Inquiry module using technology

The junior level high school chemistry course is by nature based on a certain level of constructivism in terms of the material building on itself. I remind students daily of how important each and every lesson is, as we build upon previous knowledge. Scaffolding is a term I like to use when I describe to students how they are storing this information. When they begin to start making connections between previous information and only then can they move on to understand chemistry in more detail. The learning cycle lends itself to the learning of chemistry. I feel naturally we run a cycle as we build throughout the year to the point at the end, when we conduct analytical chemistry in the lab and turn out our most complicated stoichiometry and gas law problems. With the internal and external pressure on a high school chemistry program it can be challenging to get away from traditional “drill and kill” method that many chemistry teachers have had “success” with. With the rigors of freshman chemistry classes at the college level the responsibility is high. Weak chemistry preparation has caused some future scientists to fail freshman chemistry at the college level and end up as PE teachers and basketball coaches among other lesser professions. The National standards are in place to support the use of inquiry. Furthermore the use of inquiry can, I believe, be used very effectively to not only engage students and have them enjoying a course that many dread before they walk in the door, and effectively cover the content that needs to be covered a high school level course. Chemistry is a process of building a set of steps to walk on to get to the top and understand the content based on understanding of previous lessons. When students begin chemistry we start with the basics such as factor label method, scientific notation, and metric units. If students have struggled with fractions in the past, they need to relearn the steps to stand on before they can begin climbing the chemistry steps they must build. The same is true for scientific notation. I feel that a constructivist approach with the use of experiments and experiences is definitely the best way to prepare my chemistry students.

This activity is designed to cover the following learning goals from Junior Chemistry at Libby High School:
Understand the nature of binary ionic bonds
Characteristics of binary ionic compounds
Behavior of binary ionic compounds in solution

*Note: to appreciate this lesson you need to have Internet access and have a firefox window open already there are hyperlinks throughout*

Engage:
Modified from the 4.15 Heat water above it's boiling point from Liem’s book, thanks Quinn.

This setup is similar to the one I use. Instead I use a hot plate and a 250 ml beaker
The thermometer is a Vernier temperature probe, which is hooked into a computer that is hooked into a projector and projected on the screen at the front of the room so the students can see the real time temperature data being plotted on a scatter plot. We heat the water 150-200 ml from room temperature to boiling. Distilled water is optimal. When the water begins to boil add some salt. NaCl is cheap and works fine. The temperature drops as result of the cooler salt being added to the solution. Then observe as the temperature goes back up until the solution boils again only this time at a higher temperature. Interesting… Have students make detailed observations in their science notebook. Have them write questions, testable and researchable. Have them get into small groups and discuss what they think might have happened and encourage them to answer each others questions to the best of their ability.


Explore:
Now we begin to explore the content a bit with some easy-on-the-eyes technology called youtube. Youtube is one of the best resources available to high school science teachers and is often blocked by school districts. Shown again on my main projector at the front of the room this is a very cool animation with no words showing a 3d Bohr model of a sodium and a chloride atom and what happens to one sodium electron as the two enter an ionic bond. There are no words or sound in this animation so the students have to build their own narrative of what is happening. In their science journal they have to describe what is happening the best that they can, as well as formulate at least one question perhaps two or three. They are allowed to rewind, pause, slow motion, however they would like to view it while formulating their questions and making their observations. Students are then allowed to get into their learning groups and discuss what they wrote and make comments or adjustments in their journals after discussion in groups. Several of their questions and comments are shared with entire class. Then we watch the next short youtube clip. The first clip is around 30 seconds, while the second one is 20 seconds, so these are not terribly time consuming so the focus is not on the technology but instead on the content. This one describes what was shown on the last clip only this time with some commentary. Students are again allowed to get into their learning groups and discuss what they wrote and make comments or adjustments in their journals after discussion in groups. Several of their questions and comments are shared with entire class and key researchable questions are added to my white boards at the front of the room. What is a crystal lattice? We briefly discuss the crystal lattice with examples, and then view this animation of a crystal lattice. I then show them a few models of crystal lattices of various compounds constructed by former students. Then I show a great animation of salt dissolving . You have to go to the following website and simply follow the directions there. It is slightly more complicated than point and click, and you have to unzip files, but there is a list of simulations and animations that are great and free for use in the chemistry classroom. This one is called “Sodium chloride dissolving in water.” This is a Great 3 dimensional view at the atomic level that does a great job of letting students see exactly how Na+ and Cl- ions disassociate from one another in the cubic salt crystal and are attracted to the polar ends of the water molecules. There are several options to manipulate the simulation. Engage in student directed tinkering with the simulation, while the students write more down and begin to construct their own idea of how and why the water might have boiled at a higher temperature when salt was dissolved in it (discrepant event).


Explain:
After viewing the youtube videos and the animation of salt in water lead a discussion of understandings about ionic bonds, ionic compounds, and properties of ionic compounds. Guide students to construct nature of ionic bonds in terms of energy, electrons, and properties of ionic bonds. Compare and contrast ionic and covalent compounds, and finally brainstorm good characteristics of ionic compounds via testable questions. Have students narrow to a shorter list, maybe six to eight testable questions. Hopefully at some point we will be able to discuss some exceptions to the normal characteristics, such as Rubidium Silver Iodide, which does conduct electricity quite well. Because of the structure of the crystal lattice of RAg4I5, silver ions are allowed to move freely throughout the structure. Have them think about an experiment to quantify, or observe characteristics of ionic solids at various states, or suspended in solution. Again have them document testable questions that could be used for an experiment of their own design.


Extend:
Have them break into groups to design and perform an experiment f their own design. This experiment should be based on one of the testable questions articulated in the brainstorming session. I will narrow the focus to characteristics of binary ionic compounds. This is the point when preparation will be the toughest. Over several years I imagine having a much better idea what types of experiments the students will want to conduct. They need to record observations and explanations with at least one data table of their own design. They also need a conclusion that answers their initial research question (hypothesis). They will also be asked to use digital photography to as evidence and documentation for their labs, as the use of imagery is a valuable strategy as well.


Evaluate:
I have a new plan I have put together this summer for closure on various explorations throughout the year. I plan to have one wiki page set up where each cooperative learning group (lab group) has a login name and a password, which gives them access to the wiki page. A wiki page simply put is a web page that all members are able to create content, post comments, and make changes. Using our standard format for lab reports, that the students will be very familiar with at this point in the year, to post the lab reports on the lab wiki page. In the lab reports there should be at least one photo from the lab as well. The students will then be required to read three other reports from other groups, leaving suggestions for improvement, comments about what they liked, and other related appropriate comments. Most importantly there should be questions left by groups as they read other reports for further experimentation. The students should also give a score based on a rubric for their own and three other groups’ labs. I will also score each group based on the same rubric and the score they get will be based on a combination of self-assessment, classmates, and my grade. For further exploration I would have them log into computers themselves individually or in their groups and run a simulation on the computer, from the same website described earlier in the NaCl dissolving in water animation, that allows students to combine the elements (written only as symbols) H, Li, Na, K, Mg, Ca, C, N, o, F, P, S, Cl, Br, and I virtually. The program will show their shape based on electron density. They will over time be able to tell the Ionic compounds from the covalent compounds, which is another great starting point to start the cycle all over again, building on student’s previous knowledge. At some point near the conclusion of the activity I would have them draw a concept map in their science journal as closure to the activity to demonstrate understanding of ionic compounds.