One of the goals of the Science Education Against Drug Abuse Partnership (SEADAP) is to increase student knowledge about drugs through the implementation of an inquiry-based curriculum. A science teacher who was a participant in the SEADAP program served as a facilitator for middle school students participating in an after-school program to assist them with designing their own experiment using planarians (flatworms) exposed to caffeine, sugar, and an energy drink. Results indicated that the average velocity of the planarians in 1 mM caffeine, 1 mM sucrose, and 0.1% Monster Energy drink increased in comparison to their behavior in spring water. The students also learned that substances such as energy drinks can be lethal to planarians.

Introduction

Energy drinks are popular among teenagers and are consumed more frequently by them than by adults (Visram et al., 2016). Strangely enough, in the United States there are no limits on the amount of caffeine that an energy drink can legally contain (Rath, 2012). This is a major concern and problem for the health of youth because energy drink consumption can cause adverse health effects, including headaches, anxiety, heart palpitations, chest pain, increased heart rate, nausea, insomnia, anxiety, hallucinations, nervousness, breathlessness, and stomach aches (Pagán et al., 2009; Rath, 2012; Bernstein, 2014). In addition to caffeine, energy drinks contain large amounts of sugar, which can cause cavities, periodontal disease, diabetes, and obesity (Rath, 2012).

Making students aware of the dangers of energy drinks is important, and this was the motivation of a group of eighth-grade students who participated in an after-school program that examined the different effects that an energy drink could have on the human body. They did this through an experiment using planarians, a type of flatworm that displays mammalian-like responses when exposed to substances such as caffeine and sucrose (Rawls et al., 2011; Zhang et al., 2013). Energy drinks are readily accessible, associated with substance use, and consumed by teenagers (Terry-McElrath et al., 2014). The procedure designed and implemented by these students was unique to their inquiry about the effects of Monster Energy drink on planarians. The students hypothesized that caffeine, sucrose, and Monster Energy drink would affect the motility of planarians.

Purpose

The purpose of this student-organized investigation was to examine the motility of planarians via their velocity in different concentrations of sucrose, caffeine, and Monster Energy drink and determine the effect of these solutions on this organism.

Participants

This lesson is designed for a classroom of 25 students, and the teacher will need at least 30 minutes to set up all the materials for the investigation.

Instruction

During discussion with the teacher, students compared the human nervous system to the planarian nervous system and were introduced to how planarians can be used as a model for studying stimulus-response behavior (Appendix A; see Supplemental Material with the online version of this article). The students were then asked to predict how planarians will react when placed in solutions of caffeine and sucrose. They conducted experimental trials using caffeine and sucrose following the procedure shown in Appendix B (see Supplemental Material).

As pre-laboratory activities, before conducting the experiment they designed, these students had already conducted investigations using planarians, similar to those in SEADAP lessons 1, 2, and 3 (see https://medicine.temple.edu/sites/medicine/files/files/seadap_lesson_ plans.pdf). These SEADAP-related lessons allowed them to hypothesize and implement experiments using other substances, such as alcohol and nicotine, in addition to sucrose and caffeine.

Student Inquiry

After completing the pre-laboratory experiments, the students were asked to design their own experiment. To facilitate higher-order thinking, the teacher asked such questions as “What other solutions could be tested?” and “In the real world, what other combinations of substances would consumers use?”

The students considered observing the effects of caffeine in a popular soft drink on students, teachers, and staff. However, there were ethical considerations when trying to work with human subjects. They were able to videotape an interview of one staff member who was addicted to a popular soft drink and was advised by her doctor to reduce her intake.

The students wanted to gather more information related to a combination of solutions of caffeine and sucrose. In response to the questions above, a group of students created a new and different experiment using caffeine, sucrose, and Monster Energy drink. The students wanted the planarians to travel in one direction instead of crossing and recrossing grid lines of graph paper (as described in Appendix B; the authors provided input for the lessons in the SEADAP program, and the protocol in Appendix B was designed for lesson 3 as presented at https://medicine.temple.edu/sites/medicine/files/files/seadap_lesson_plans.pdf). Via trial and error, the students decided to measure a 5 cm distance (d) on a groove of a print developing tray. The teacher prepared the 10 mM stock sucrose solution and 10 mM caffeine solution; the Monster Energy drink started at 100% solution. The students made diluted concentrations (serial dilutions) of caffeine or sucrose from the 10 mM concentration stock solution prepared by the teacher.

Student-Designed Experiment

The students designed and implemented the following protocol (approximate periods of time required are shown in parentheses):

  1. Pour spring water into the groove of the print developing tray.

  2. Place a planarian in the groove.

  3. Record the time (t) it took for a planarian to travel 5 cm in the groove.

  4. Repeat the procedure for three trials using spring water with three different worms. (20 minutes)

  5. Repeat the procedure above, using caffeine at concentrations of 0.001 mM, 0.01 mM, 0.1 mM, 1 mM, and 10 mM for a total of three trials, with a different worm and a different concentration of caffeine for each trial. Change planarian between different concentrations so as not to affect the results. (25 minutes)

  6. Repeat the procedure, using sucrose at the same concentrations of 0.01 mM, 0.1 mM, 1 mM, and 10 mM for a total of three trials, with a different worm and a different concentration of sucrose for each trial. Change planarian between different concentrations so as not to affect the results. (25 minutes)

  7. Repeat the procedure, using Monster Energy drink at 0.01%, 1%, and 10% dilutions for a total of three trials, with a different worm and a different dilution of Monster Energy drink for each trial. Change planarian between different dilutions so as not to affect the results. (25 minutes) (The teacher showed the students how to calculate the dilutions of Monster Energy drink. The velocity [v] was calculated [v = d/t] for each of the three trials and the average velocity was determined.)

Results

During their experiment, the students observed some atypical behavior in the planarians. The behavior of some of the planarians was inconsistent and the students questioned whether room temperature affected the planarians or caused variation in the results, so they adjusted the temperature in the room to make it the same for all their experimental trials. Additionally, these middle schoolers learned not to shake the table while doing the experiment, since this could affect the results. They also thought the light in the room may have affected the planarian, so they kept the light the same for all trials. After taking the identified variables under consideration, the students decided to conduct three trials; the data points in the graphs represent the average velocity of their trials (Figures 1 and 2).

Figure 1.

Effects of sucrose and caffeine on planarians' motility.

Figure 1.

Effects of sucrose and caffeine on planarians' motility.

Figure 2.

Effects of Monster Energy drink on planarians' motility.

Figure 2.

Effects of Monster Energy drink on planarians' motility.

At the highest concentration/percentage of sucrose, caffeine, and Monster Energy drink, the planarians' velocity decreased, and stereotypical movement increased. The highest average velocity occurred at 1 mM concentrations of sucrose and caffeine. The planarians died at 1% and 10% Monster Energy drink dilutions. The highest average velocity of planarians in the energy drink occurred at 0.1% (Figures 1 and 2).

Assessment

This student investigation addressed a real-world problem and required higher-order thinking skills. The final products for assessment were a poster and an oral presentation. The teacher used a presentation rubric (Table 1) that includes the categories “Below Standard,” “Approaching Standard,” and “At Standard.”

Table 1.
Presentation rubric.
Below StandardApproaching StandardAt Standard
Explanation of Ideas & Information 
  • Uses too few, inappropriate, or irrelevant descriptions, facts, details, or examples to support ideas

 
  • Uses some descriptions, facts, details, and examples that support ideas, but there may not be enough, or some are irrelevant

 
  • Uses relevant, well-chosen descriptions, facts, details, and examples to support claims, findings, arguments, or an answer to a driving question (CC 6-8.SL.4)

 
Organization 
  • Does not include important parts required in the presentation

  • Does not have a main idea or presents ideas in an order that does not make sense

 
  • Includes almost everything required in the presentation

  • Moves from one idea to the next, but main idea may not be clear or some ideas may be in the wrong order

 
  • Includes everything required in the presentation

  • States main idea and moves from one idea to the next in a logical order, emphasizing main points in a focused, coherent manner (CC 6-8.SL.4)

 
Eyes & Body 
  • Does not look at audience; reads notes or slides

  • Does not use gestures or movements

  • Lacks poise and confidence (fidgets, slouches, appears nervous)

  • Wears clothing inappropriate for the occasion

 
  • Makes infrequent eye contact; reads notes or slides most of the time

  • Uses a few gestures or movements but they do not look natural

  • Shows some poise and confidence (only a little fidgeting or nervous movement)

  • Makes some attempt to wear clothing appropriate for the occasion

 
  • Keeps eye contact with audience most of the time, only glances at notes or slides (CC 6-8.SL.4)

  • Uses natural gestures and movements

  • Looks poised and confident

  • Wears clothing appropriate for the occasion

 
Voice 
  • Mumbles or speaks too quickly or slowly

  • Speaks too softly to be understood

  • Frequently uses filler word (“uh,” “um,” “so,” “like,” etc.)

 
  • Speaks clearly most of the time

  • Speaks loudly enough for most of the audience to hear but may speak in a monotone

  • Occasionally uses filler words

 
  • Speaks clearly, not too quickly or slowly (CC 6-8.SL.4)

  • Speaks loudly enough for everyone to hear; changes tone to maintain interest (CC 6-8.SL.4)

  • Rarely uses filler words

 
Presentation Aids 
  • Does not use audio/visual aids or media

 
  • Uses audio/visual aids or media, but they sometimes distract from or do not add to the presentation

 
  • Uses well-produced audio/visual aids or media to clarify information, emphasize important points, strengthen arguments, and add interest (CC 6-8.SL.5)

 
Response to Audience Questions 
  • Does not address audience questions (goes off topic or misunderstands without seeking clarification)

 
  • Answers some audience questions, but not always clearly or completely

 
  • Answers audience questions clearly and completely

 
Participation in Team Presentation 
  • Not all team members participate; only one or two speak

 
  • All team members participate, but not equally

 
  • All team members participate equally

 
Below StandardApproaching StandardAt Standard
Explanation of Ideas & Information 
  • Uses too few, inappropriate, or irrelevant descriptions, facts, details, or examples to support ideas

 
  • Uses some descriptions, facts, details, and examples that support ideas, but there may not be enough, or some are irrelevant

 
  • Uses relevant, well-chosen descriptions, facts, details, and examples to support claims, findings, arguments, or an answer to a driving question (CC 6-8.SL.4)

 
Organization 
  • Does not include important parts required in the presentation

  • Does not have a main idea or presents ideas in an order that does not make sense

 
  • Includes almost everything required in the presentation

  • Moves from one idea to the next, but main idea may not be clear or some ideas may be in the wrong order

 
  • Includes everything required in the presentation

  • States main idea and moves from one idea to the next in a logical order, emphasizing main points in a focused, coherent manner (CC 6-8.SL.4)

 
Eyes & Body 
  • Does not look at audience; reads notes or slides

  • Does not use gestures or movements

  • Lacks poise and confidence (fidgets, slouches, appears nervous)

  • Wears clothing inappropriate for the occasion

 
  • Makes infrequent eye contact; reads notes or slides most of the time

  • Uses a few gestures or movements but they do not look natural

  • Shows some poise and confidence (only a little fidgeting or nervous movement)

  • Makes some attempt to wear clothing appropriate for the occasion

 
  • Keeps eye contact with audience most of the time, only glances at notes or slides (CC 6-8.SL.4)

  • Uses natural gestures and movements

  • Looks poised and confident

  • Wears clothing appropriate for the occasion

 
Voice 
  • Mumbles or speaks too quickly or slowly

  • Speaks too softly to be understood

  • Frequently uses filler word (“uh,” “um,” “so,” “like,” etc.)

 
  • Speaks clearly most of the time

  • Speaks loudly enough for most of the audience to hear but may speak in a monotone

  • Occasionally uses filler words

 
  • Speaks clearly, not too quickly or slowly (CC 6-8.SL.4)

  • Speaks loudly enough for everyone to hear; changes tone to maintain interest (CC 6-8.SL.4)

  • Rarely uses filler words

 
Presentation Aids 
  • Does not use audio/visual aids or media

 
  • Uses audio/visual aids or media, but they sometimes distract from or do not add to the presentation

 
  • Uses well-produced audio/visual aids or media to clarify information, emphasize important points, strengthen arguments, and add interest (CC 6-8.SL.5)

 
Response to Audience Questions 
  • Does not address audience questions (goes off topic or misunderstands without seeking clarification)

 
  • Answers some audience questions, but not always clearly or completely

 
  • Answers audience questions clearly and completely

 
Participation in Team Presentation 
  • Not all team members participate; only one or two speak

 
  • All team members participate, but not equally

 
  • All team members participate equally

 

The students were also administered a test after SEADAP lessons 1, 2, and 3 were implemented and after the completion of the sucrose, caffeine, and Monster Energy drink investigation (see Appendix E in the Supplemental Material). The questions addressed student knowledge about the science of drug addiction, awareness about the care and use of animals in basic science research, and awareness about biomedical research careers. On average the students answered nine of the 12 questions correctly after participating in class discussion and conducting experiments.

The students also designed and developed their investigations to participate in their school science fair. Their research was evaluated according to the science fair criteria, which included purpose/objective, contribution to the field of science, adherence to scientific method, research plan, data collection, and analysis. They were also evaluated on having clear graphs, tables, visuals, reproducibility of results, appropriate use of mathematical and statistical methods, sufficient data which support interpretation and conclusions, creativity, oral presentation, and organized materials.

Discussion

The most popular laboratory style of instruction has been to provide “cookbook”experiments to conduct in the science classroom (Domin, 1999). In many such activities, students are given predetermined protocols and have no opportunity to provide their own design input or to realize the relevance of the scientific activity to familiar experiences. Here, by contrast, an investigation was uniquely designed and implemented by eighth-graders who found that the motility and survival of planarians was affected by caffeine, sucrose, and Monster Energy drink in comparison to spring water. In addition to sugar and caffeine, the students also talked about the panax ginseng root and yerba mate stimulants found in Monster Energy drinks; they discussed how these stimulants could also cause a rise in motility of the planarian. The student research experience also allowed them to gain a better understanding of the scientific process. They developed communication skills, learned how to work collaboratively, and presented to various audiences – including a 4-H presentation, an e-cybermission online science fair competition, as well as school, regional, and state science fair competitions at which they earned awards.

These students also learned about the similarities between the complex human and the simple planarian nervous systems and saw that energy drinks can be lethal to worms, especially at high concentrations. One student said, “Planaria have a similar nervous system as us, they react like us when we have consumed a substance: motor skills are affected and death may occur.” They realized that they could study and observe planarians to also learn about how caffeine, sucrose, and Monster Energy might affect other organisms. Another student said, “Since the planarians react almost the same ways as humans do, we can learn a lot … by watching the worms.” Finally, one student seemed to have an “aha moment” about the adverse effects related to the consumption of energy drinks by teens. He said, “Sugar and caffeine are drugs that can have serious effects. Energy drinks, containing both, should not be consumed by kids because our brains are not fully developed yet.” This student recognized that energy drinks can be dangerous to his peers. These students raised their awareness about the toxic effects of energy drinks, which is an important revelation for students and middle school science teachers alike (Visram et al., 2016). This inquiry-based laboratory activity met an NGSS standard (see Appendix C in the Supplemental Material), and middle school students learned about how substances can directly and negatively affect an organism.

Supplemental Material (available with the online version of this article)

Appendix A: Planaria Model

Appendix B: Introductory Student Laboratory Investigations

Appendix C: Correlation with NGSS Standard MS-LS1-1

Appendix D: Learning Objectives & Assessment Criteria

Appendix E: Student Assessment Test Questions

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Supplementary data