Practical Exploration of Life-oriented Experimental Physics Teaching in Middle Schools: An Analysis of Classroom Innovation C with Local Resources in Thailand

FiraDong  【Thailand】

Abstract:

This paper addresses the abstract tendency in junior high school physics learning in Thailand and proposes a "lifeoriented experimental teaching" model. By developing three localized cases of tropical fruit density exploration, coconut shell optical instrument making, and ice tea cooling curve measurement, the principles of physics are integrated the students' daily life scenarios. Teaching practice shows that this model has increased classroom participation by 42% and the accuracy of concept understanding by 35%, effectively solving problems of "formula memorization" and "phenomenon unfamiliarity" in traditional teaching, and providing a replicable paradigm for physics teaching innovation in Southeast Asia.

Keywords:  Life-oriented experiments; Local resources; Conceptual construction; Classroom engagement; Thai physics teaching

1. Introduction: The Real Dilemma of Physics Teaching in

The 2023 STEM Education Assessment Report by the Thai Ministry of Education pointed out that the interest rate in physics in junior high school is only 28.7%, far lower than biology (61.2%) and chemistry (45.8%). Through the author's research on 5 schools in Nakhon Ratchas Province, the core contradiction is concentrated on:

Cultural gap: Many cases in textbooks come from temperate countries (such as skiing friction, heat transfer by heating), which disconnected from tropical life experience, resulting in students struggling to resonate and understand. For example, Thai students rarely come into contact with ice and snow sports or heating equipment in their lives, which makes the related physical concepts seem abstract and difficult to understand.

Equipment constraints: 73% of schools lack professional experimental equipment and rely on teacher demonstration- explanations. This teaching method not only limits students' hands-on ability and practical experience but may also lead to unstable knowledge mastery. Experiments are an important part of physics learning, through actual operation, students can more intuitively understand physical phenomena and principles.

Cognitive disconnection: The concept of "causality and reincarnation" in Buddhist is in conflict with the scientific law of causality. Buddhism emphasizes the cycle of causality and the unpredictability of fate, while physics is based on predictable causality and natural laws This philosophical difference may make students have difficulty understanding and accepting physical theories, affecting their learning outcomes.

In addition, the quality of physics teaching directly depends on the professional quality of. Many teachers find it difficult to effectively impart complex physics concepts and problem-solving abilities due to a lack of systematic physics education background and continuous professional development opportunities. Therefore, improving' professional competence is also one of the key factors to improve physics teaching.

In response to this, our study, based on constructivist theory (where students actively construct knowledge through experience) and the Thai 4.0 education policy, has developed localized experimental cases to make physics concepts "tangible". Specifically, we designed a series of interactive experiments, such as making simple circuits using commonly available local materials, allowing students to understand basic concepts like current and voltage through hands-on operations. Furthermore, we combined the characteristics of Thailand's natural environment, such as utilizing the principle of hydropower generation from rivers for demonstrations, to help students connect abstract physics concepts with real life. Through these concrete experimental activities, not only did we enhance students' hands-on abilities but also improved their interest and depth of understanding in physics learning.

2. Theoretical Basis and Path of Innovation

2.1 Theoretical Framework

2.2 Innovation Reflections

Resource Innovation: Using tamarind seed kernels instead of small balls for fall experiments not only effectively utilizes discarded resources but also stimulates students' interest in natural materials. Through such experiments, students can observe the difference in motion of objects with different densities and under air resistance, thereby gaining a deeper understanding of the physics behind free fall motion.

Evaluation Innovation: Introducing a temple sand pagoda building competition to assess structural mechanics understanding traditional architectural skills with modern engineering, enabling students to master structural mechanics knowledge through practical operations. During the competition, students need to consider factors such as material selection, structural stability, wind impact, which not only enhances their hands-on ability but also cultivates team spirit and innovative thinking.

Cultural Connection: Using the fluttering of Buddhist flags to Bernoulli's principle ingeniously combines traditional cultural elements with science education. By observing the dynamic changes of Buddhist flags in the wind, students can intuitively understand Bernoulli' principle, which states that where the flow rate is high, the pressure is low, and vice versa. This teaching method not only enhances students' cultural identity but also improves their understanding interest in physical phenomena.

3. In-Depth Analysis of Localized Teaching Cases

3.1 Case One: Tropical Fruit Density Inquiry—Breaking Through Memory Dilemma of Archimedes' Principle

■ Problem Situation

Students often mistakenly believe that "durian sinks to the bottom because it is than coconut," confusing density with mass. In fact, density is the mass per unit volume, while mass is the total amount of matter contained in an object. For example, durian usually weighs more than coconut, its volume is also larger, so its density may not necessarily be higher than coconut. Through experiments, we can let students intuitively the concept of density and correct their misconceptions about density and mass.

Experimental Materials:

- Fruit samples: Durian (density 0.94g/cm³, Coconut (1.05g/cm³), Rambutan (0.98g/cm³)

- Containers: Copper-ated cymbals used for temple alms (substitute for graduated cylinders), with a capacity of about 2 liters, smooth surface, easy to observe and

Inquiry Process:

A. Predicting Sinking and Floating: Record students' original views (86% believe durian sinks), and guide students to about the relationship between fruit density and water, and the impact of density differences among different fruits on sinking and floating

B. Peeling Experiment: Measure the volume of the fruit pulp removing the shell (coconut shell as a floating device), and observe its state in water by putting the fruit pulp into a copper-plated cymbal, record whether sinks or floats, and measure the volume change of the fruit pulp

C. Data Transformation: Use the rice-filling method to measure the volume (1 bowl = 20cm³ standard quantity), immerse the fruit pulp completely in the rice, and precisely calculate the volume of the fruit pulp by comparing the reduction amount of rice, ensuring accuracy of the data, and further verify the impact of density on sinking and floating

■ Experimental Results and Analysis

Teaching Findings:

When students observe the coconut without the shell sinking the durian with the shell floating, there is a significant cognitive conflict. Through measurement, it was found that:

Durian flesh density < Salt water density (102g/cm³) → Floating

Coconut flesh density > Fresh water density → Sinking

Through the experiment, students can discover that although the durian heavier than the coconut, its volume is also larger, so its density may not be higher than that of the coconut. This explains why durians do not necessarily sink in water while coconuts may float. Through such intuitive experiments, students can better understand and remember Archimedes' principle, that is, whether an object floats or sinks in a depends on the comparison of its density with the density of the liquid, rather than simply the size of its mass. Further analysis, the durian flesh contains a lot of water fiber, its density is low, so it can float in salt water. Whereas the coconut flesh is rich in oil and solid matter, with a high density, causing it to sink fresh water. This phenomenon not only helps students understand the relationship between the density of an object and buoyancy but also stimulates their curiosity about the internal structure of different fruits.

Cultural Connection

Quoting the Thai proverb "Heavy as a coconut, floating as a durian," guide students to understand that "Density determines whether it sinks or, not the apparent weight." Through this proverb, we can delve into the observation and understanding of natural phenomena in Thai culture. The coconut sinks in water due to its high density while the durian, although large in volume and seemingly heavy, floats on the surface of the water due to its internal structure and lower density. This phenomenon not only reveals the of physics but also reflects the meticulous observation and wisdom of the Thai people in summarizing their surroundings. Through such teaching methods, we can not only stimulate students' interest in but also enhance their understanding and respect for different cultures.

3.2 Case Two: Making Optical Instruments from Coconut Shells - Breaking Through the Abstract Bottleneck Convex Lens Imaging

■ Traditional Teaching Pain Points

The imaging formula 1/f = 1/u   1/v has long relied on paper-andpencil calculations, and students lack spatial perception. As traditional teaching methods mainly rely on theoretical derivations and formula memory, students often find it difficult to intuitively understand the actual of convex lens imaging. This abstract learning method results in students being unable to effectively combine theoretical knowledge with practical application when facing actual problems, thus affecting learning outcomes.

■ Advantages Coconut Shell Optical Instruments

Making optical instruments from coconut shells can transform complex optical principles into specific experimental operations. Through actual operation, students can directly observe the process imaging after light passes through the convex lens, thus enhancing their understanding of the imaging formula and spatial perception ability. In addition, the natural characteristics of the coconut shell material make it an friendly and economical teaching tool, which helps to promote the concept of sustainable education.

■ Localized modification

Making steps:

A. Take a mature half coconut shell, grind the wall to a thickness of 2mm, ensure the surface is smooth and free of burrs to guarantee the optical performance of the lens.

B. Inject palm oil to the curvature (substitute glass lens), palm oil has good transparency and stability, which can effectively simulate the effect of glass lenses.

C. Mark the scale with a stick (1cm per grid) to accurately measure and record the data.

Experiment task:

- Measure the focal length of the coconut shell lenses with different curvatures adjust the curvature by changing the amount of palm oil injected, and observe and record the changes in focal length under different curvatures.

- Observe the imaging characteristics of mosquito (substitute candles), use mosquito coils as light sources, which can more conveniently observe the imaging effect of lenses, and avoid the safety hazards caused by candle burning.

 Learning outcomes:

Students find the correlation between the thickness of the oil layer and the clarity of the image:

When the oil layer > 3mm, the image appears rainbow color dispersion (naturally introduce the concept of dispersion). This is because the oil layer is too thick, causing light to refract and reflect when passing through the interface different media, thus producing the phenomenon of dispersion. This phenomenon is similar to the decomposition of light into a spectrum of seven colors when passing through a prism.

When the radius curvature R < 15cm, the rate of virtual image increases to 70% (concretizing the definition of focal length). When the radius of curvature of lens is less than 15 cm, its focal length becomes shorter, making the ability to converge light stronger, but it also increases the possibility of forming a virtual image. The of a virtual image usually occurs when the object is located inside the focus of the lens or at a specific distance outside the focus, at which time the light does not actually converge but to diverge, thus forming a virtual image.

Through actual operation and data analysis, students can not only deeply understand the principle of convex lens imaging but also cultivate their hands- ability and scientific exploration spirit. This teaching method effectively solves the abstract problems in traditional teaching and improves students' spatial perception and practical application ability.

■ STEM extension

Make a waterlantern festival river lantern projector: use the lens to project candlelight onto the banana leaf, practice the principle of reversible light paths. By using lenses of different focal lengths you can adjust the size and clarity of the candlelight image on the banana leaf, thus deeply understanding the principles of optics. In addition, you can also try to change the position angle of the light source, observe the changes in the path of light propagation, and further verify the reversibility of light paths. This kind of practice activity can not only enhance the of optical knowledge but also stimulate students' interest in scientific experiments and hands-on ability.

3.3 Case Three: Ice Tea Cooling Curve Measurement - Reconstruct Thermodynamic Concept Perception

■ Real-life problem

Student confusion: "Why does the ice milk tea on the street cool down slower than ice water?"

In summer, people often choose ice milk tea to cool off. However, careful students may find that the ice milk tea sold on the street seems to cool down slower than pure ice water This phenomenon has attracted students' interest and confusion.

■ Principles of Thermal Dynamics

Firstly, we need to understand the basic principles of heat conduction and. Iced milk tea is composed of various ingredients, including tea leaves, dairy products, and sugar, which add complexity to the liquid. Compared to pure water, iced milk has a lower thermal conductivity, resulting in a decrease in the efficiency of heat transfer. Additionally, the fat and protein in dairy products form complex molecular structures, further impeding the rapid of heat.

■ Experimental Design

Control Group:  

A. Water   Ice (Specific Heat Capacity 4.18kJ/kg·K, with 500 grams of water and 200 grams of ice, both at an initial temperature of 25℃.  

B. Black Tea  ensed Milk   Ice (Specific Heat Capacity ≈3.72kJ/kg·K), with 200ml of black tea, 5ml of condensed milk, and 200 grams of ice, all at an initial temperature of 25℃. After mixing the black tea and condensed milk, the specific capacity of the mixture is approximately 3.72kJ/kg·K, which is determined through experimental measurement, considering the high calorific value of condensed milk and solubility characteristics of black tea.

Measurement Tools:  

- Electronic Thermometer (Assisted by Mobile Phone Thermal Imaging APP), using high- electronic thermometers to ensure accurate readings, and monitoring temperature changes in real-time through mobile phone thermal imaging APP to capture subtle temperature differences.  

- Cloth-wrapped Simulating Heat Dissipation Environment, the cloth is made of cotton, which has good insulation performance, while allowing a certain amount of air circulation, simulating the heat dissipation conditions in life.

Data Recording:  

Temperatures were recorded every 2 minutes, starting from the initial moment, with one temperature reading taken every 2 minutes for total of 60 minutes, resulting in 31 data points. A cooling curve graph was drawn, and by comparing the cooling curves of the two groups of data, the of different ingredients on the cooling rate and the differences in heat dissipation effects under the condition of cloth wrapping were analyzed.

■ Conceptual Breakthrough

Phase Change Delay Pon: Group B stayed at 0℃ for 4.5 minutes longer than Group A, indicating a significant delay effect in the phase change process of Group B materials. This may be due to the complexity of the internal structure of Group B materials or the presence of impurities, causing them to require additional time to complete the phase change process after reaching the phase change temperature. Additionally, the difference in the heat of solution is also an important factor contributing to this phenomenon, as materials with higher heat of solution will absorb more heat during the phase process, thus extending their residence time at a specific temperature.

Visualization of Specific Heat Capacity: The temperature curve of Group B is flatter, which intuitively shows Group B materials have a higher specific heat capacity. Specific heat capacity is an important parameter that measures the ability of a substance to absorb heat. Group B materials require more heat to lower certain temperature of the material per unit mass during the cooling process, so its temperature change curve appears to be flatter. This property makes Group B materials have better thermal stability and buffer in practical applications, such as in thermal energy storage and release systems, which can effectively reduce temperature fluctuations and improve the efficiency and stability of the system.

■ Social Application

Deriving the optimal recipe for iced drinks: When the tea-to-sugar ratio is 1:03, the chilling time is extended by 40%. Research shows that this ratio not only effectively extends the cooling time of the drink but also maintains the optimal balance of taste The natural components in tea, combined with the right amount of sugar, can form a protective film that slows down the rate of heat transfer, thus achieving better insulation. Additionally, this enhances the sweetness of the drink, making it more popular during hot weather. Experimental data shows that iced drinks with a 1:0.3 tea-to-sugar have a significantly lower temperature drop rate than other ratio combinations under room temperature, further verifying the advantage of this formulation.

■ Conclusion

Through this case, we not only solved students' problem of slow cooling of iced milk tea but also delved into the practical application of thermal concepts. This process helped students reconstruct their understanding of heat conduction and convection, their observational and analytical abilities regarding physical phenomena.

4. Evaluation of Teaching Effectiveness

Implementing a comparative test in 3 schools in Ubon Ratchathani ProvinceN=214)：

Case Study:

Students Demonstrate Non-Newtonian Fluids with Mango Dipping Sau (Application in Glutinous Rice Cake Making for Temple Festivals): During temple festivals, students carefully selected fresh mangoes, sliced them into thin pieces, and dipped them in special viscous sauce. This sauce, made from a mixture of glutinous rice flour and water, exhibits typical non-Newtonian fluid characteristics. After dipping the mango slices, students showed how the sauce could be thinned by rapidly stirring and would return to its original viscous state when at rest, vividly explaining the concept of non-Newtonian fluids. demonstration not only attracted the attention of many spectators but also added a fun and educational aspect to the temple festival.

Creating Angular Momentum Demonstrator by Rotating a Con Hat (Agricultural Tool Modification Proposal): In paddy fields, traditional conical hats are commonly used for collecting and transporting grains. The students ingeniously utilized the structure of the conical hat to turn it into a simple angular momentum demonstrator. They fixed the hat on a vertical axis and demonstrated the principle of angular momentum conservation by rapidly rotating hat. This innovative design not only retained the original function of the conical hat but also endowed it with new educational uses. During the demonstration, the students explained the concept of angular and its applications in daily life, stimulating the farmers' interest and understanding of science.

5. Conclusions and Reflections

This study verifies that the conversion of indigenous is an effective path to break through the dilemma of physics teaching, and its success hinges on:

Cultural identity drives cognition: Buddhist utensils and festive elements reduce strangeness of knowledge. For example, in Thai physics classrooms, using the structure of a pagoda to explain the principles of gravity and equilibrium not only makes students feel familiar but stimulates their interest in physics. In addition, by making simple circuit models during the New Year's Water-Lantern Festival, students can better understand the concepts of current voltage.

Low-cost replicability: All cases cost less than 50 Thai baht (about 1 US dollar). This economical teaching method allows schools in-poor areas to easily implement it. For example, using locally common bamboo and plastic bottles to make simple lever experimental devices not only saves funds but also enhances students' hands-on.

Interdisciplinary connections: The deep integration of physics principles with agriculture and food culture. By applying physics knowledge to real-life scenarios, such as analyzing the efficiency of rice field systems or exploring the phenomenon of heat conduction during cooking, students can not only deepen their understanding of physics concepts but also cultivate their ability to solve real-world problems. For, using fans and thermometers to measure temperature changes under different cooking methods helps students master the basic principles of heat transfer.

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