We describe a structured inquiry-based lesson about the human ear and sound that can lead to long-term retention of content knowledge and reduce the gender gap in science subjects. The lesson integrates the subjects of biology and physics for students about 15 years of age and is suitable with high or low pre-knowledge and for both genders equally. Students learn in hands-on experiments about sound formation and properties; the human outer, middle, and inner ear; and limits to human hearing, both natural and resulting from damage to the inner ear. This lesson is suitable for beginners in inquiry-based learning and teaching. It is designed as structured/level 1 inquiry-based science. The topic and how it is analyzed is provided by the teacher in the lesson material, but students are strongly invited to actively think about why they expect certain results to happen and how the results can be interpreted.

Introduction

Inquiry-based learning has long been proposed to result in long-lasting learning outcomes (Wilson et al., 2009; Minner et al., 2010). We designed a structured inquiry-based lesson on the topic of hearing for ninth-graders (age 15) that covers several core ideas of the Next Generation Science Standards (NGSS; Achieve, 2013). A long-lasting knowledge gain over at least 12 weeks and a reduction of the gender gap through the use of this learning material has been demonstrated (Schmid & Bogner, 2015a). Research has also revealed that the more effort students invested during the lesson, the better their learning scores (Schmid & Bogner, 2015b). The implementation of this short intervention is therefore suitable for teaching content to be remembered in the long term – an effect that is especially important when the content has everyday value, such as understanding how to protect one's hearing ability.

The material provided can be used en bloc or divided into four separate one-hour periods and therefore can be adapted to the school's and the teacher's needs. Students work on their own in small groups, using the workbook and other material provided, while the teacher steps out of the spotlight – a typical approach for student-centered teaching. However, he or she is always there if the students have questions. Answering questions is not what the teacher does. He or she gives the students feedback – for example, by asking them questions on their procedure and their understanding until they realize the answer to their question on their own. The workbook is divided into four main stations. Each station contains background information on a topic and leads to instructions for an experiment. Because this learning material is designed as structured inquiry-based learning, the focus of student autonomy is laid on interpretation: What does the experiment prove? How does it prove it? What do the results mean in the context of the topic? The texts are filled with everyday experiences to reach a higher level of meaning for the students' life.

It is important to understand the different levels of inquiry-based learning when planning lessons. There are four levels (0–3) that indicate the extent to which students are given autonomy in their learning (Blanchard et al., 2010): level 0 (verification), level 1 (structured), level 2 (guided), and level 3 (open). For example, at level 0, the teacher decides the question to be investigated and the methods for analyzing and interpreting the results. In level 1, the interpretation of results is no longer decided by the teacher, but rather by the students themselves. Level 1, especially, suits students and teachers not yet familiar with inquiry-based learning. Lesson structure, procedure, timing, and outcome can be planned relatively well by the teacher, leaving little room for time stress or movement of students' ideas in a direction other than the one the teacher had in mind. Level 1 builds, for both teachers and students, a good basis for getting familiar with inquiry-based learning. Higher inquiry levels give even more autonomy to the learner, but this unfamiliar responsibility and freedom can overstrain both students and teachers. In higher-order inquiry-based teaching, students decide what phenomenon or topic they would like to work on or how to analyze a certain problem. While this is closer to real science, its outcome and time management are much less predictable (Sotiriou et al., 2017).

In empirically researching the “Hearing” module presented here, we found that the gender gap could be closed through use of structured-inquiry learning materials. Although boys had higher pre-knowledge than girls about the topic, both reached the same content knowledge by the end of the course and retained that level even after 12 weeks had passed. Both boys and girls had significant learning gains, and in addition to the content that both genders learned, girls were able to obtain during the module the knowledge that boys had brought to class as pre-knowledge. Inquiry-based learning is not especially suitable for either one gender or the other, but rather is helpful for disadvantaged learners in general because it reduces the barriers to learning. As students work autonomously in small, self-selected groups, those who feel less competent can become engaged to ask questions of their peers. There should be less (perceived) pressure, than there would be in front of the teacher or the whole class, that a certain question would, for example, be considered “stupid” to ask. Additionally, in small groups students with less self-confidence might become more prone to formulate ideas and hypotheses and thereby get more deeply involved in the topic.

Besides reducing the pressure of the classroom atmosphere, inquiry-based learning material starts with basic information to bring everyone to the same information level before starting exploration of an experiment and its outcomes. The questions raised in the workbook for the hearing module come in small steps, such that important information is processed and understood by the students before the next piece of information or conclusion is asked for. This ensures that students form a solid basis of knowledge that the lesson can build on. Again, the student-centered learning style puts the students in charge of their own learning. They can answer the questions only when they have read and understood the information given and the experiments provided. Active thinking by the learner is the crucial part of inquiry-based teaching. The autonomy students are given apparently motivates them to engage their energy in learning. The more effort students invested during the hearing module, the greater their learning outcomes were. The rotation of the four tasks of reading text, fetching experimental setups, conducting the experiment, and writing down the group's answer facilitates the active participation of shy students in all areas of the learning activity and hinders more assertive students from taking over the more “exciting” parts dominating the team.

The Hearing Module

Student Objectives

In the module described below, students are anticipated to learn content knowledge about the ear and sound. The focus of the learning environment is on taking responsibility for their own learning progress. Students should realize that only their own effort will bring them answers, as their teacher will not give direct answers but rather will guide students to finding answers on their own. The provided texts, hands-on experiments, and questions to be answered provide information, motivate students to engage in and understand scientific procedures, and lead to the formation of long-term content knowledge.

Setup & Materials

The structured inquiry-based instruction in this module requires about three hours. A regular classroom with movable tables for group work is sufficient. The teacher will need to copy the workbook for each student and purchase the required material for the hands-on experiments. Most of the equipment needed is inexpensive and readily available. The more expensive equipment consists of one laptop or PC per group of four students, equipped with the free software Visual Analyser and some kind of word processing software. Two identical mounted tuning forks are also needed. A detailed list of the materials, as well as the workbook in a student and a teacher version (including answers), is provided in the Supplemental Material with the online version of this article.

The teacher first introduces the inquiry lesson by announcing that the topic is hearing and sound and that the students will have the opportunity to discover this topic through structured inquiry. The underlying proactive structure of the lesson begins right from the start. The class gets the task of forming groups of about four students each and arranging the tables accordingly. The teacher places a large box in front of the class, holding all the experimental material. The students will fetch and return the needed material on their own. Within their groups, the students begin to read their workbooks. Their first task is to give each group member a role, which will rotate between group members after each experiment. This ensures that everyone feels important and gets to be in charge of each role and that nobody can either lean back or try to dominate the team. The roles are (1) reading the text aloud, (2) fetching and returning material, (3) conducting the experiment, and (4) writing down the group's answer after discussion. The intervention is designed so that groups work in parallel and in the same order of learning stations.

Learning Stations

Below, the learning content of the hearing module is summarized in a short description of each of the four learning stations.

What is sound?

Station 1 covers the phenomenon of sound creation and transport (Figure 1). Additionally, the students discover the difference between noise and tone, and they learn about frequency and amplitude by conducting experiments with sound-visualizing software on PCs. The content is learned by reading texts and thinking about the outcome of five experiments they conduct.

Figure 1.

Experiments at station 1 (left to right): sound creation—rubber band guitar; sound travel—marked spiral in motion; sound properties—frequency and amplitude.

Figure 1.

Experiments at station 1 (left to right): sound creation—rubber band guitar; sound travel—marked spiral in motion; sound properties—frequency and amplitude.

The texts invite the students to wonder about a phenomenon, such as sound creation. After the phenomenon is introduced, the text asks students to conduct a simple experiment with, for example, a rubber band guitar. These experiments are easy to conduct but still demand that students think about what is happening and why. The rubber band guitar experiment comes with questions to be answered. Students need to form a hypothesis explaining what they think happens to the air particles around the rubber band. The text then provides follow-up questions like “Do air molecules and sound travel the same distance?” and “What does the frequency tell you about the pitch of a sound?” For each question, experiments are conducted by the students. They need to think about logical answers to small-step-formulated questions about their observations.

How do we hear?

At station 2, students read about the anatomy of the outer and middle ear and what happens when sound arrives there (Figure 2). The information of the sound wave is transmitted to movement of the eardrum. Through the lever system of the ossicles and transmission to a smaller surface, the oval window, the force of the vibration is increased before it enters the inner ear. Students conduct experiments about the lever amplification of the ossicles and about force concentration.

Figure 2.

Experiment at station 2: the lever system of the ossicles.

Figure 2.

Experiment at station 2: the lever system of the ossicles.

How do we distinguish frequencies?

At station 3, students learn about resonance and eigenfrequency of objects (Figure 3). Students conduct experiments with two tuning forks: when the first is hit, the second will resonate only under certain circumstances. This is the only experiment that all the student groups need to do either one after the other or together, because of the silence needed and the relatively high cost of the tuning forks. It is possible to use another room for this experiment to obtain a silent environment. Understanding resonance and eigenfrequency is important in learning about how the cochlea in the inner ear functions. Students read about its anatomy and work with a model of the basilar membrane, represented by a metallophone, to understand how the basilar membrane works.

Figure 3.

Experiments at station 3: (left) eigenfrequency and resonance; (right) the shape of the basilar membrane discovered with tuning forks and a metallophone.

Figure 3.

Experiments at station 3: (left) eigenfrequency and resonance; (right) the shape of the basilar membrane discovered with tuning forks and a metallophone.

The limits of hearing

At station 4, the natural limits of human hearing are introduced (Figure 4). Ultrasound and infrasound are described. Students explore the reasons for these phenomena by analyzing the metallophone as a model of the cochlea. Afterwards, hearing loss caused by very loud sounds is introduced, and possibilities for protecting one's hearing are given.

Figure 4.

Model of the basilar membrane at station 4, labeled for understanding the natural limits of hearing. Missing plates of the metallophone resemble broken hair cells, indicating hearing loss for certain frequencies.

Figure 4.

Model of the basilar membrane at station 4, labeled for understanding the natural limits of hearing. Missing plates of the metallophone resemble broken hair cells, indicating hearing loss for certain frequencies.

Alignment with NGSS

This intervention is designed for students in middle school, about 15 years old. It addresses several core ideas of the NGSS (Achieve, 2013). It best fits Physical Science with its performance expectations but also fits Life Science. The hearing module enables students to develop usable knowledge to explain real-world phenomena in physics and biology. It covers the performance expectations of several scientific practices. For example, students use models and experimental setups and analyze background information in relation to the results of their experiments; they interpret the data to construct explanations on their own. The main goal is to promote understanding of why and how experimental results and phenomena occur. In relation to PS1: Matter and Its Interactions, the module covers the structure and properties of matter. With its interdisciplinary design bridging biology and physics, it supports crosscutting concepts like “cause and effect; scale, proportion and quantity; energy and matter; structure and function” (Achieve, 2013, p. 47). Students analyze and interpret data, design solutions, and engage in gaining arguments from evidence. The module also teaches some aspects of energy (PS3: Energy) and wave properties (PS4: Waves and Their Applications in Technologies for Information Transfer). In regard to LS1: From Molecules to Organisms: Structures and Processes, the sub-ideas of “structure and function of cells” and “information processing within organisms” (e.g., MS-LS1-8) are covered when students learn about the anatomy and physiology important for the creation of hearing sensations in humans. The module covers all three main concepts of the NGSS: Science and Engineering Practices (major), Disciplinary Core Ideas (minor), and Crosscutting Concepts (major). It also can fit Engineering Design with its focus on student-centered problem solving and interpretation of results in relation to everyday phenomena. With its interdisciplinary character, the hearing module teaches biology and physics content while addressing scientific reasoning abilities in a student-centered format.

Further Research Reading

This structured inquiry-based intervention was accompanied by scientific questionnaires to evaluate its results, published in the studies cited below.

Study 1. Learning with the hearing module leads to sustainable long-term formation of content knowledge. Student learning was measured immediately after participation and again after two six-week intervals. Their knowledge level had dropped a bit after six weeks but then remained stable 12 weeks later, indicating that the students did not forget the content knowledge. The module is suitable for boys and girls, and for students who already know a lot or only a little about the topic. Boys knew more than girls before the course, but by the end of the intervention both genders had learned and were on the same level. This approach is therefore a useful option for reducing the gender gap in science classes (Schmid & Bogner, 2015a; this publication is available open access).

Study 2. To estimate reasons for the long-term effect, we correlated effort, lesson rating, and perceived competence for learning and subject grades with the learning achievement. We found that if students invested much effort in the lesson, their achievement was higher. Effort and long-term achievement depend on each other. Additionally, science grades are positively linked to long-term knowledge gain. However, knowing more about the topic beforehand was not linked to knowledge gain (Schmid & Bogner, 2015b; this publication is available open access).

Study 3. We wanted to test whether science motivation can be enhanced through the inquiry approach. We chose the “Science Motivation Questionnaire” (Glynn et al., 2011). However, the scale behaved unexpectedly when used for 15-year-old students. The subscales “career motivation” and “self-efficacy” were not influenced through the inquiry course. Self-determination changed over time; it rose, but after 12 weeks it had fallen below the starting value. We concluded that self-determination can be increased in the short term by the hearing module. Furthermore, we found that self-determination, rather than career motivation or self-efficacy, was probably the main variable underlying daily fluctuation (Schmid & Bogner, 2017).

Conclusion

Our structured inquiry-based hearing module covers sound creation, transport, and properties; the anatomy of the human ear; the hearing process and its natural limitations due to illness; and options for protecting hearing ability from loud sound impacts. It is student centered, shifting the source of information from the teacher giving facts and information to the students' self-directed learning through reading, thinking, and drawing conclusions from experiments and models. The lesson connects biology with physics and is aligned with the NGSS. It leads to long-lasting increases in content knowledge and can help reduce the gender gap in science. It is suitable for classes with mixed pre-knowledge of the topic and therefore for all types of students. With its low-budget design and flexible application spectrum (e.g., use of all stations consecutively or one station per day; no special room equipment needed), it should be possible to use the hearing module in all schools and with all class schedules.

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Supplementary data