the role ozone has in protecting Earth from damaging UV radiation from the sun. Not only can it affect humans and cause cancer and other health concerns, it can also damage plants and other life. The larger the ozone hole, the larger the impact on Earth. The ozone hole is primarily caused by human action. The use of ozone-depleting compounds is the primary cause for the increasing changes. Policies have been made to regulate the use of these compounds, but full recovery is not expected until 2070.
    • Misconception: Ozone is naturally created and destroyed in the atmosphere; this is a normal process. However, as the amount of ozone-depleting compounds introduced into the atmosphere increases, this normal balance is unequal and loss of ozone occurs. 

  2. What new information did scientists discover about the status of the ozone hole in 2015?

  • In 2015, the ozone hole was discovered to be larger and lasted longer than in previous years. Due to unusually cooler temperatures, the ozone hole reached the size of 28.2 square kilometers. Cooler temperatures cause higher ozone depletion, and as a result the ozone hole was the size of North America in October of 2015.  Although there is concern about the size of the hole, the data is consistent with variations in ozone depletion based on cold temperatures. Scientists are aware that when temperatures are cooler in the stratosphere, ozone depletion rises.

  3. What technology is being used to study the amount of ozone in our atmosphere?

  • Scientists use balloon-borne instruments to measure the thickness of ozone in the atmosphere. Scientists also use data from satellites that monitor the thickness and distribution of ozone at the South Pole. Satellites also measure the amount of chlorine in the atmosphere because it does damage to the ozone.
  • This link provides information on the ozonesonde, an instrument used to measure the thickness of ozone as mentioned in the article.

   

• Teaching Phase: How will the teacher present the concept or skill to students?

  
  

  1. Ask students: "What is ozone?"

  • Have students brainstorm or write down their first thoughts.
    • Some may say it is a pollutant that can harm us.
    • Some may mention that it is part of the atmosphere.
    • Some may know its molecular formula is O3.                                                                                                                                                                    

  2. Next, ask students: "What is the ozone layer?" "What is its function?"

  • Some may know it is in the atmosphere, but explain that it is specifically found in the stratosphere.
  • Some will know the ozone layer protects us from UV radiation from the sun.                                                                                                                                              

  3. Ask students: "Are you aware there is a hole in the ozone layer?  Do you know what has caused it?"

  • Some may have heard there is a hole but may not know that the hole is primarily over the Antarctic region.
  • Some may know the hole was created by releasing aerosols that contained CFCs and other ozone-depleting compounds into the atmosphere.                                                                                                                                                                                                                  

  4. Ask students: "Do you know that the ozone hole varies naturally over time?  What do you think is the cause?"

  • Students will probably be unaware of the changes in the ozone layer of Antarctica throughout the year. Explain to them several factors can affect this:
    • Cold temperatures naturally deplete the ozone layer.
    • The hole changes seasonally (the lowest levels of ozone occur during the coldest time of the year) and thickens as the atmosphere warms.
    • Long-term measurements of the amount of ozone in the atmosphere also show year-to-year changes.                                                                                                                                          

  5. Explain to students they will be reading an article discussing the state of the ozone layer in the year 2015. The article will provide information about the importance of the ozone layer and how scientists measure the amount of ozone in the atmosphere.

   

• Guided Practice: What activities or exercises will the students complete with teacher guidance?

  
  

  1.  Provide students with their own copies of the article "Annual Antarctic Ozone Hole Larger and Formed Later in 2015."

  • For discussion purposes, the teacher may want to have students number each paragraph.
  • Have students preview the article, looking at the text features, images, and captions.  

  2.  Provide each student with a note-taking guide.

  3. Have students fill out the note-taking guide as they read the text. This can be done individually, in pairs, or in small groups. The teacher should monitor students as they work and provide support and guidance as needed.

  • Note: Based on the needs and skills of the students, teachers can decrease the number of academic or domain-specific vocabulary students will define on the note-taking guide.
  • For academic vocabulary, students will likely be able to use a variety of vocabulary strategies to define the meaning of the words. For domain-specific (in other words, subject-specific) vocabulary, students will typically need to draw on prior knowledge and use a dictionary to define the words.

  How will you check for student understanding? (Formative Assessment):

  • The teacher can circulate around the room as the note-taking guides are being completed and take note of any specific insights or misconceptions that should be discussed with the whole class. The teacher could also take note of any answers that were not text-based and relied on reader background knowledge.
  • Students can present different aspects of their note-taking guides to the class and discussions can be held based on these student responses.
  • Open discussion of the note-taking guide will identify depth and breadth of knowledge as well as identify any misconceptions.
  • Teachers can use the sample answer key at the end of the note-taking guide to help them assess students' answers.

  Common errors/misconceptions to anticipate and how to respond:

  • Students may think ozone is the main reason global warming is occurring.
    • Explain that they are probably thinking of carbon dioxide, a greenhouse gas that has been increasing in the atmosphere due to burning fossil fuels
    • Ozone is the main protection we have against intense incoming UV radiation from the sun. The ozone does not block all of the UV radiation, and that’s why we need to use sunscreen when we go outside. UV radiation causes sunburn and damages the DNA of plants and animals, which could disrupt the food webs.
  • Students may say that because of "ozone alerts," that ozone is bad for us.
    • There is "good" and "bad" ozone. The ozone in the stratosphere is what protects us from UV radiation, while the ozone in the troposphere is considered a pollutant.

   

• Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the lesson?

  
  
  • Provide each student with a copy of the text-dependent questions to complete. Students should be reminded to continually refer back to the text and to use relevant and specific evidence from the text to support their answers.

  Formative Assessment (How will teachers check for understanding?):

  1. Teachers can check students' understanding by collecting students' answers to the text-dependent questions, checking their work, providing written feedback, and maybe grading the assignment. Or, teachers can have students share out their responses and the teacher can provide verbal corrective feedback, allowing students to make corrections to their work during the discussion.

  2. Teachers can use the sample answer key at the end of the text-dependent questions to help them assess students' answers.

  Common errors/misconceptions to anticipate and how to respond: Please see the text-dependent questions sample answer key.  Also see Guided Practice above.

   

• Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?

  
  

  For literacy:

  1.  Before students complete the writing assignment, review the responses to the text-dependent questions. Make sure the misconceptions are corrected and the key points (as found in the sample answer key) are discussed.

  2.  After students' written responses have been graded and returned with feedback, teachers might wish to use the provided sample response with the class.  The teacher could show the sample response on an overhead or with an LCD projector and discuss some of the following:

  • How the topic is introduced with a "hook, as asked for in the prompt.
  • Go over how this writer opened his or her piece of writing. Brainstorm with students other ways the writer could have opened the piece.
  • Point out the use of textual specifics throughout the response.
  • Point out the writer's use of transitions throughout.
  • Point out how each paragraph addresses a different part of the prompt. 
  • In the final paragraph, point out how the concluding sentences support the main point. Brainstorm with students additional ideas about how to wrap up the piece. 

  3.  Throughout the sample response, have students identify the effective use of domain-specific vocabulary, including stratosphere, balloon sondes, ultraviolet radiation, cataracts, chlorofluorocarbons, and others (see the Note-taking Guide vocabulary list). Have them identify the use of academic vocabulary such as suppress, potentially, depletion, and refrigerants.

  4.  As one final option, teachers might want students to use the rubric to provide a score for the sample written response and have them justify the score they gave, possibly providing revision suggestions for any categories they scored lower than a 4.

  For science:

  1.  Ask the students to fill out an "exit ticket" on the last day of the lesson answering the following:

  • Why is it important to study the status of the ozone hole?
  • What are the main causes of the ozone hole?
  • One science concept I still have questions about is....

  2.  Use the information to address any misconceptions or gaps in knowledge the following day.

   

• Summative Assessment

  
  
  1. Students will individually respond to the writing prompt. They should be directed to respond with a multi-paragraph response, with a clear introduction, body section, and conclusion. They can refer back to the text as they construct their response.
  2. Provide students with a copy of the rubric and go over it with them so they will know how their written response will be assessed.
  3. Go over the writing prompt with students and make sure students understand what the prompt is asking them to address. Encourage students to underline key parts of the prompt as the teacher goes over it so they will remember to answer all the required parts.
  4. Teachers will use the rubric to assess students' written responses.

  Prompt: Using details and evidence from the article, describe how and why the ozone layer is constantly changing and why it was unusually large in 2015.  What is being done to prevent further damage? To grab your readers' interest, begin with a "hook" explaining how important the ozone layer is to humans’ survival on earth.

   

• Formative Assessment

  
  

  Specific suggestions for conducting Formative Assessment can be found in the Guided Practice and Independent Practice phases of the lesson where it says, "How will you check for student understanding?"

   

• Feedback to Students

  
  

  Specific suggestions for conducting Feedback to Students can be found in the Guided Practice and Independent Practice phases of the lesson where it says, "How will you check for student understanding?"