If you have access to a Van de Graaff generator, go to this this site to learn how you can easily show students how a capacitor works. (http://www.lhup.edu/~dsimanek/scenario/e-stat.htm)
This video clip (8:53) shows the charging and discharging of a capacitor and explains the physics behind the charge-discharge cycle. (The physics may be more than you need in your classes.) (https://www.youtube.com/watch?v=OfL3QWJSCu0)
MAKEZINE.com provides a nice video (8:00) on capacitors (albeit a bit dated—uses a cassette tape recorder in a demonstration): https://www.youtube.com/watch?v=ZYH9dGl4gUE. The narrator shows what capacitors are and how to make one for yourself using very basic materials.
Here is another video (13:25) from CoolContraptionGuy that fully describes how a capacitor works. It includes a description of electron flow through the capacitor. He demonstrates a very simple way to make a capacitor at home (or in the lab). (https://www.youtube.com/watch?v=PAPGTuvHSRo) [Beware the analogy he uses with magnets representing the electrons: the cardboard between them allows magnetism through, but a dielectric (the insulation between the plates of a capacitor) doesn’t allow electricity to flow through.]
Some of the properties of Gorilla Glass can be explained in terms of the Prince Rupert drop. Flinn Scientific’s video (10:46) shows teachers how to make such a drop, how to test its strength, and then uses polarizing films to show internal stresses: https://www.youtube.com/watch?v=5zxZkK2aJig.
This video (6:39) from “Smarter Every Day” shows same thing, but larger and in slower motion, making the destruction more obvious: https://www.youtube.com/watch?v=xe-f4gokRBs. The narrator does a good job of explaining and visualizing internal stress in the drop.
If you want students to sharpen their periodic table skills, you might take them to the Merck Web site, http://pse.merck.de/merck.php?lang=EN. There they can work with an interactive periodic table that gives them lots of facts about the elements, but they can also choose to play a quiz-style game online that tests their knowledge/understanding of the periodic table. Some of the questions are fact-based, and some are based on trends in properties of the elements. Several more games for students (“Mendeleev Activity”, “Identify the Element”, and “Find the Element”) can be found at the Royal Society of Chemistry (RSC) Periodic Table of Data Web site at http://www.rsc.org/education/teachers/learnnet/ptdata/games/identifyelement.htm. Any of these “games” could be used as part of your lesson on, or a review of, the periodic table.
These sites provide lessons on graphing data about the elements in order to develop the concept of periodicity and the periodic table:
These use TI Graphing Calculators: http://science-class.net/archive/science-class/Lessons/Chemistry/Periodic%20Table/Graphing%20Periodic%20Properties.pdf and http://go.hrw.com/resources/go_sc/ssp/HK1CBL103.PDF
This one uses graph paper: http://www.evanschemistrycorner.com/Labs/Periodic_Table/L3-3A_Graphing_Periodic_Relationships.pdf.
This one uses a spreadsheet for graphing: http://science-class.net/archive/science-class/Lessons/Chemistry/Periodic%20Table/Graphing%20Periodic%20Properties.pdf.
And this one is a lab activity that uses actual samples of elements for students to use to determine densities via weighing and obtaining volumes by water displacement. Then they graph their data and compare the density of an unknown metal with their results to determine its identity. (http://dwb.unl.edu/calculators/pdf/PProperties.pdf)
Out-of-class Activities and Projects
(student research, class projects)
You can assign each student a different metal used in the smartphone and ask them to research and find out the chemical nature of the metal’s ores, where geographically the ores are found, and how the ores are refined into metal. You may choose to ask your students to pay special attention to any issues of geopolitics or economics that relate to their assigned metal. (For example, you may ask the student assigned aluminum to consider why Jamaica is such a poor country despite producing most of the world’s bauxite aluminum ore.) You may ask your students to present their findings as a written paper, a class presentation, a poster, or in some other medium.
You could assign each student a different metal used in the smartphone and ask them to research and find out the specific uses/roles that metal plays in the performance of the smartphone.
Students could research the properties of specific metals that make them useful for specific purposes (such as the smartphone) and then research the possible substitutes for those same specific metals, and report on the shortcomings of the substitute.
30 Years of ChemMatters Available Now!
The references below can be found on the ChemMatters 30-year DVD (which includes all articles published during the years 1983 through April 2013 and all available Teacher’s Guides, beginning February 1990). The DVD is available from the American Chemical Society for $42 (or $135 for a site/school license) at this site: http://ww.acs.org/chemmatters. Scroll about half way down the page and click on the ChemMatters DVD image at the right of the screen to order or to get more information. Selected articles and the complete set of Teacher’s Guides for all issues from the past three years are available free online on the same Web site, above. Simply access the link and click on the “Past Issues” button directly below the “M” in the ChemMatters logo at the top of the Web page.
Baxter, R. Glass: An Amorphous Solid. ChemMatters1998, 16 (3), pp 10–11. The author discusses the composition and structure of glass.
Fruen, L. Liquid Crystal Displays. ChemMatters2005, 23 (3), pp 6–9. The article discusses liquid crystal displays and how they work. The author discusses recent improvements in the technology behind LCDs. Cell phones are mentioned as using these displays, but smartphones weren’t yet available.
The ChemMatters Teacher’s Guide for the October 2006 issue has an extensive background information section on glass. The guide accompanies the article, “Glass: More than Meets the Eye”, which deals with glass involved in forensics. (Rohrig, B. Glass: More than Meets the Eye. ChemMatters2006, 24 (3), pp 4–7)
Michalovic, M. Tantalum, Congo, and Your Cell Phone. ChemMatters2007, 25 (3), pp 16–18. Author Michalovic shows how cell phones are linked to conflict in the Congo. He provides a story “where chemistry, physics, and world events all meet.” The article also describes in some detail how capacitors work in cell phones. (Note: this article precedes “smartphones”.)
The October 2007 ChemMatters Teacher’s Guide that accompanies the Michalovic cell phone article above provides background information on capacitors, as well as several activities and videos students or the teacher can do or view in the classroom.
Becker, R. Question from the Classroom, Part II. ChemMatters2008, 26 (2), pp 2–3. In this article, Becker answers a student’s question about the difference between soda lime glass and Pyrex, or borosilicate, glass, and why soda lime glass (as in a test tube) shatters when it is heated hard. He includes several diagrams to show the difference between a crystalline substance and a glass at the molecular level.
Pages, P. Did You Know? … Rare Earth Metals: Not Well-Known but Critical for High Technology. ChemMatters2010,28 (2), p 2. This ½-page article briefly discusses what rare earth metals are, where they can be found, and what they’re used for.
Karabin, S. It’s All about Liquid Crystals. ChemMatters2010,28 (3), pp 14–16. This article discusses liquid crystals and liquid crystal displays (LCDs) in great detail. It explains what liquid crystals are, the three types of liquid crystals, and how polarizing filters are used to make the crystals visible on the display screen. It shows a smartphone using LCDs.
Sitzman, B.; Goode, R. Open for Discussion: Could Cell Phone Radiation Damage our Brains? ChemMatters2010,28 (4), p 2. This one-page article describes the controversy regarding potential harmful effects of radiation emanating from cell phones. It focuses on the electromagnetic spectrum.
Rohrig, B. Myths: Chemistry Tells the Truth ChemMatters2010,28 (4), pp 8–10. One of the myths “busted” in this article is about ancient window glass that is thicker at the bottom, and the belief that this is due to glass being a liquid that flows over eons of time. In the “busting”, the author explains the structure of glass, and how window glass was made in days of old.
Sitzman, B.; Goode, R. Open for Discussion: Lithium-Ion Batteries: A Clean Source of Energy? ChemMatters2011,29 (3), p 2. This one-page article describes the chemistry of lithium-ion batteries, as well as the concerns over the source (foreign), and environmental issues involved with the extraction of the raw material lithium and the production of the batteries.
Tinnesand, M. Graphene: The Next Wonder Material? ChemMatters2012,30 (3),
pp 6–9. This article discusses idea of a flexible smartphone, based on a display screen made of graphene (a one-atom-thick layer of carbon). The focus of the article is actually on nanomaterials. Two other items described in detail are bionic devices made of graphene, and flexible solar panels, also made of graphene.
The article “Glass Doesn’t Flow and Doesn’t Crystallize and It Isn’t a Liquid” provides additional details on scientific study of the glass flowing myth.
(Hawkes, S. J. J. Chem. Educ. 2000, 77 (7), pp 846–848; full text available for subscribers at http://pubs.acs.org/doi/abs/10.1021/ed077p846)