Sarah Nehring

EDTEP 587

3/14/03

Gas Laws:

Gases as particles in motion

High School Chemistry

10th and 11th grade

Subject Area Description:

This unit is designed for a high school Chemistry course, where the students are mainly 10th and 11th graders. It is designed for a school on a block schedule: classes meet every day for 90 minutes, and classes that normally would last one year last only one semester. The entire Chemistry class extends over two 9-week grading periods (quarters). Six units are covered in the second quarter, each lasting 1-2 weeks. The topics will be covered in this order: 1) chemical reactions, 2) calculations involving equations, 3) states of matter/ thermochemistry, 4) gases, 5) reaction rates and equilibrium, and 6) acids & bases. The students will have already addressed these topics during the first quarter: composition of the atom, electrons in atoms, the periodic table, bonding, and the mole. The unit I will be focusing on is “gases”. This unit will last 8-10 days, and will build upon the concepts addressed in the preceding “states of matter” unit. The major ideas addressed in this unit will be: the gas laws (PV=nRT, etc.), partial pressures, phenomena caused by the motion of gas molecules, and the kinetic molecular theory of gases.

The students in my classes appear to be from middle-class suburban families. I have heard this school described as “the most diverse in the Bellevue school district”, but from what I’ve seen the Chemistry classes are not that diverse. The students in my classes are about 80% white and 20% Asian or Indian. There do not appear to be any ESL students in my classes, and there are a few students with IEPs in each class. Most of the IEPs are students with learning disabilities in a specific area such as writing. Almost all of the students have taken at least one year of science at the high school before taking Chemistry, with the exception of two freshmen. Most students have taken Biology, some have taken Integrated Science as well as Biology, some of them have just taken Integrated Science.

Essential Questions:

My first essential question is: “how does the motion of gas particles explain the behavior of gases?” This question really gets at the meat of the whole unit. In order for students to explain the properties of a gas, such as pressure or temperature, on a molecular level, they have to explain it in terms of motion of gas particles. Answering this E.Q. will require understanding of the kinetic molecular theory of gases. Thoroughly answering this question will also require understanding the relationship between the properties, and why this is due to the motion of gas particles.

My second essential question is “Where do we find gas?” To answer this question, students will need to understand that just because something is invisible does not mean its not there. Students will understand that there is gas all around us, that we can feel gas all the time, and that it is vital for life in many ways. Students will need to know about gases in the body, in the atmosphere, in the water.

Learning Goals and Objectives:

  1. Student will develop abilities necessary to do scientific inquiry (EALR 2.1)
  2. Student will generate questions that can be answered through scientific inquiry
  3. Student will analyze questions that guide scientific investigations
  4. student will be able to design and conduct a scientific investigation
  5. student will formulate scientific explanations and models based upon logic and evidence
  6. student will revise his/her model based upon appropriate data and evidence
  7. student will be able to correlate models of the behavior of objects to the behavior of actual things (ex: gas behavior with the kinetic molecular theory)
  1. Student will effectively communicate scientific findings (EALR 2.1)
  2. Students will be able to present findings in a written lab report format, including a description of the guiding question, procedures, and conclusions
  3. Students will be able to present findings using graphical means, such as a graph, a chart, a flow chart, diagram, or a concept map.
  4. Student will be able to clearly explain orally his/her experiment, findings, and conclusion
  5. Student will be able to answer pertinent questions and defend his/her findings using evidence, logic, and background research.
  1. Students will understand the evolution of scientific ideas (EALR 3.1)
  2. student will be able to explain how we arrived at the ideal gas laws, in terms of historical scientists and experiments
  3. Student will understand that science involves testing, revising, and discarding theories based on available evidence
  4. Students will be able to explain how scientific investigations lead to theories, but not absolute truth
  1. Student will understand the properties of gases and the ideal gas law
  2. student will be able to explain how volume, temperature, pressure, and amount of a gas are related (gas laws)
  3. Student will be able to explain the kinetic molecular theory of gas
  4. Student will be able to explain these phenomena in terms of motion of gas particles and kinetic energy: temperature, pressure, diffusion, size effects
  5. student will understand that the total pressure of a mixed gas is equal to the sum of the partial pressures of its component gases
  1. Student will value chemistry as relevant and as applicable to real-life problems.
  2. Students will be able to give examples of how the gas laws affect their everyday lives
  3. Students will appreciate the impact some gases can have on the atmosphere

DAY 1

1. What will students do? / Demo: heat pop can with small amount of water, turn upside down into cold water. What does this have to do with gas?
Part I: Students will brainstorm ideas about gases, as a whole class.
Part II: In small groups, develop an initial model for the behavior of gases (give them some questions: what do gas particles look like? How do they compare to solids and liquids? What would happen if you squeezed a gas?). Students will be placed into “inquiry teams” for this unit, they will do inquiry experiments together and develop a model together. (Inquiry phase 1: start with students prior knowledge, develop a preliminary model, brainstorm)
Part III: Students will brainstorm questions they have about gases, compile a class list, hang it in classroom for duration of unit. Analyze the questions, label which ones are scientifically testable. Small groups discuss how to turn some of the questions in testable ones (Inquiry Phase 2- crafting questions)
2. Learning objectives for the class? / 1.1 & 1.2: students will develop and analyze inquiry questions
5.1: Students will be able to connect gases to their everyday lives and experiences
3. (a) Why introduce the idea at this time? / It is great to get all of their ideas and preconceptions out in the open before beginning a unit on a new topic
(b) Why use this instructional strategy? / Eliciting student ideas is appropriate to do at the beginning of a unit, so that I can discover what prior knowledge they have and what concrete examples would be useful to build on. I also think it is good to do one or two demos at the beginning of a unit because chemistry students like to see things blow up and it will spark their interest!
4. What evidence of student learning/understanding will I collect? / Small groups will make a poster of their initial model. I will be able to see the brainstorm list of ideas and questions
5. Required Resources? / Giant posterboard papers for groups/ the post-it kind so they can stick their models up on the wall. Pens.

DAY 2

1. What will students do? / Part I:
What elements are gases? 10 groups of 3, get to pick a gas to make a poster listing its properties, using Merck index. This will be a short activity, hang these posters up on the wall
Part II:
Lecture: introduce kinetic molecular theory. What are the main tenets of this theory?
Part III: (2 days)
Guided Inquiry: determine the mathematical relationship between pressure and volume of a gas? Develop a good hypothesis with your group before beginning lab (inquiry phase 2: hypotheses). Students are given materials and given a question, and they need to design and conduct their own experiment. (inquiry phase 3)
After conducting the experiment, students will need to analyze their data, and turn it into a mathematical model for the relationship between pressure and volume. (inquiry phase 4: analyzing data and using it as evidence)
Students will be required to turn in a formal lab report from this experiment.
2. Learning objectives for the class? / Students will have a sense of where we find gases (Essential Question)
Students will develop skills necessary to do scientific inquiry
Students will discover the relationship between pressure and volume
Students will be able to explain the kinetic molecular theory of gas
3. (a) Why introduce the idea at this time? / I’d like to let the kids dive right into an experiment before I teach them very much in this unit. It will give them experiences in which they can ground their learning for the rest of the unit. (inquiry phases 3 & 4: design the investigation, and analyze data and representing it as evidence)
(b) Why use this instructional strategy? / Doing inquiry rather than lecture will make the concept concrete. Spending the time trying to figure out the theory will cement the idea into their head and will increase retention. Students will value the theory more and see its relevance if they experience it hands-on
4. What evidence of student learning/understanding will I collect? / Gas posters: could they complete the assignment accurately?
5. Required Resources? / Gas posters: poster paper, pens
Inquiry lab: for each group: syringe, four bricks, support block.

DAY 3

1. What will students do? / Part I: lab
Continue inquiry lab from yesterday
Part II: revise model
Modify their model of gas behavior, based upon inquiry experiment. Present modified model to class, informally (inquiry phase 5)
2. Learning objectives for the class? / Students will develop skills necessary to do scientific inquiry
Students will discover the relationship between pressure and volume
Students will revise models based upon evidence
3. (a) Why introduce the idea at this time? / See yesterday
(b) Why use this instructional strategy? / See yesterday
4. What evidence of student learning/understanding will I collect? / Formal lab report from inquiry lab.
Presentations of revised model of behavior of gases.
5. Required Resources? / See yesterday

DAY 4

1. What will students do? / Part I: Lecture. Recap yesterday’s inquiry and label this relationship between P & V as “Boyle’s Law”
Part II: Pressure.
Pressure = Force/Area. Brainstorm the idea of “force”
Demonstration: molecular motion machine. On overhead, a machine that pushes marbles around to mimic random motion of gas particles. Change size of box to see why change in volume affects change in pressure.
Demonstration: have students act as gas particles. Stop them at certain places so they can observe the force exerted on a wall.
Part III Temperature:
Using same examples, talk about speed and motion, temperature is the measure of the average kinetic energy of the gas particles
Part IV: Volume and Temperature.
Have students hypothesize what they think relationship will be, come up with a model explaining this (go back to original model, change and expand it). Present models to the class
Demo: balloons, fill with same amount of gas, put them at different temperatures, notice the change in volume.
2. Learning objectives for the class? / Students will discover the relationship between pressure and volume
Student will be able to explain pressure and temperature in terms of molecular motion
3. (a) Why introduce the idea at this time? / Now that they have observed pressure, we’re going to explain what it is on a molecular level.
(b) Why use this instructional strategy? / Time constraints, I can’t have them do everything by inquiry, I need to do some direct instruction. I think that the molecular motion machine will help students visualize the motion of the particles, making the concept less abstract
4. What evidence of student learning/understanding will I collect? / Present revised models to class.
Informal assessment: do they seem to be following along with the lecture?
5. Required Resources? / Balloons, freezer, hot bath or incubator

DAY 5

1. What will students do? / Part I: Guided Inquiry
Is there a mathematical relationship between the pressure and volume of a gas?
Have students do lab write-up as homework.
Part II: revise model. Give students a chance at the end of class to revise their model.
2. Learning objectives for the class? / Students will explain the mathematical relationship between pressure and volume of a gas.
Students will develop skills necessary to do scientific inquiry
Students will revise model based upon evidence
3. (a) Why introduce the idea at this time? / I would like to introduce all of the two variable relationships before learning about the ideal/combined gas law
(b) Why use this instructional strategy? / This is a great activity that helps the students really visualize this relationship. They will have to formulate the math using their own data, which will help in retention and comprehension
4. What evidence of student learning/understanding will I collect? / Lab write up
Presentation of Model
5. Required Resources? / Lab: syringes, beakers, water, ice, hot plates, thermometer

DAY 6

1. What will students do? / Part I: Recap yesterday’s experiment, talk about the relationship between pressure and volume.
Reading: “gas laws and scuba diving”
Part II: Lecture: Talk about the fourth relationship: amount of gas related to volume and pressure.
Put together all four variables into the ideal gas law!
Students will do practice problems applying the ideal gas law.
2. Learning objectives for the class? / Students will explain the mathematical relationship between pressure and volume of a gas.
Student will be able to explain the mathematical relationship between amount of gas to the pressure and volume.
Student will be able to describe real life application of the gas laws
Student will be able to describe the ideal gas law and use it to solve problems.
3. (a) Why introduce the idea at this time? / I want to introduce the ideal/combined gas law after discussing each of the variables individually. At this point, each variable should make sense to the student and this “ideal gas law” will seem somewhat logical
(b) Why use this instructional strategy? / Direct instruction seems effective because of 1) time constraints, 2) I haven’t heard of a good lab you can do to get students to develop the ideal gas law on their own
4. What evidence of student learning/understanding will I collect? / Practice problems
Students answers to questions during lecture (informal)
5. Required Resources? / None

DAY 7

1. What will students do? / Part I: Day to catch up with other things haven’t finished…
Part II: Historical Readings
Reading: “Toricelli on the Weight of the Atmosphere.” Read in team groups. Make a list of the questions the scientist had, and the inquiry steps he took. Reflect in journal about how his experiments and thought processes are different from yours. What evidence is available now that was not available to him?
2. Learning objectives for the class? / Students will understand the evolution of scientific ideas.
Students will understand that science involves testing, revising, and discarding theories based upon available evidence
3. (a) Why introduce the idea at this time? / This seemed like a good break point, take a break from doing labs and try something different
(b) Why use this instructional strategy? / I found a really good reading on this that I think will be interesting to the students!
4. What evidence of student learning/understanding will I collect? / Journal entry
5. Required Resources? / Reading: “Toricelli on the Weight of the Atmosphere.”

DAY 8

1. What will students do? / Part I: Weather
Reading: Cooperative groups will jigsaw readings on weather and weather balloons
Part II: mini-project
One day project: design a weather balloon that will measure the weather at the top of Mt Everest (29,000 ft high). Tell me what gas you will use, how much (n), and what size (V). Justify your choices while mentioning pressure and temperature.
2. Learning objectives for the class?
3. (a) Why introduce the idea at this time?
(b) Why use this instructional strategy? / Jigsaw will encourage cooperative work. It will also allow students to get at a large body of information without having to do a ton of individual reading
The mini-project will allow them to apply some of the knowledge they have learned, allowing them to see the application of the gas laws, and hopefully making them more entertaining and fun.
4. What evidence of student learning/understanding will I collect? / Report on mini-project, weather balloon.
Listen to group work, see if people understood the reading
5. Required Resources? / Readings on weather and weather balloons: “Five guiding principles of meteorology”, some various readings from the web entitles “weather balloons”

DAY 9