In the Classroom
Periodic Table Target: A Game That Introduces the Biological Significance of Chemical Element Periodicity Richard S. Sevcik, Ragan L. McGinty, and Linda D. Schultz* Department of Chemistry, Geosciences, and Environmental Science, Tarleton State University, Stephenville, TX 76402; *
[email protected] Susan V. Alexander Comanche High School, Comanche, TX 76442
In general, schools focus on the visible physical and chemical properties of matter in the lower grades (3–7) while the basic, but unseen, building blocks of matter—elements and their arrangement on the periodic table—are not explored until eighth grade or high school. Students often memorize facts about periodic table element arrangement without understanding the significance of the elements themselves. The activity described here helps students appreciate the role of each element in the make up of the world, allows them to see the periodic table groupings as related to life on Earth, and reinforces the concept of using different classification schemes for different purposes. Traditionally the elements are presented as families (e.g., alkali metals, halogens, etc.) so that similar physical and chemical properties and periodic trends may be explored. This game emphasizes the effect or utility of each element on living organisms, and thus may help students appreciate connections between chemistry and daily life. Biological classifications used for the game include: essential elements; essential ions; essential trace elements; noble gases; toxic elements; radioactive elements; and those with no major effects (1). Depending upon time and class level, additional discussions could include LD501 and TLV2 levels (2), or the presence and uses of radioactive isotopes of essential elements. Incorporating these topics increases students’ interest and engages them in the lesson (1, 3). Supplies, Materials, and Preparation Supplies needed for this activity include (4):
• Rigid backboard for the periodic table target
• Felt cloth of at least seven different colors
• Color markers
• Fabric scissors
• Fabric glue and hook-and-loop strips
• 8 ping-pong (table tennis) balls
Students can select or be assigned the elements to classify, then research them for homework or in the school computer lab and share their findings with the rest of the class the next day (5). This gives the instructor a chance to check accuracy and allows all students to record information on all the elements. Thus, before the project is begun, the instructor should provide students with a handout listing the elements to be investigated with a blank beside each and a listing of the possible biological classifications to be used. (See the online supplement.) To enrich the activity, students could also be required to find an application (if one exists) for their elements and one “cool or fun” fact about each. It is important to emphasize that students need to research the biological aspects of an element 516
rather than the traditional classification because the elements will typically be referenced by family names on most Web sites and in books. Students will need to dig deeper and sometimes make inferences about the biological role of an element based on reading the text of an article rather than copying down the first classification they find in the literature. Preparing the Target Backboard A 23 × 17-in. corkboard can be purchased relatively inexpensively at an office supply store. It serves as a sturdy, lightweight backboard and has the added advantage of already having hangers attached. Measure and cut a piece of 36 × 30 in. white felt, place it over the front of the corkboard, and attach it to the corkboard from the back with staples or tacks. Draw an outline of the periodic table on the front of the felt-covered board using a black permanent marker and hang the board on the wall. See the online supplement for detailed instructions and a template. Placing the Elements on the Table Students report their research results concerning the biological importance of each element to the whole class (a key is included in the online supplement). If there is a major discrepancy between a student’s classification and the key, this should be addressed. This will probably require one class period; however, this will provide students with a better understanding of the topic. Students can also color-code paper periodic tables while the results are presented for their own further reference. When all elements have been classified, students cut pieces of appropriately colored felt for each element, use a black permanent marker to label each felt piece with the appropriate atomic number and symbol, and glue them in the correct position with fabric glue. To save a significant amount of time, the instructor can cut a number of pieces of felt to the correct size in advance so that the students only need to label and glue them. Because all elements with an atomic number of 84 and higher are radioactive, the instructor may wish to simply cut out a felt strip of the appropriate size and color, divide it into elemental spaces, label the spaces appropriately, and paste it into place without assigning these elements to the students. The lanthanides (atomic numbers 57–70) all have “no major biological effects”, except for Promethium (61), which is radioactive, and may be treated in the same manner. This saves time, and the educational point is still made. Student Participation Students are given three handouts, all of which are available in the online supplement. Handout 1 is a form on which the students record their data regarding specific aspects of the
Journal of Chemical Education • Vol. 85 No. 4 April 2008 • www.JCE.DivCHED.org • © Division of Chemical Education
In the Classroom
elements. Handout 2 describes the construction of the table and the rules of the game. Handout 3 is a scorecard students can use while playing the game. Playing Periodic Table Target Abbreviated instructions and game rules are summarized below. More complete directions are provided in the online supplement.
1. Your teacher will give you a blank element information chart with all the elements listed. Draw for the names of the specific elements you will research. As homework, or in the school computer lab, you will research the effect of your elements on living organisms.
2. Classify each of your assigned elements as follows: essential elements, essential ions, essential trace elements, noble gases, toxic, radioactive, or no major effects. You may also be required to find a use and a “fun fact” about your elements. On report day, share your findings with the class so that everyone has a complete listing.
3. Obtain a 3 × 4-cm block of felt of the appropriate color for each of your elements, label it with the symbol of the element using a black marker, and glue it onto the appropriate place on the blank periodic table provided. Felt colors and game point values are as follows: Green (essential elements) Blue (essential ions) Pink (essential trace elements) Yellow (noble gases) White (no major effects) Orange (radioactive elements) Purple (toxic elements)
= +4 = +3
= +2 = +1 =0 = ‒2 = ‒3
4. After the glue dries, play the game. Pick a partner. Obtain four of the same color of Velcro-covered ping pong balls. Decide who will go first. During your turn, stand behind a line taped on the floor about 6–8 feet from the board and toss the balls underhanded (or the Velcro will not stick). 5. Player one throws all four balls at the periodic table target with the goal of scoring 15 total points (to win), writes down the score and removes the balls. Player 2 repeats the procedure. If neither player has scored 15 points, the game repeats until one player reaches 15 points. If the first player reaches 15 points first, the second player is allowed to complete the round, and the player with the higher number of points is declared the winner. Tie scores may be settled by a coin toss or a “sudden-death” playoff where player one throws one ball, then removes it, and player two throws one ball and removes it until the tie is broken.
Although the instructions in the online supplement describe the game as similar to a dart game, several modifications are possible. For example, if it is not feasible to hang the board on a wall (if the game must be played in the center of a large room or outdoors for an event such as a carnival), the game may be placed flat on a table and the players can “lob” the ball at the target. The balls will stick, but it is much more difficult to control this type of throw. Another variation is to make a much larger table and simply draw it on a piece of poster board and have students color or paint the elements the appropriate color. This can be placed on the floor and players can toss objects that will slide, (e.g., coins), in a version of a carnival midway game.
Conclusions This game provides an enjoyable way for a class to work together as a group to learn about the biological activities of the chemical elements while simultaneously becoming more familiar with the form and structure of the periodic table. The project allows students to observe correlations between chemistry and biology and serves as a reference for later, more traditional study of periodic properties of the elements and their placement on the periodic table. Preparing for the game also reinforces the process skill of making inferences, because students must analyze the information they research about their element to find its biological significance. Once students notice the clustering of essential elements on the table, they may become more aware of the biological significance of the elements of life on Earth. Acknowledgments This game was originally developed by undergraduate students in response to the American Chemical Society’s 2005 National Chemistry Week Chemvention challenge to “develop a toy that teaches chemical principles for a total cost of less than $250” (4). The financial assistance of The Robert A. Welch Foundation, Chemistry Departmental Grant AS-0012 is gratefully acknowledged. The authors wish to thank O’Dell Hicks for his assistance in providing the graphics for the online supplement. Notes 1. LD50 is the lethal dose of a chemical that kills 50% of test animals, measured in mg/kg of body mass. 2. TLV is the threshold limit value—an estimate of the average concentration safely tolerated repeatedly during an 8-h period on a daily basis, measured in ppm or mg/m3.
Literature Cited 1. Brown, T. L.; LeMay, H. E., Jr.; Bursten, B. E. Chemistry: The Central Science, 10th ed.; Pearson/Prentice Hall: Upper Saddle River, NJ, 2006; p 50. 2. Chemical Safety Information—Glossary, Oxford University. http://ptcl.chem.ox.ac.uk/MSDS/glossary/GLOSSARY.html (accessed Jan 2008). 3. Ball, D. J. Chem. Educ. 2004, 81, 1441–1449. 4. Hicks, O.; Martinez, E.; McGinty, R. L.; Sevcik, R. S. Chemvention: Toys for Chemical Education. In Abstracts of 231st National Meeting of the American Chemical Society; Atlanta, GA, March 2006; pp 26–30. 5. Web Elements Periodic Table Home Page. http://www.webelements.com/ (accessed Feb 2008); see also Periodic Table Live! http://www.chemeddl.org/collections/ptl (accessed Feb 2008).
Supporting JCE Online Material
http://www.jce.divched.org/Journal/Issues/2008/Apr/abs516.html Abstract and keywords Full text (PDF) Links to cited URLs and JCE articles Supplement Student handouts: An element table for students to annotate; Student instructions and game rules; Example scorecard
Instructor notes: Detailed instructions for construction of the periodic table game board; Instructor’s key for the element table
© Division of Chemical Education • www.JCE.DivCHED.org • Vol. 85 No. 4 April 2008 • Journal of Chemical Education
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