Introducing mechanical and material properties to first-year engineering learners through intuitive physical demonstrations involving oscillators and tuning forks

Abstract

Introducing mechanical and material properties in engineering curriculum is critical for developing core competencies and foundational to material selection for design. To reinforce learning, these concepts are often taught alongside laboratories. However, for large first-year engineering classes, this can introduce challenges regarding resources and infrastructure, as these concepts are often taught through destructive tests (e.g., tensile testing) that require specialized equipment, run by laboratory leads in a demonstrative manner, thereby limiting hands-on opportunities. To further supplement these educational methods, this work presents interactive, low-cost laboratory activities that use oscillating rulers in a cantilever beam setup and tuning forks as harmonic oscillators to introduce mechanical and material properties, specifically Young's modulus. By linking oscillatory behaviour to mechanical properties, learners explore how stiffness influences natural frequency and pitch, connecting classroom theory to everyday phenomena and different instruments. The activities are designed to complement lecture material, providing an intuitive, non-destructive, and hands-on approach to learning. Implementing these innovative labs highlights the broad opportunities for educators to incorporate interdisciplinary topics into course-based content, complementing current curricula. With evolving pedagogies, material selection in mechanical design should not be overlooked, and educators must consider how to adapt and improve traditional material-selection practices for the next generation.

Keywords

Tuning fork mechanical properties elastic modulus physical demonstrations experiential learning

Introduction: Background and rationale for the educational activity innovation

In mechanical design, careful consideration of mechanical and materials properties in materials selection plays a crucial role, critical to the success of a given product. However, while learning about these properties is foundational to mechanical engineering education, this is often taught relying on traditional educational lecture styles to convey abstract knowledge effectively to reach a large audience.^1,2 While this teaching style is effective for educators in these large settings, solely relying on lecture-based education provides limited opportunities for learners to practice these skills and explore their physical application. To address this, engineering education trends are shifting towards pedagogical strategies prioritizing problem-based experiential learning opportunities that actively engage learners.^3–10

Experiential learning approaches are described as ‘learning by doing’ teaching methods that actively engage learners through experience-based learning approaches.¹¹ This can involve integrating real-life problems in the classroom and/or laboratories, which aid in developing problem-solving skills.¹⁰ Integrating experiential learning teaching methods can lead to benefits such as increased learner engagement, perceived learning, and learner motivation.^3–5 These methods are often associated with immersive physical experiences, but can also be introduced successfully in a virtual setting through software, augmented reality, games, simulation-based technologies, etc.^12,13 Along with experiential learning is the concept of active learning, where educators involve learners directly in taking action within their educational experience, relying on elements of reflection, often in a cooperative learning setting.^14,15 Research where cooperative active learning strategies were implemented noted improvements in learner performance failure rate reduction, concept comprehension, and overall education experience improvement.^7,16 Thus, including active and experiential learning strategies where students can contextualize their learning together and are provided with a more hands-on approach is anticipated to increase student engagement and give students the confidence to tackle complex, open-ended, and multi-disciplinary engineering challenges.

When discussing learning styles in experiential learning, the educational implementation of the designed activities introduced in this manuscript most closely mimics Kolb's 4-Stage learning cycle in the laboratory learning environment.^17,18 Traditionally, Kolb's learning cycle stages include concrete experience, reflective observation, abstract conceptualization, and active experimentation.^17,18 Our adaptation of the Kolb learning cycle is illustrated in Figure 1, which is utilized in our teaching and within this work presented herein. Within the engineering labs presented, the concrete experience is actively carried out in the laboratory through the activities described. There are also portions of the laboratory where learners reflect on their actions (reflective observation) through question-and-answer periods with teaching staff and collaborative activities. The laboratory manual and assignment are further designed to push learners to deepen their understanding of the concepts introduced (abstract conceptualization). Finally, learners apply the theories they have learned to solve a problem within the assignment and in the laboratory (active experimentation). Kolb also assigns four different learning styles to each category: diverger, assimilator, converger, and accommodator. Figure 1 also has overlapping connections with the Belhot Learning cycle¹⁹ to the Kolb learning cycle illustrated. It demonstrates how this form of education can accommodate and foster participation among different learning styles, while also encouraging active learning.

Figure 1.

Kolb learning cycle adaptation. Kolb Learning Cycle adapted with four learning styles contextualized with the workflow of this laboratory exercise.

The goal of this paper is to showcase our methodology and support other instructors in adopting the laboratory approach taken. A literature review by Tembrevilla et al. (2023) highlighted several critical developments in experimental learning and research surrounding it in the late twentieth century.²⁰ Examples of crucial moments include the creation of the European Society of Engineering Education in 1973, the first World Congress on Educating Engineers for World Development in 1976, and the formation of the Engineering Education Coalition in 1989.²⁰ Experiential education-based engineering programs are becoming more prominent; some pioneering programs include Worcester Polytechnic Institute PLAN, the University of Massachusetts ESIC (Engineering Services for Industry and Community) and the University of Cincinnati Professional Practice Program.²⁰ Examples of newer programs include McMaster University's (Hamilton, ON, Canada) ‘PIVOT’, which restructured the first-year engineering program. This paper's laboratory methodology was designed for ‘Integrated Cornerstone Design Projects in Engineering’ or simply ENG 1P13, which came out of McMaster's PIVOT.²¹

This helps meet a growing need to update engineering educational programs and adapt to the twenty-first century,¹ by exploring exciting new opportunities to teach first-year learners about mechanical and material properties in a non-traditional manner using experiential learning. Herein, a fresh approach to teaching the mechanical properties of materials is introduced, utilizing unconventional new laboratory exercises that focus on the oscillation of materials with broad applications across various engineering fields.

Scope of study & learning environment

As a part of this initiative, this work highlights the development of a new learner-centred, experiential laboratory to teach essential mechanical and material properties concepts related to mechanical design, notably the modulus of elasticity or Young's Modulus, to first-year engineering undergraduate students in a fun, interactive manner. These activities were successfully introduced within McMaster University's 1P13 course during the 2021–2022 academic year, which included 906 first-year engineering students who typically participated in these activities during laboratories with a maximum of 25 learners per group.

Traditionally, this topic is taught through lecture-based content and further reinforced through laboratories that involve analyzing the mechanical behaviour of a material studied through a tensile test. In this test, a material is pulled, exposed to an applied tensile load until failure, and then an engineering stress-strain curve is produced for analysis. While these tests remain a foundation for learning materials engineering concepts, for large first-year engineering classes, these laboratories often introduce challenges regarding resources and infrastructure, as tensile testing requires specialized equipment to break samples. Thus, these laboratories are typically demonstrative in nature, where the laboratory leader tests a limited number of samples in front of a group of learners, thereby limiting hands-on opportunities for learners.

To further supplement these educational methods, this work presents creative instructional methods to teach these concepts using interactive, low-cost laboratory activities involving oscillators, notably tuning forks like those used in musical and other applications, to introduce concepts of material mechanical behaviour. The lab connects the theory behind how tuning forks work to applications where they are used in their everyday lives, outside of just music, aiding in teaching learners the importance of Young's Modulus in materials selection for mechanical design. The laboratory focuses on three main components: A) theory, B) connection, and C) practice (Figure 2). First, learners are exposed to the science or theory behind tuning forks, relating to oscillatory mechanics and Young's Modulus (Figure 2A). Laughlin et al. explain in their work acoustic properties of materials with tuning forks directly relates to Young's Modulus and inversely to density.²² Then, before diving into the activity, the theory is connected to everyday examples of where oscillators such as tuning forks are used from the macro, meso, to micro and nano scales (Figure 2B), contextualizing the educational experience through applications relevant to their lives. Finally, theory is connected to practice in experiential learning during the laboratory activity through hands-on testing (Figure 2C). Here, learners apply what they have learned to hypothesize which tuning fork will have the highest pitch based on what material it is made from, aiding learners to explore how materials selection plays a role in mechanical design (Figure 2C).

Figure 2.

Connecting theory to practice: demystifying how tuning forks work. Overview of the tuning fork laboratory components subdivided into three key components involving: (A) theory or scientific principles being taught, emphasizing mechanical oscillation and Young's Modulus, (B) connection element where the activity is contextualized through relevant everyday applications, (C) practice component with hands-on experiential learning activities with a virtual data processing component.

Herein, in this work, we present a novel approach to introducing fundamental mechanical and materials concepts using tuning forks and oscillatory principles, applicable to a wide range of real-world problems. This introduces a beneficial interdisciplinary approach in their education,²³ touching on multiple concepts, including mechanical, materials, and musical themes. Laboratory learning objectives for this laboratory, titled “Scientific Principles of Mechanical Structures and Devices,” are summarized in Table 1. The described laboratory is designed for in-person settings, although it can be adapted for virtual learning, making it accessible to educators teaching remotely and to institutions adopting virtual laboratories in the long term.²⁴ Furthermore, the activities are designed to be design-driven (top-down approach) for engineering materials education, as opposed to the traditional science-driven (bottom-up approach).²⁵ Finally, in developing these low-cost, non-destructive activities involving oscillators and tuning forks to reinforce these learning concepts, we have 1) increased the accessibility of these activities, allowing for every learner to have a hands-on experience, 2) created related experiences for learners to connect to their daily lives, 3) taught concepts in a different way that may ‘resonate’ with some learners more, and 4) established non-destructive and reuseable activities for educational purposes.

Table 1.

Overview of laboratory learning objectives and how these are achieved within the activity presented.

Materials science lab: scientific principles of mechanical structures and devices
Learning Objectives – What are learners leaving with at the end of the laboratory?	Implementation – How are these learning objectives achieved?
(1) Review lesson on stress-strain concepts	(1) Laboratory slides; tuning fork and oscillator activities
(2) Introduce essential concepts related to mechanical properties of materials, notably Elastic Modulus	(2) Tuning fork and oscillator activities
(3) Teach learners about materials property charts and introduce the foundations of material selection	(3) Tuning fork and oscillator activities, Ansys EduPack
(4) Work as a team to apply concepts to an assignment focusing on these concepts, notably: stress-strain, Young's Modulus, and material property charts	(4) Laboratory assignment

Educational relevance & scientific background

Before introducing the lab activities, educational relevance and scientific principles are briefly introduced to contextualize the lesson material. The laboratory focuses on key mechanical material properties, such as Young's Modulus, that relate to the acoustic properties of materials and highlights their use in oscillatory applications, such as in a tuning fork.

The lesson is contextualized through a discussion on how oscillatory applications are used in the daily lives of learners in the lab. One particularly relatable application provided to learners is crystal oscillators used in digital clocks, which feature tiny tuning forks made of quartz. These are shown by the lab leads in a hands-on manner, where learners dissect digital clocks provided to show these tiny tuning forks within the circuit boards. The lab leads discuss that vibrating this tiny crystal tuning fork to create an electrical signal with a precise vibrational frequency is how digital clocks keep track of time, where a frequency of 2¹⁵ = 32,768 Hz is used for timekeeping, which is convenient for binary numbers, and its division allows for precise timekeeping.²⁶ The piezoelectric effect is a phenomenon observed in different materials in which the materials produce an electric charge proportional to the mechanical stress applied to the sample.²⁷ Such crystal oscillators keep track of time utilizing the piezoelectric effect. Since the material is in the presence of an electric field, a mechanical strain forms on the crystal, causing the crystal to vibrate at specific cycles, the circuit keeps track of these vibrations, and the circuit itself is a tiny tuning fork.

Other applications that rely on similar oscillatory mechanical-material concepts are discussed with learners from a multiscale perspective, where they are asked: Where are tiny tuning forks in our lives? A larger-scale, macro application that relies on oscillatory concepts includes tuning forks for musical applications, highlighted for learners as a topic bridge-in prior to this activity (discussed later). Another application that can be brought up involves biomedical research, where the stability of a dental implant can be measured using resonance frequency analysis, whereby a device measures the vibration of the implanted device (akin to a tuning fork), which can be correlated to its integration into bone.²⁸ At the micro/nano level, atomic force microscopes (AFM) use a piezoelectric scanner paired with a sharp probe tip. The AFM probes the surface of a sample with the sharp tip (often less than 100 Å in diameter), and the force between the tip and the sample surface causes the cantilever to bend or deflect. The AFM utilizes a detector to measure the deflection to generate a surface topography of the sample.^29,30

Once contextualized, a brief scientific background on Young's Modulus E is provided, directly related to materials’ mechanical and acoustic properties. Young's Modulus E is the ratio of elastic axial stress σ to elastic axial strain ε measured along the same axis.³¹ When teaching learners about elasticity, it is highlighted that bonds between atoms can be represented as small springs.

At the atomic level, atoms are bonded together via various types of attractive forces (e.g., ionic, covalent, metallic and secondary bonds) and, based on their stress state, energy (U) may be stored in these bonds.³¹ Meanwhile, atoms are also repelled by the electron-electron and nucleus-nucleus interactions. Thus, the atomic spacing ( $a_{0}$ ), referred to as the equilibrium position, is determined when the attractive and repulsive forces cancel each other. During elastic deformation at a small strain, causing a displacement δ, the combined effect of attraction and repulsion causes the atomic bonds to act as a spring with an atomic spring constant, S. Modelling the system as a spring, the macroscopic elastic modulus of a material (E) can therefore be estimated by the ratio E = S/ $a_{0}$ (Figure 3A).³¹

Figure 3.

Scientific background on Youngs Modulus and relationship between vibrational frequency of a tuning and its materials properties. (A) Spring model for atomic bonding, where representations of the forces and energy, U, on two atoms are being displaced from one another by an applied force, F. The atomic spring stiffness, S, is highlighted as the slope of the force versus displacement, δ, curve. Taking the spring model into account and making an analogy to the spring constant equation, the equivalent of the spring constant S becomes Young's modulus, E, or the material's elastic modulus, which can then be related to stress and strain. (B) Similar to a spring, a material will exhibit a certain vibrational frequency, illustrated herein, which depends on the compressibility of the inter-atomic bonds or E. (C) Depiction of how vibrational frequency for the tuning forks used in this laboratory relates to Young's Modulus and the density of a material through the fundamentals of wave propagation through a material. Figure 3A adapted from Ashby et al.³¹

If a force is applied to the atomic spring system, the atomic spring constant S is representative of the stiffness of the bonds and relates to the material property of Young's Modulus, E, or the modulus of elasticity.³¹ Discussed with the learners, like a spring, if too much force is added, an analogy can be made that permanent “kinks” are introduced, where, beyond the elastic regime, bonds in the atomic “spring” system are stressed to a point at which plastic deformation occurs with irreversible damage.

Considering mechanical deformation in a solid, for example, elastic vibrations or crack propagation often travel in the form of an elastic stress wave – like a pressure wave passing through a spring (Figure 3B). How this elastic stress wave travels within the material depends on the compressibility of the inter-atomic bonds. Thus, in isotropic solids, the speed of longitudinal elastic wave propagation (i.e., the speed of sound, v) is governed by Young's Modulus E and the material density ρ,^31,32 as shown in Equation 1 (Figure 3C):

v = \sqrt{E / ρ}

(1)

For a slender rod of constant length L and cross-sectional area A, the elastic wave propagation time determines the rod's natural frequency of vibration ƒ. This frequency is dependent on the geometry and material:³¹

f α \frac{1}{L^{2}} \sqrt{\frac{E A}{ρ}}

(2)

This relationship explains why materials with higher stiffness (greater E) and lower density ρ transmit stress waves more rapidly and vibrate at higher frequencies.

Burleigh and Fuierer utilized knowledge of this relationship to quiz learners about the material properties of tuning forks throughout their ‘vibrant’ teaching.³³ Laughlin et al.³⁴ measured the quantitative acoustic properties of materials and compared those of musicians. They utilized 2 John Walker 440 Hz steel tuning forks of equal dimension but coated with different surface treatments. One of the forks had an iron oxide coating produced by a bluing process, and the other was gold-plated. Moreover, the researchers commissioned the creation of tuning forks of the same dimensions but made of a variety of different materials: uncoated mild steel, stainless steel, zinc, copper, brass, solder, lead, nylon, acrylic, glass (with cylindrical tines), spruce, walnut, obeche, ironwood, bass, plywood and balsa wood. The researchers then utilized a microphone to capture data, which was fed directly into a computer's sound card, they manipulated the tuning forks by pinching the fork's tines together. Through this, the three principal factors influencing the production of the sound of a tuning fork were summarized as the shape of the fork, the mass density ρ and the elastic modulus E.

In the tuning fork considered herein, this vibrational frequency can be approximated to that of a cantilever beam with one fixed end,³⁵ as follows:

f = \frac{{1.9}^{2}}{2 π L^{2}} \sqrt{\frac{E I}{ρ A}}

(3)

As it applies to the tuning fork, learners will understand the Eq. 1 relates to the material properties, whereas the additional term in Eq. 3 relates to the geometric properties of a tuning fork. Thus, the selected materials for the tuning fork have a proportional and significant impact on the frequency observed.

For this laboratory application, it is important to note that several assumptions are being made, each with associated limitations in interpretation. The key assumption is that the activity uses a cantilever beam model based on the classical Euler-Bernoulli beam theory, which relates flexural stiffness and geometry to natural frequency. In this case, it is assumed that there are small deflections, that the materials follow linearly elastic behaviour, and that the beam is slender, such that plane sections remain in plane and perpendicular to the neutral axis. Under these assumptions, shear deformation is assumed to be negligible in the kinematic model, although shear stresses exist to satisfy internal force equilibrium. The approach is deemed appropriate for the thin ruler specimens and tuning forks used in activities, where length-to-thickness ratios are large, and bending is the dominant deformation mechanism. Limitations include sensitivity to boundary conditions (clamping), damping effects, and geometric tolerances, all of which may introduce deviations from the idealized prediction. These considerations provide an opportunity for learners to discuss modelling assumptions and the relationship between theory and experimental observation in the laboratory.

Laboratory activities: Methods & materials

Educational approaches

As introduced in Figure 2, the newly designed laboratory is split into three phases covering the: (A) Importance for learning, (B) Learning the Science: Material Oscillation & Young's Modulus, and (C) Theory Applied & Validated. Parts (A) and (B) were highlighted in the previous subsection and discussed collaboratively with learners, whereby interactive components using active learning strategies were incorporated (having learners engage in the lesson material and reflect on what they are learning). This aids in contextualizing the importance of the activities by reflecting on everyday applications. Then, we briefly explain how it all works in a simple way that is suitable for a laboratory. Herein, we will discuss the key laboratory activities which involve the learners directly in applications related to music and other mechanically relevant things in their lives.

The main laboratory activities relevant to exploring oscillatory concepts in mechanical design for musical applications are split into two components: 1) Ruler Oscillation Demonstration and 2) Tuning Fork Exercise. These two activities are described in the following subsections. The learning objective of these two demonstrations is to familiarize learners with the concepts of oscillation and the mechanical properties of materials. When teaching students about oscillations and the material properties that affect oscillation in an environment which is easier to approach, educators can then extend this knowledge to more complex topics. While the behaviour of the ruler oscillators and tuning forks can be described using classical beam theory, the activity is intentionally framed as a conceptual and experiential learning tool, rather than a formal quantitative validation of beam theory.

In implementing these activities, we relied on an experiential learning approach involving hands-on, active learning elements where learners are challenged about their knowledge and reflecting throughout the activities (Figure 1). The key to experiential learning is reflecting on the experience and contextualization through abstract conceptualization (Figure 1), where learners can contextualize the experience in their engineering education.^17,18

The focus on reflection throughout activities could be supported by Active Learning as described by Millis,¹⁴ thus, experiential learning strategies and activities would benefit from active learning strategy implementation. Carvalho further mentions that experiential and active learning go together in successfully designing and implementing experiential activities.¹²

Oscillation demonstration of rulers made of different materials

The first hands-on activity within this laboratory was the Ruler Oscillation Demonstration, which compares the resonance frequencies of rulers made of various materials, notably 316 stainless steel, aluminum 6061, and an acrylic polymer. In designing this activity, we wanted to focus on using accessible, readily available materials so that the laboratory could be easily adapted. Using rulers as our cantilever beams in this activity makes the exercise more accessible, provided many academic environments have them. It further engages learners by teaching materials science with an everyday school item – thinking about the quotidian ruler in a new, foreign way. This method was adapted with permission from science communicator and author Steve Mould, specifically inspired by his YouTube video titled,²⁶ “How a quartz watch works - its heart beats 32,768 times a second.”

The activity illustrates the dependence of resonance frequency on Young's Modulus E and density ρ. An “Oscillator” setup was produced using t = 5.5 mm thick acrylic (Figure 4, dimensions provided in the supplement). Additionally, long rectangular metal strips were laser cut to act as rulers or otherwise purchased, where standard 30 cm / 12-in rulers were considered. These strips are composed of different metals with different thicknesses, providing a variety of samples to oscillate. Each strip would have a different behaviour, as Young's Modulus E, density ρ and thickness t all impact the oscillation frequency. A 3D computer-aided design (CAD) model was created to design and dimension the custom oscillator assembly (Figure 4, dimensions provided in the supplemental materials, Figure S1–S5).

Figure 4.

Simplified diagram of custom oscillator assembly. (A) The front isometric view highlights how a material strip ruler is fastened to the stand for assembly, showing the oscillatory motion of the ruler's back-and-forth directions within double-ended arrows. (B) The rear isometric view of the holder highlights the electromagnet and floating wire used accordingly. CAD drawings are provided within the supplemental material of this work detailing the dimensions of all components.

To demonstrate the relationship between material properties and the oscillation frequency, we adopted a new oscillation demonstration inspired by Steve Mould's content.²⁶ The setup consists of a plastic ruler (acting as a cantilever) and an electromagnet, which initiates and sustains mechanical oscillations. The apparatus highlights how stiffness and mass affect and illustrates the fundamental principles of harmonic motion.

The ruler becomes displaced from its own equilibrium position and released; the ruler has oscillatory motion due to the restoring force of its own elasticity. As in any damped harmonic system, the amplitude of oscillation gradually decreased over time until mechanical energy is reintroduced via an electromagnet-controlled pin.

The demonstration relies on an intermittent triggering circuit, which consists of a strip of copper tape affixed to one edge of the ruler, which contacts a floating wire positioned nearby. The ruler will only contact the wire at the ruler's maximum displacement. The contact briefly closes the circuit, allowing current to flow from the 9 V battery and causing the pin to strike the ruler. The force imposed by the pin sustains the ruler's motion and maintains a continuous oscillation (Figure 4), further exemplified in the video inspiring this activity by Steve Mould.²⁶ The apparatus allows for a qualitative comparison of vibration frequency across rulers made of different materials or dimensions. The oscillation frequency is influenced by the material's Young's modulus (E), density (ρ), and the ruler's length and thickness; thus, rulers made of different materials and designs would have different oscillation frequencies. However, readers should note that the maximum oscillation frequency that can be accurately observed in this demonstration is limited by the response time of the electromagnet. Therefore, if the ruler oscillates too rapidly, the electromagnet may fail to actuate in time to sustain motion.

Multi-material tuning fork exercise: Demonstrating the connection between material selection and harmonics

Following the previous activity, learners further develop their understanding of how material properties affect oscillation by exploring how material selection impacts tuning fork pitch. For interactive demonstration purposes, five tuning forks were custom-made from 0.25″ thick and 1.5″ width flat bars using the following materials to the dimensions specified in Figure 5A: 1) Stainless steel (SS316), 2) Brass (360), 3) Aluminum (AA6061-O), 4) Aluminum (AA6061-T6), & 5) Plastic (Delrin^®, also known as polyoxymethylene). Work produced by Burleigh and Fuierer (2005) on using, “Tuning Forks for Vibrant Teaching” inspired this exercise and was adapted within this laboratory.³³

Figure 5.

Tuning fork materials, dimensions, and influence of material selection on pitch. (A) Geometrically identical tuning forks made of five different materials as follows: Brass (360), Stainless steel (SS316), Plastic (Delrin^® Acetal, otherwise known as polyoxymethylene), and aluminum (AA6061-T6 alloys and AA6061-O). (B) Associated design specifications of tuning forks used in this work. (C) Material selection Ashby plot highlighting Young's Modulus (GPa) versus Density (kg/m³). The plot was created using ANSYS-Granta EduPack, where callouts highlight tuning fork materials on the graph.

Since the students learned how vibrational frequency can be useful in creating devices such as a crystal oscillator at the start of the laboratory, the next part of demonstrating material properties is to delve into the physics behind vibrational frequency. The theory being instructed here is how vibrational frequency relates to material oscillation and how people hear those oscillations as different pitches. Students approach this topic with the foundational knowledge of sound waves. The material selection aspect comes into how Young's Modulus relates to vibrational stress waves, as previously introduced in Eq. 1. We noted in the educational background that for a rod with a constant length L, there would be a well-defined time required for the stress wave to propagate from one end to the other. As a result, when we hit a rod, it tends to vibrate at its natural frequency f, represented for a tuning fork in Eq. (2). Learners are asked about the equation, and if they note any trends, and if a learner does not guess it, educational staff highlight that the only material property terms in Eq. 2 is $\sqrt{E / ρ}$ .

The instructor would continue the demonstration by posing this question to the students, “I will demonstrate hitting a set of tuning forks made of different materials (aluminum, copper, steel, plastic) but with the same geometry. Can you guess which material will give the highest pitch? Which material will give the lowest pitch?” Learners often guessed the steel sample to have the highest pitch, recognizing it as one of the heavier materials. Further, learners would be explained the difference between the two aluminum tuning forks, one being tempered (AA6061-T6) and stronger, while the other being annealed (AA6061-O). They would be asked, “Which of the two aluminum alloys will have the highest pitch?” Being an introductory materials science course, this somewhat puzzled learners, being less intuitive for them to think on; some had noted that they thought the stronger aluminum alloy would have a higher pitch.

The laboratory continues with the pitch measurement of each of the tuning forks. However, upon recording the pitch of each material, the aluminum and steel samples would have been found to have just about the same pitch – going against the grain of the commonly guessed answer. It is noted in the laboratory that a cell phone with a free pitch-recording application was used to record, as an accessible and inexpensive means of demonstrating this concept. It is recommended that laboratory instructors test measurement accuracy in advance in the room where the demonstration will take place to ensure that the recorded pitch is sufficiently accurate. Further, additional noise in the room can lead to measurement error, and it is recommended that learners be asked to be quiet while measuring the tuning fork pitch.

By connecting Young's modulus and density (Figure 5C), we show students that a higher $\sqrt{E / ρ}$ value yields a higher pitch. Plotting $\sqrt{E / ρ}$ for the materials, students observe that aluminum and steel fall on the same line (Figure 5C) and therefore produce the same pitch. Since Young's modulus and density are unaffected by heat treatment, tuning forks of the same size will have identical pitches regardless of processing history.

To reinforce this concept and introduce professional tools, we used Ansys Granta EduPack (Ansys, Inc., PA, USA) to generate Ashby plots comparing Young's modulus and density. These visualizations helped students link the theoretical E/ρ–pitch relationship to their experimental results while gaining experience with an industry-standard material selection tool. The software served two key roles: (1) making atomic-level properties like density and stiffness more tangible, and (2) teaching students how to navigate and interpret material property charts. By graphically plotting $\sqrt{E / ρ}$ , we contextualized how processing routes (e.g., cold working) affect mechanical properties, creating a foundation for later lab activities. Students then consolidate their understanding through a follow-up assignment applying these principles to a coated sample scenario (Supplemental Figure S6), encouraging knowledge transfer to new contexts.

Discussion on practical implications, objectives, and lessons learned

Engineers must problem-solve, innovate, and create novel solutions. Educating learners on the essential aspects of critical thinking and how to apply the scientific method to draw conclusions may be more impactful than traditional memorization of theoretical knowledge.

To expand on how material properties are traditionally taught, this work presents interactive, low-cost and non-destructive laboratory activities that utilize oscillating rulers in a cantilever beam setup and tuning forks as harmonic oscillators to teach first-year engineering learners about mechanical and material properties, specifically Young's modulus E. These activities complement lecture content by giving learners intuitive, hands-on ways to engage with material concepts. Exploring the foundations behind how a tuning fork works through these new activities creates a valuable intersection between theory and practice, encouraging learners to use critical thinking to draw scientific conclusions.

From these baseline concepts, educators introduce how oscillator clocks work, which is a cornerstone of many technologies. This provides students with a development timeline from core concepts to advanced applications. From here, understanding high-frequency tools, atomic force microscopes, and other technologies becomes easier as students grasp how these technologies work. By linking oscillatory behaviour to mechanical properties, learners explore how stiffness influences natural frequency and pitch, connecting classroom theory to both everyday phenomena and different instruments, such as a quartz clock and atomic force microscopy.

To educate learners on how to select materials and understand their properties, this framework offers numerous opportunities. For instance, educators can use these labs to teach how acoustic velocity and mechanical loss coefficient relate to material damping, how geometry influences mechanical response, and how processing (e.g., cold work) affects properties. By grounding lectures in real-world case studies, this approach motivates students to engage deeply with both the breadth and depth of engineering subject matter while developing confidence in solving realistic problems.

As part of a McMaster Research Ethics Board-approved survey (MREB #5540), with survey results and methods published in the article by Earle et al.,³⁶ students enrolled in the E1P13 course were asked to evaluate the four laboratory activities completed throughout the semester where this activity was implemented. Over 35% of respondents identified the “Principles of Mechanical Structures” laboratory, which implemented these activities, as their favourite. The most frequently cited reasons included that the lab was fun, interactive, held their attention, and introduced new engineering concepts. These findings suggest that such activities not only engage students but may also enhance conceptual learning through active participation.

The pedagogical approach demonstrated in this work is grounded in a body of literature supporting active, hands-on learning throughout engineering education. Freeman et al. demonstrated across undergraduate STEM that active learning consistently improves examination performance and reduces failure rates.⁷ Within mechanical education specifically, hands-on activities designed as lecture supplements improve engagement and conceptual understanding even in large courses.³⁷ The design of these activities is further supported by evidence that inquiry-based laboratory experiences, rather than traditional-style laboratories, improve student engagement, attitudes toward experimentation, and critical thinking skills without negatively impacting overall understanding or exam performance.^38,39 These works collectively reflect a broader pedagogical shift toward accessible, experiential learning as a means of reinforcing concepts, a priority particularly for large first-year engineering cohorts where hands-on opportunities are often constrained by available infrastructure.

Based on this preliminary success, the implementation of the Kolb experiential learning cycle is also further attributed as a contributing factor to the success of these activities, which has been shown to reinforce conceptual understanding through iterative reflection, active experimentation, and problem-solving.^17,18 Structuring laboratory activities around this framework, combined with hands-on experimentation, enables learners to progress from a purely theoretical grasp of concepts to a deeper, applied understanding. This discovery-based approach not only consolidates learning but also cultivates the critical thinking and technical skills required to address complex laboratory challenges. Such evidence-based pedagogical strategies present a promising model for designing future educational interventions.

Thus, by utilizing hands-on and engaging learning methods, we have developed a set of interactive, materials-science-centered activities for first-year engineering students that promote both student engagement and experiential, transformative learning. This project represents a shift toward designing lecture content grounded in real-world design challenges, supported by tools such as Ansys Granta EduPack to visualize material properties and reinforce theoretical concepts.

Future iterations can expand on this work by creating design-led case studies that not only provide learners with foundational scientific knowledge but also encourage them to apply creativity and critical thinking to solve realistic engineering problems across disciplines. Additionally, assessing learning outcomes systematically can guide continuous improvement. By incorporating these innovative laboratory experiences, educators have the opportunity to integrate interdisciplinary concepts into their courses, enriching and diversifying the engineering curriculum. As teaching methods continue to evolve, it is essential that strategies for materials selection and mechanical design education advance in parallel, ensuring that learners are equipped with the tools, confidence, and mindset required to meet the complex challenges of future engineering practice.

Summary

Effectively teaching the fundamentals of material properties is essential in early engineering curricula to ensure retention and understanding of content. Within this work, we have highlighted new affordable and non-destructive ways to teach learners through hands-on activities about mechanical and materials properties of materials. Notably, this work focuses on connecting tuning fork and oscillatory science with novel approaches to teach learners about the foundational importance of Young's Modulus. Taking an active approach to experiential learning methods by implementing course elements, as illustrated in this work, particularly in the first-year fundamental learning experience, can improve student learning enjoyment and engagement. Implementing these innovative labs highlights the broad opportunities educators have to use interdisciplinary topics to teach course-based content, complimentary to current curricula. With evolving pedagogies, materials selection in mechanical design should not be left behind, and educators in the field must think about how to adapt and improve traditional materials selection in teaching and learning for the next generation of learners.

Supplemental Material

sj-docx-1-ijj-10.1177_03064190261446963 - Supplemental material for Introducing mechanical and material properties to first-year engineering learners through intuitive physical demonstrations involving oscillators and tuning forks

Supplemental material, sj-docx-1-ijj-10.1177_03064190261446963 for Introducing mechanical and material properties to first-year engineering learners through intuitive physical demonstrations involving oscillators and tuning forks by Liza-Anastasia DiCecco, Johnathan Spinelli, Mymoon Bhuiyan, Shayna Earle, Dakota M. Binkley and Bosco Yu in International Journal of Mechanical Engineering Education

Footnotes

ORCID iDs

Liza-Anastasia DiCecco

Bosco Yu

Ethical considerations

Ethical approval of the survey evaluating this work³⁶ referenced in the discussion was obtained from the McMaster Research Ethics Board (MREB #5630).

Consent for publication

Not applicable.

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Financial support provided through the McMaster Faculty of Engineering as well as McMaster MacPherson Institute programs, specifically the Student Partnership Program (SPP) and Priority Areas for Learning and Teaching Research (PALET) Grant are greatly acknowledged. Additionally, special thanks to Steve Mould²⁶ for his support in this work and help inspiring us to design this laboratory activity. Finally, Lakshana Mohee from Ansys, Inc, is thanked for all her support with using the Ansys EduPack software as well as continuous encouragement.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data availability

All relevant data regarding the design and implementation of the activities described in this article are shared within this manuscript and the supplemental.

Supplemental material

Supplemental material for this article is available online.

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