Lesson Plan Template: Confirmatory or Structured Inquiry
Learning Objectives: What will students know and be able to do as a result of this lesson?
Students will be able to explain what determines the density of a substance. Students will be able to predict the behavior of a gas relative to air using density.
Students will be able to explain how a substance can change state and discuss what factors affect state change.
Students will be able to predict the conditions under which gases can be dissolved in water.
Students will be able to explain, using the kinetic molecular theory, why gases expand or contract with varying temperature and pressure. Students will predict the behavior of gases under varying conditions of temperature and pressure.
Students will be able to discuss the relative density (high or low), relative boiling point (high or low) and relative intermolecular forces (high or low) of a given substance based on its boiling point and other witnessed gas behavior.
Students will be able to explain gas pressure in terms of the kinetic theory, and relate temperature and average kinetic energy of particles of a gas.
Students should be able to recognize that the factors increasing the solubility of solids actually decrease the solubility of gases (inverse relationship between solubility of gases vs solubility of solids).
Prior Knowledge: What prior knowledge should students have for this lesson?
Students should be familiar with the factors that affect the physical state of a substance.
Students should know the characteristics that distinguish gases, liquids and solids.
Students should be able to explain density.
Students should know that some things dissolve in water and others do not. Students should be able to briefly discuss what factors affect the solubility of solids (think of how you would dissolve sugar easily in water).
Students should recognize that gases are compressible.
Students should know that particles of matter are in constant random motion.
Students need to be familiar with particle motion being influenced by temperature or pressure.
Students should know that gases travel from areas of high pressure to areas of low pressure.
This prior knowledge will be assessed through preliminary questions as well as through open discussion of the material.
Guiding Questions: What are the guiding questions for this lesson?
Why does an air balloon rise? Ans: Warmer air is less dense than cooler air. Less dense air in the balloon will cause it to rise.
Why do you have to boil pasta for a longer duration at high altitudes? Ans: Less air pressure pushing down on the water makes it easier to boil. However, the boiling water is now at a lower than normal temperature, so the pasta requires a longer cook time to offset the lower boiling temperature.
Why does an inflated balloon shrink in the freezer? Ans: The cooler temperature slows gas particle movement. With less movement, there are fewer particle collisions, thus lowering the pressure inside the balloon relative to the outside air pressure. Subsequently, the balloon shrinks. The opposite is true if the balloon were put in boiling water.
Why is propane, normally a gas at room temperature, a liquid (as evidenced when you shake the canister) inside your grill's tank? Ans: The propane is under extreme pressure. The particles are much closer together, thereby increasing attractive forces between particles. The chain of these events causes the gas to condense into a liquid.
Introduction: How will the teacher introduce the lesson to the students?
Script: "Every time you burp, you release carbon dioxide. Imagine if one burp released enough carbon dioxide to suffocate an entire town. Is this possible? The tragedy at Lake Nyos suggests, 'yes'."
To demonstrate the differences in gas behavior, the teacher can place dry ice on the lab table. Students should notice immediately that the solid becomes a gas. Students should be able to infer that carbon dioxide has a very low boiling point (as evidenced by how cold it must be to be a solid AND how easily it becomes a gas at room temperature. Students should witness how dense carbon dioxide is based on how it flows downward off the lab bench. Finally, if the teacher places a piece of dry ice in a beaker of water, the students will be able to witness first hand the "burping" that Lake Nyos underwent.
Nyos provides a memorable introduction to the concept that water contains dissolved gases, and under certain conditions, those gases can escape.
Investigate: What question(s) will students be investigating? What process will students follow to collect information that can be used to answer the question(s)?
How do gases behave (solubility, diffusion, density, volume, etc.) under different conditions?
The students will follow a structured inquiry activity to recognize that density, intermolecular forces, pressure and temperature all affect how a gas behaves.
Analyze: How will students organize and interpret the data collected during the investigation?
Through class discussion, the students will be able to explain the mechanisms governing the behavior of everyday gases (weather balloon, carbonated beverages, aerosol products, etc.).
Through the reading exercise and lab activity, the students will be able to explain the factors affecting gas behavior in the everyday environment.
Closure: What will the teacher do to bring the lesson to a close? How will the students make sense of the investigation?
As a summary explanation of the events that unfolded at Lake Nyos in 1986, the class will watch a brief video (3.5 min) of the tragedy at Lake Nyos. The teacher will then proceed to give the "exit" quiz; upon completion, the answers to the quiz will be reviewed to ensure understanding.
Each group will be responsible for handing in a "lab report" with a record of their findings and answers to the questions. A short quiz involving free response and multiple choice questions will be administered to assess the individual's understanding of the material.
After engaging the students with a brief video of the tragedy at Lake Nyos, the students will divide themselves into five groups of five. Their task is to answer one question from the formative list of topics given by the teacher. The topics will be assigned randomly by the teacher. To aid with the discussion, a list of factual information relevant to the topic will be provided. Each group will then discuss the topic among themselves, answer the posed question using prior knowledge and the facts provided, and finally present their findings to the class. In this fashion, the teacher can asses each group's general strengths and weaknesses regarding the topic of gases and their properties. In addition, each group will strengthen their understanding by listening to the other presentations.
Feedback to Students
Immediate feedback will be given by the teacher to each group after their presentations to the class. Following presentations, each student will individually read a literary piece on the tragedy at Lake Nyos. A list of key concepts will be listed on the board to help guide the students in their reading. The goal during reading is for each student to be able to cite five key facts regarding the cause and effect of the disaster.
The teacher will ask pointed questions regarding the key concepts from the reading. For each question by the teacher, students will hold up a white board with their answer above their heads (while looking straight ahead). In this fashion, the teacher can appreciate the scope to which students know the necessary background information for the day's activity, and students will NOT be able to see each other's answers.
The day's lab activity will be closely observed and monitored by the teacher. Members of the same group will cooperate to record all necessary information, as well as answer all follow-up questions regarding the lab activity. During this time, all students will have a chance to confirm with the teacher their findings and answers to the lab questions.