Chemistry for Everyone
The Student-to-Student Chemistry Initiative: Training High School Students To Perform Chemistry Demonstration Programs for Elementary School Students Phillip D. Voegel,* Kathryn A. Quashnock, and Katrina M. Heil Department of Chemistry, Midwestern State University, Wichita Falls, TX 76308-2099; *
[email protected] Outreach in science and, specifically, in chemistry is not a new concept (1). Outreach programs include chemistry camps (2–4), science competitions (5), science fair mentoring (6), and demonstration programs. Most chemistry demonstration programs involve college students and faculty performing demonstration experiments either on college campuses or at primary and secondary schools. Typical audiences include elementary (7–12), middle school (13, 14), and high school students (15–18). In a few reported programs, high school students under the direction of their teacher perform chemistry demonstrations at local schools without input from college faculty or students (19–21). The Student-to-Student Chemistry Initiative (SSCI) focuses on both elementary and high school students. High school students visit Midwestern State University (MSU) for training and later visit elementary schools to perform chemistry demonstration programs. SSCI’s impact on high school students is evaluated. The program’s effect on elementary school students will be evaluated in another publication. Program Origins and Objectives As a small chemistry program, MSU lacks the personnel to present demonstration programs to the majority of fifth grade students in our local school district (Wichita Falls Independent School District, WFISD) by the conventional approaches described above. Prior to the SSCI program, 200–300 fifth grade students annually attended MSU chemistry outreach programs, representing less than 25% of fifth grade students in the district. While the largest, WFISD is only one of forty school districts served by the Texas Education Agency (TEA) Region IX Service Center, located in Wichita Falls. Students in the other districts could not effectively participate in our earlier outreach programs. In addition, high school students were not invited to participate in our previous demonstration programs. SSCI is designed to meet two objectives: to increase the number of students affected by MSU chemistry outreach programs over an expanded geographic area and to positively affect student perceptions of science. Identical preparticipation and postparticipation surveys (Figure 1) are completed to evaluate the program’s effectiveness in changing students’ perceptions. The surveys address attitudes toward science, interest in science careers, and the development of scientific awareness. Interest in attending MSU is evaluated for high school students only. Students indicate their agreement with each statement (four questions for each area evaluated). The scores for each area, after accounting for negatively worded statements (e.g., statement 8 in Figure 1), are summed. Average pre- and postparticipation scores are compared using
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the null hypothesis at the 95% confidence level. The t-test is applied to paired and unpaired results to determine the p values. Most published chemistry outreach programs evaluate success based on the number of students in attendance or by anecdotal evidence. One report includes a four question postparticipation survey (12).
MSU Student-to-Student Chemistry Initiative Preparticipation Survey for High School Students Please circle a number for each question. If you strongly agree with a statement circle 5. If you strongly disagree with a statement circle 1. If you are somewhere in between, then circle 2, 3, or 4. 1. I would not want to work in science after I graduate. 1 2 3 4 5 2. I enjoy learning about science. 1 2 3 4 5 3. I want to go to a school like MSU. 1 2 3 4 5 4. Chemistry plays a role in making my car go. 1 2 3 4 5 5. I want to be a scientist when I graduate. 1 2 3 4 5 6. Acid rain does not exist. 1 2 3 4 5 7. I am very interested in going to MSU. 1 2 3 4 5 8. Science is boring. 1 2 3 4 5 9. Science is not a career I would like. 1 2 3 4 5 10. MSU is not the right college for me. 1 2 3 4 5 11. I have never used a polymer. 1 2 3 4 5 12. Science experiments are fun. 1 2 3 4 5 13. Being a scientist is my career goal. 1 2 3 4 5 14. I have heard of global warming. 1 2 3 4 5 15. I am not considering going to MSU. 1 2 3 4 5 16. I never find science interesting. 1 2 3 4 5 Figure 1. SSCI survey form.
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Chemistry for Everyone
Program Description Chemistry teachers from the 43 high schools in TEA Region IX are invited to participate in SSCI. The teachers independently select students for the program. Selection criteria range from whole chemistry classes to science club volunteers. For most students, prior exposure to chemistry is limited since SSCI begins about three weeks into the academic year. High school students and their teachers attend a 90-minute training session at MSU, where students complete the preparticipation survey. MSU students and faculty then perform each demonstration experiment. The chemical concepts involved in the demonstration are discussed along with topics linking the concepts to common experiences and ideas. The experiments used in SSCI are typical of those used in other demonstration programs. A methanol cannon illustrates combustion reactions (ref 22; a film canister replaces the 500-mL bottle to improve safety). The effect of particle size on the rate of chemical reaction is discussed and linked to the use of kindling in starting campfires and the functioning of automobile engines. Guncotton (nitrocellulose) is ignited using a heated glass rod (23). A cloud is formed in a two-liter soft drink bottle (24). Endothermic and exothermic reactions are demonstrated by the respective dissolutions of NH4NO3 and CaCl2 in sealed zipper bag (25, 26). Acid– base chemistry is demonstrated by adding small quantities of 0.1 M NaOH and 0.1 M HCl to water containing metacresol purple, an indicator. A stopper rocket race is held in which three test tubes containing a few drops of metacresol purple are partially filled with 0.03 M HCl (red), deionized water (yellow), and 0.03 M NaOH (purple), respectively. Small pieces of an antacid tablet containing bicarbonate are added simultaneously to each test tube and the tubes are stoppered. Carbon dioxide forms in all three cases eventually expelling the stoppers. The amphoteric nature of bicarbonate, noted from the yellow color of the indicator at the completion of the experiment in all three tubes, is discussed. The nature and many uses of polymers are discussed while preparing slime (27) and while demonstrating the difference in aqueous solubility of two common packing materials, polystyrene and modified starch. Chemiluminescence is demonstrated with the reaction of luminol and peroxide (28). Pouring the separate solutions simultaneously into a funnel placed in a Graham condenser (spiral inner tube) enhances the visual effect of this reaction. After each experiment has been demonstrated, at least one student from each school repeats the experiment. Safety and disposal issues are examined for each experiment. The use of goggles is required for all demonstration experiments. Students tour the chemistry department and a presentation on careers in science and related academic preparation is given. Students end the training portion of SSCI by completing the postparticipation survey. Each high school receives a kit containing supplies and reagents necessary to complete a demonstration performance. Kits include goggles, flasks, beakers, a film canister methanol cannon with piezoelectric starter (29), disposable cups and pipets, plastic zipper bags, glass rods, a single-use camera, and a chemiluminescence reactor. The chemiluminescence reactor is prepared by wrapping flexible vinyl tubing around an 18 in. section of rigid 1 in. diameter tubing mounted on a 682
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ring stand and provides the same effect as the Graham condenser at a lower cost. Detailed instructions for each experiment and a suggested script are included. The cost for each kit is about $36 and replacement of reagents and disposable supplies is under $8. While not provided in the kit, participating high schools are required to have a fire extinguisher on hand during their demonstration program. This is of particular importance when demonstrating combustion reactions using guncotton and the film canister methanol cannon. Most high school teachers continue the training during after-school practice sessions. Many also wait four to eight weeks before presenting demonstration programs at the elementary school allowing high school students to obtain a better understanding of the chemistry involved. High school teachers schedule 50-minute performances at their local elementary schools. Elementary school students take both active and passive roles during the program. Some experiments allow hands-on participation by student volunteers, while others allow all students to make observations. Students participating in hands-on experiments are required to wear safety goggles. Results and Discussion The goal of increasing the number of students affected by our outreach program over an expanded geographic area was readily met. During the program’s first academic year, 80 high school students from 10 schools participated and 1618 elementary school students attended chemistry outreach demonstrations. This represented more than a five-fold increase in attendance by elementary school students. Implementation of SSCI increased the geographic area influenced by MSU outreach programs. The distance from MSU to each of the participating high schools, their respective student populations, and number of SSCI participants are shown in Table 1. Chillicothe and Throckmorton represent two of the most distant districts in TEA Region IX. No consistent differences were observed in the survey results when comparing responses based on enrollment (data not shown). Seventy-eight preparticipation and 72 postparticipation surveys were analyzed. Two preparticipation surveys and eight
Table 1. Participating High School Information School District
Distancea/ miles
Total Enrollment
SSCI Participants
Archer City
21
169
6
Burkburnett
17
984
5
Chillicothe
64
77
5
Gold-Berg
44
43
7
Harrold
34
36
2
Henrietta
17
328
6
Holliday
11
309
1
Iowa Park
12
628
14
Rider, WFISD
3
1618
20
Throckmorton
61
68
14
a
Distance from MSU.
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postparticipation surveys were incomplete and were excluded. On a voluntary basis, students placed their names on the surveys. Thirty-four pre- and postparticipation surveys could be identified as belonging to a particular student and statistical analysis, including the paired t-test, were performed on these surveys. Analysis of Unpaired Results The average scores in each of the four evaluation areas are given in Table 2 for all students. In all four areas, increased survey scores are observed, with an average increase of 0.8. Only in the area of scientific awareness is the increase statistically significant based on the null hypothesis with 95% confidence and the unpaired t-test (p < 0.01). The unpaired t-test was performed on the scores for each evaluation area. The resulting p-values are shown in Table 2. The low scores observed on the preparticipation survey for interest in careers in science show an area where our program could have a significant impact on student attitudes. However, the small increase in these scores and its lack of statistical significance demonstrate SSCI’s lack of effectiveness in this area. Based on these findings, to increase interest in science careers, this portion of the program must be improved, or new outreach programs developed. The survey statements are designed to elicit specific responses. For statements using positive terminology (e.g., statements two and five in Figure 1), the expected responses are five, strong agreement. For statements employing negative phrasing (e.g., statements one and eight in Figure 1), the expected responses are one, strong disagreement. The percentage of students providing either the expected responses or the converse responses to all four statements within one evaluation area is presented in Table 3. The percentage of students responding in the expected manner increases by 34.5% and 8.8% in the areas of scientific awareness and general attitude toward science, respectively. Prior to participation in SSCI, no students respond in the expected manner to all four statements regarding interest in science careers and only 1.4% do so after participation. Students providing converse responses regarding interest in science careers also increases following participation. Like the comparison of pre- and postparticipation average scores, these data suggest the need to improve our outreach programs intended to interest high school students in science careers.
Conclusion The Student-to-Student Chemistry Initiative is successful in meeting its goal of increasing the number of students participating over an expanded geographic area. SSCI demonstrates the ability to multiply the effects of our outreach program by enlisting the aid of high school students thus increasing the personnel available for reaching the elementary schools. SSCI successfully trains high school students to perform chemistry demonstration programs and provides the
Table 2. Statistical Analysis of All Student Data Survey Evaluation Area
Preparticipation
Postparticipation
p
General attitude toward science
16.1 ± 0.9
16.6 ± 0.8
0.20
Interest in science careers
11.2 ± 1.1
11.6 ± 1.0
0.25
Scientific awareness
16.0 ± 1.2
17.8 ± 0.7
