Summer Research Program for Science Teachers
Gregory D. Fisher
New Milford High School
CHEMICAL COMPOSITION OF EVERYDAY OBJECTS
Making chemistry relevant - especially to high school students at an introductory level - is important for effective student learning. This lesson addresses the challenge of relating a student's experience with an everyday object to chemical principles. To increase student interest, the format of this lesson - past the initial research - is for the student to continually update and revise the learned information on his/her own Webpage. [Teaching Standard A- Select and adapt curriculum to meet student interests]
An example that the properties of an object are based on its chemical composition is the ability of graphite (in pencil lead) to be easily transferred to paper, where it remains in a clearly defined shape. This property comes directly from the crystalline structure of carbon atoms in sheets. The carbon atoms within the sheets are held in place by covalent bonds. The sheets, however, are arranged in stacks that are held together by relatively weak van der Waals forces. When graphite is transferred from the pencil to the paper, it is these weaker bonds that are broken between sheets, and reformed between the carbon sheets and the paper. [9-12 Content Standard B- Structure and properties of matter]
Like graphite, diamonds are composed almost entirely of carbon atoms. However, the hardness of diamonds results from the crystalline structure where every carbon atom is bonded to five other carbon atoms using only the strong covalent bond. This comparison illustrates the different macroscopic properties of two objects that arise from the submicroscopic chemistry.
LESSON PLAN COMPONENTS
ˇ selecting an everyday object to investigate (student and instructor)
ˇ investigating chemical and physical properties of the object (student)
ˇ developing Webpage (student and instructor)
ˇ uploading and maintaining Webpage (student, instructor, and Webmaster)
SELECTING AN OBJECT [Teaching Standard B- Focus and support inquiries while interacting with students]
With the direct guidance and final approval of the instructor, the student will select an everyday object to investigate. Criteria for selecting this object will include, but not be limited to, the following:
ˇ student familiarity with the object (an ability to describe its macroscopic properties)
ˇ the object has clearly identifiable chemical composition with only one 'active ingredient'
ˇ information about the object's chemical and physical properties are easily available to the student (e.g., Merck Index or MS Encarta).
Obviously, the teacher should assist the student in selecting an appropriate (e.g., legal) object.
The initial information to be obtained by the student, in the early part of the course, is as follows:
B) Where Found:
D) Origin of Name: [9-12 Content Standard G- Historical perspectives]
2. Chemical Composition
A) Molecular Structure
B) For each atom, its: [9-12 Content Standard B- Structure of atoms]
v) Number of protons, electrons, and neutrons in the most abundant isotope
C) Other (e.g., ductile, malleable)
A) Why did you pick this object?
B) What might be of special interest to the reader?
DEVELOPING THE WEBPAGE
Each student, with the guidance of the instructor, will prepare a Webpage with the above information. The student will fill information that s/he has learned in a Webpage template created and supplied by the instructor. This will provide a consistent format for all of the student Webpages. Cooperative learning may be employed at this point, with the more computer-literate students helping those less computer-comfortable. [Teaching Standard E- Nurture collaboration among students] The student will return the Webpages (e.g., on 3˝" floppy disks), with the new information, to the instructor. The instructor, in turn, will compile all Webpages. The Webmaster will then upload the Webpages to the school's Website.
UPLOADING AND MAINTENANCE OF WEBPAGE
Working together, the instructor and Webmaster are responsible for uploading the Webpages so that they adhere to the design of the school's Website. As the course progresses, students are encouraged to add new information to their Webpage - for example, links to other internet sites, occupied orbitals of the individual atoms, and types of bonds in the molecule. [Teaching Standard D- Structure time for extended investigations]
A printout of the Webpage example for graphite (hyperlink: i'graphite.html) is linked here and immediately below here is the HTML source code. To view the HTML source code, cut and paste it into an appropriate program (e.g., MS WordŽ) and view with a browser (e.g., NetscapeŽ 3.01 or higher works best).
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