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The cosine theorem is used in solving triangulation problems and in physics when solving problems of addition of unidirectional oscillations. However, this theorem is used only for the analytical calculation of triangles or when solving problems of adding two oscillations. Here we propose a generalization of the cosine theorem for the case of calculating polygons of arbitrary shape and consider its application for calculating the results of adding an arbitrary number of unidirectional oscillations or coherent waves with an arbitrary phase distribution.

The article presents the results of four series of experimental studies of irradiation efficiency of Moskovskii Parnikovyi leaf lettuce with general and special-purpose LED lamps (phyto-lamps) under various irradiation modes. The studies were conducted with an automated experimental irradiation device. The influence of the spectral compositions of LED radiation on the growth and development of Moskovskii Parnikovyi leaf lettuce is estimated. The studies have shown that LED phyto lamps are more effective in terms of productivity of Moskovskii Parnikovyi leaf lettuce compared to general-purpose LED lamps with equal electrical power consumption.

This paper explores what place means for early childhood education at a time of global environmental precarity. We draw on fieldwork in Arctic Norway, where kindergarten children spend time with snow for more than half of the year. Children's movement attunes to the nuances and diversity of the snow, as seasons, temperature, light, wind and weather change the consistency of snow and the possibilities for what can occur. The paper presents data of children walking in deep snow during an ice-fishing trip, a practice known as 'grynne', asking what we can learn both about the moment-by-moment attunement between child, snow and place necessary to grynne, and the paths of movement left behind in the snow afterwards. We draw on Manning's work in order to trace the major and minor gestures running through grynne, as an analytic starting point for educators considering the role early years pedagogy might play in planetary sustainability. Thinking beyond the notion of humans as masterfully in control of environment, Ingold's notion of correspondence offers a counter, advocating for a 'lifetime of intimate gestural and sensory engagement' as a way of learning to attune more deeply to place and take seriously the way in which place and humans mutually shape each other. In a place where seasonal temporality matters, in extreme ways that change how children's bodies can move, we consider what children's entanglement with snow can teach us, educators as well as researchers, about education for sustainability.

Light and its spectrum are central concepts in many introductory physics, astronomy, geology, and conceptual physics courses. The Sun and its spectrum are usually primary examples, likely due to the Sun's everyday familiarity and the full spectrum it generates when dispersed. To enhance such discussions with a hands-on student activity, we've often looked to "sun photometry."

From my home on the west bank of the Columbia River in Richland, Washington (46.3°N latitude), I have an unobstructed view of the sunrise along the east bank during an entire year. As a retirement project after a career of teaching and research in physics, I decided to take photographs of the sunrise for a year and, and at the same time, carry out calculations to determine 1) the hours of daylight on a given day and 2) the elevation angle of the Sun at noon. My goal is to use geometrical diagrams along with a simplified model so that results are very easy to understand. In this model, the spherical Earth revolves around the Sun in a circular orbit, and the parallel sunbeam striking Earth is directed along a line connecting their centers. However, Earth's axis of rotation maintains the same direction throughout its motion around the Sun, which causes the seasons and the variations that we observe. My article entitled "95 Sunrises along the Columbia Riverbank" has recently been published on "Sky and Telescope's" website Stargazers Corner, where collages of the sunrise photos show the path of the sunrise along the east bank. The distance of a sunrise on a given date from that on December 21 shows a sine wave behavior that is expected for such a periodic occurrence. My calculations have been completed using the simplified model. While the direction of the Sun's rays on Earth does change gradually by 0.986° (360°/365 d) during 24 h, the model further assumes that the direction of the Sun's rays on Earth remains constant during a single day, but changes by 0.986° each day. This paper will show how information from two geometrical diagrams can be used to determine the number of daylight hours (defined as the time between sunrise and sunset) and the elevation angle of the Sun at noon. These calculations show a small difference of about 0.2% to 2%, when compared with precisely calculated values available on the internet that include many small corrections to the basic theory. Trigonometry is the highest mathematical level in this paper. A literature search was carried out to find related articles and texts. Many websites on the internet provide a great deal of information about the times of sunrise and sunset for a given location and about the solar elevation angle at noon at any time and location. The algorithms used to determine these values are explained by Meeus. Refs. 2-4 also describe algorithms for very precise calculations should the reader wish a comparison.

In this paper, an experimental setup composed of a color-mixing device, power supply, and spectrometer is developed. This setup is available for students to do hands-on color mixing with red, green, and blue light in undergraduate labs. LED volt-ampere and spectrum characteristics are investigated. The apparatus was used to perform additive color mixing, and visual colorimetric parameters such as color coordinates, dominant wavelength, and color purity were obtained. This will help students understand the physics of LEDs and chromaticity. In addition, this experiment is useful in introducing topics such as the CIE chromaticity diagram and human perception of colors.

In many introductory physics classes, diffraction of light is introduced first, then more advanced diffraction topics such as x-ray diffraction, Bragg's law, and crystallography are covered. Since using x-rays raises safety concerns and atomic spacing in a crystal is not easy to change, microwaves with macroscopic crystals have been used to study Bragg's law in the undergraduate laboratory. A number of scientific supply companies, including PASCO and 3B Scientific, sell 10-GHz microwave optics systems. However, using these systems within the parameters of the manufacturer's procedure for a Bragg diffraction lab poses some challenges. First, the receiver and transmitter must be manually positioned, making the data collection process slow. Second, the microwaves should be plane waves and the receiver should be located beyond the far-field limit. These 10-GHz microwave optics systems are low power, making them safe for lab use, but this limits the crystal size and working distance between the transmitter and receiver to under 1000 mm. The experimental setup suggested by the manufacturer separates the transmitter and receiver by about 10 wavelengths from the center of rotation. While the bells on the transmitter and receiver help with producing plane waves, it is expected that ideal conditions for Bragg's law are not completely fulfilled. Indeed, the experiment guide warns of errors up to 15% and unexplained peaks in the data.

Until recently, built environments have been designed exclusively to meet the needs of neurotypical populations; however, there is increasing recognition of the need to make built environments more accommodating for neurodiverse populations, including autistic individuals. This scoping review aims to comprehensively explore and synthesise this literature on the internal built environment for autistic individuals providing recommendations for designers, policymakers and clinicians. Five electronic databases were searched, resulting in a total of 28 studies being reviewed. Recommendations are provided for design and construction, lighting, sound, aesthetics, temperature and air quality. While in its early stages, evidence demonstrating the impact that particular qualities of light, colour, sound and spatial planning have on the human sensorium is emerging. In turn, this new knowledge is informing design decisions that are progressing interior environments towards inclusivity. Understanding the positive and negative impacts of decisions made in the design of the built environment has the potential to facilitate the participation and inclusion of autistic individuals.

The reflection and refraction of light are more familiar to students than the reflection and refraction of sound. Reflection and refraction that occur during the transmission of sound waves are common phenomena in everyday life but are often difficult to understand during actual learning. In this study, we developed a sound reflection and refraction test apparatus that can measure sound's reflection and refraction angles by injecting sound using a super directional speaker with excellent straightness. Consequently, moving the sound sensor made it possible to find a point with high sound pressure and measure the sound's reflection and refraction angles. Since this device is similar to the experimental device that measures the angle of reflection and refraction of light, it is expected to be able to phenomenologically compare and confirm the reflection and refraction paths of light and sound.

Despite recommendations from science educational standards which claim that science teaching should engage students in scientific investigations the same way scientists practice their profession to discover the unknown, thereby allowing students to actively construct their own knowledge, a growing body of empirical evidence suggests that this may not be the most effective approach. The present research tests the separate effects of two instructional elements that often co-occur when characterizing scientific investigations in science activities: the role of interacting with investigation materials and the role of telling in teacher guidance. Kindergarten and first-grade students participated in one of four versions of a lesson on light in their classrooms: (1) students were either asked to physically interact with scientific investigations themselves or to watch the instructor perform them; and (2) students were either directly told the concepts the investigations were designed to teach or they only heard neutral guidance. Learning was assessed through change in scores from the pretest to posttest. Results show that answers in teacher guidance resulted in more learning than neutral guidance. There was no effect from manipulating materials. Implications of these results for future research and real-world classroom practice are discussed.

There are several 'cool' mechanisms that result in materials luminescing or emitting light. Artificial luminescence has often been created by mimicking nature and there are many examples of applications in society. It is very likely that most of your students will have observed luminescence in one form or another, such as glow sticks, high-visibility jackets, sea creatures that glow in the darkness of the deep sea, fireflies and highlighter pens. This article explores the nature of luminescence and introduces some interesting natural and synthetic examples. It also reports on some innovative applications of luminescence in food science and medicine, and introduces a range of activities to engage and challenge your students. Luminescence, a term first used by Eilhardt Wiedemann in 1888, is a phenomenon that can be integrated into chemistry, physics and biology studies, and it offers a wow factor for students.

We demonstrated that an optimally designed pinhole camera can be used as an astronomical tool to observe the libration and apparent diameter change of the Moon at night. The libration and apparent diameter change of the Moon were observed using a handmade pinhole camera with a diameter of 0.65 mm and a focal length of 400 mm. It was found that the lunar mare with its characteristic pattern can be observed using this pinhole camera with a resolution of 2.5 arcmin. It was also found that the apparent diameter change of the Moon of about 10% can be observed with this pinhole camera. The pinhole camera used in this experiment is very useful as a handmade scientific educational material for learning the principles of optics and the movement of the Moon.

Refraction is a foundational concept within introductory physics. Physics students need a deep understanding of refraction, including Snell's Law, in order to progress towards more complex optics topics such as lenses and images. Unfortunately, many physics students obtain only a superficial understanding of refraction. Although many students can use Snell's Law to perform basic calculations, the mathematical relationship is often divorced from students' conceptual knowledge, which often harbours misconceptions. In this article, we describe a sequence of instructional activities that we have used in an introductory optics course that aims to address common issues of students' learning of optics. Instead of leading with Snell's Law and emphasising calculations, the instructional sequence places conceptual understanding in the foreground. Mathematical representations are introduced only after students have developed a conceptual foundation; in this way, mathematics becomes integrated with students' conceptual understanding rather than existing apart from it. After describing the instructional sequence, we present the impacts of instruction on student thinking and also suggest potential applications of the instructional principles that guided our decision-making.

Teaching the noncommutativity of the product of matrices to high school or college level students is a difficult task when approached from a purely formal perspective. The aim of this paper is to present a simple experimental activity for teaching the noncommutativity of the matrix product, based on the Jones calculus, a mathematical formalism for describing polarised light by means of matrices and vectors. This activity can also be useful to introduce students to the use of matrices in physics, and to illustrate how abstract mathematics can become a powerful tool to help us explain and describe the real world.

In this paper, a simple method is described for visually demonstrating that the wavelength of light reduces when entering a medium of higher refractive index. When a violet laser (405 nm) is reflected off the surface of a Blu-ray disc (track spacing 320 nm) diffraction cannot occur since the wavelength is greater than the track spacing. However, in water (refractive index 1.33) the wavelength of violet light reduces to 304.5 nm and therefore first-order diffraction can occur when a violet laser is reflected off a Blu-ray disc submerged in water. A violet laser was reflected off a DVD in air, and one diffraction order was seen, but two orders were observed when the disc was immersed in water. Red, green, and violet lasers were reflected off CD, DVD and Blu-ray discs and the number of observed diffraction orders compared with theory. When a violet laser was reflected off a CD in air, three diffraction orders were seen, however five orders were observed in water. The use of tonic water in the experiments enabled the diffraction orders to be seen more easily because violet light causes the quinine in tonic water to fluoresce.

Ever since Newton's groundbreaking work on the composed nature of light, additive colour mixing (and its laws) are subject to the interest of physicists as well as other sciences. In this paper, we present a setup for simple lab or home experiments on additive colour mixing and the laws of colour mixing. Students use the screen of a laptop or handheld device as (coloured) light source for respective experiments and can directly inspect the results of a superposition of different colours. With basic skills in designing presentation slides students can autonomously implement mixing experiments and explore the secrets which inspired GraBmann, Maxwell, and others.

The refractive index of a liquid is known to depend strongly on the temperature gradient of liquids. When a laser beam passes through a transparent material going through thermal diffusion, the light projected onto a screen will be displaced in relation to the thermal diffusivity. A simple apparatus is used to measure the time evolution t of the laser beam displacement h and/vs. the position of the laser beam on the liquid container y whose liquid medium is going through thermal diffusion. Thermal diffusion dynamics can then be revealed. The thermal diffusivity of glycerol, ethanol, DI water, and NaCl aqueous solution has been measured. This simple procedure can demonstrate refractive index and thermal diffusivity in advanced high school physics courses.

Diffraction refers to a kind of optical phenomena which occurs when light approaches an element (object or aperture) whose features are in the range of the illuminating wavelength (small apertures, sharp edges). It can be explained by means of the undulatory nature of light or also geometrically by using simple ray optics. Diffraction phenomena are impressive and not intuitive, so it makes them very interesting to bring examples to the classroom. The most popular diffraction experiments show effects in Fraunhofer regime, that is to be said, far from the diffractive object. Common examples are the single or double slit experiments. In this manuscript, we propose and show a less common diffractive effect that occurs in the Fresnel regime, near to the diffractive object. It is the Talbot effect or self-imaging phenomenon, which appears by illuminating a diffraction grating with a collimated monochromatic beam. It consists of the apparition of replicas (self-images) of the grating intensity pattern at periodic distances, multiples of the so-called Talbot distance. We show how this effect may be shown into the classroom with cheap and easy to find elements. In addition, we take advantage of its dependence on the coherence degree of the source to introduce the concept of optical coherence and show its effect on the contrast of the Talbot self-images. These experiments could be appropriate for undergraduate students or introductory physics courses.

Data from the Kepler satellite were analysed using the Mikulski Archive for Space Telescopes database. With the participation of 53 students, we determined the parameters of the HAT-P-7b (Kepler-2) exoplanet system (transit duration, planet-to-star radius ratio, orbital period, semi-major axis and star mass). We used approaches that are easy to understand and apply to secondary school students as well. In this way, they were able to gain an insight into the essential process of light curve analysis.

Pulse oximetry has become the standard of care in operating rooms, intensive care units, and hospitals worldwide. A pulse oximeter continuously and noninvasively monitors the functional oxygen saturation of hemoglobin in arterial blood (Sa[subscript O2]). Sa[subscript O2] is so important in medical care that it is often regarded as a fifth vital sign. Before pulse oximetry, arterial puncture for blood gas analysis was the only method available to determine Sa[subscript O2] and to identify the presence of hypoxemia. Pulse oximetry is based on the principle that oxygenated hemoglobin (O2Hb) absorbs more near-infrared light than deoxyhemoglobin (HHb) and HHb absorbs more red light than O[subscript 2]Hb. It is important to understand the principles of pulse oximetry, how the equipment works, and its limitations to interpret the information it provides. Accordingly, we used colored balloons to introduce the physics of how a pulse oximeter detects and measures oxyhemoglobin and deoxyhemoglobin in pulsatile (arterial) and nonpulsatile (venous and capillary) blood. The foundations of oximetry started in the 1700s with Johann Lambert (1728-1777). We approached this complex physics in a straightforward way while still providing an understanding of the fundamental concepts developed by Johann Lambert in 1760.

Performance-based architectural design pursues building performance objectives like energy efficiency to guide design decisions. Nevertheless, these informed decisions are usually made according to performance simulation software results, which are quite effort-consuming and tedious. Meanwhile, this low feedback efficiency blocks architects' mind flows from creating new design alternatives. Therefore, the current authors develop a digital platform by coupling Internet of Things (IoT) and Mixed Reality (MR). It streams and visualizes real-time sensory data of indoor illuminance into an MR glass HoloLens. It enables students to intuitively observe spatio-temporal illuminance fluctuation when manually modifying the physical shading device model. Therefore, they can quickly learn how design decisions influence indoor illuminances. At last, in the validation experiment with first and second year students in an architecture school, we compare this platform with two other teaching methods and platforms. Experimental results identify that the IoT-MR platform can effectively attract students and increase their learning effects.

It is often necessary to enrich the teaching environment in order for students to learn optics in depth and to interpret the real optical situations with the information they have learned. In this study, a virtual teaching environment was developed using by Algodoo, a 2D simulation software. An eye model was created in order to explain the formation of the image in the eye in the teaching environment. Also, a cactus type light source model has also been developed to demonstrate that the image can be created in optics by using rays other than special rays. In order to show the success of the virtual teaching environment in modelling, previously known situations that the students had difficulty in understanding were simulated. Finally, some suggestions were made about the use of the virtual teaching environment.

The Arduino board and its communication with several sensors are becoming more and more popular in the physical science community. They offer inspiring possibilities for learning different physical concepts. In this article, we focused on creating a very practical educational system for experimenting with diffraction of laser light and graphically visualizing the distribution of light intensity in space, which is impossible to perform it with the devices available in the educational laboratories of physics. The main elements of this configuration are the Arduino UNO microcontroller board, the BH1750 sensor and the NEMA17 motor and its A4990 driver. The results' graph is displayed in real time on the computer using the Data Streamer add-in. We see that the abbreviated curve corresponds well to the theory. In addition, feedback from the participants in the test activity of the device showed that they were satisfied with its operation and its contribution to the understanding of diffraction. Therefore, we believe that the device presented can play a very important role in the diffraction phenomenon learning because of its high precision and reliability in the measurements.

In this paper, we propose a simple yet generic and versatile method to measure the position of a moving body as a function of time. Apart from very basic equipment such as carts and wheels, only a laser pointer or a similar device and a smartphone are necessary. By attaching a source of light to a cart and video filming its movement on a horizontal plane under the gravitational force, the position of the cart as a function of time can be recorded without any calibration and using one of the many free apps. The obtained results for the cart acceleration under a constant force were in very good agreement with Newton's second law. The inexpensive equipment and the possibility of taking data at very short intervals allow different experiments in mechanics to be performed, for example to demonstrate the conservation of energy and momentum in mechanics or to investigate complex movements.

In this article, the author presents a Desmos activity where students adjust the measures of angles in radians to reposition a laser and a mirror so the beam passes through three stationary targets. This Radian Lasers activity can be extended to simulate project-based learning (PBL), a pedagogical approach for applying concepts and skills from various disciplines to a specified project. Students apply what they learn about angle measure and light reflection by designing a periscope.

Students are introduced to the term wavelength in optics at school level. In this paper, we present an inexpensive and simple method to measure the wavelength of the light of a light emitting diode using a light depending resistor. This experimental set-up is developed at Science Laboratory, Nehru Planetarium (Mumbai), India. It is useful as an experimental tool to teach the concepts of light in a simpler way.

This study aimed to investigate how inquiry-based experiment-integrated science games affect the achievement and scientific process skills of 5th grade students. The topics of "Light and Sound" and "Electricity in Our Lives" were selected for the experiment. Two groups totaling 41 students participated. The research method consisted of a quasi-experimental design utilizing an experimental and control group. While 21 students in the experimental group played inquiry-based experiment-integrated science games developed by the researchers, no educational game was included in the lessons of the control group of 20 students. "Light and Sound Achievement Test", "Electricity Achievement Test" and "Science Process Assessment" were applied to both groups in the form of a pre- and post-test. To analyze the data, independent t-test was used. Students in the experimental group were more successful than the control group in their scores for both achievement and scientific process skills. It can be inferred from the results that students develop better achievement and scientific process skills by playing science games. It is recommended that such games should be integrated into the science classroom.

The objective of the present study is to determine the effect of the process of designing a slowmation (SMA) on the development of 21st century skills of "learning and innovation" in 4th grade science class "Light and Sound" and "Planet Earth" units. Study group included 44 students attending 4th grade in two private schools in Southeastern Anatolia region. Four female and five male, a total of nine focus students were determined in the study group where the application was implemented. The study was conducted in 17 weeks (51 periods), out of which six weeks spanned the pre-application process and the application lasted for 11 weeks. Different data collection tools such as video records, semi-structured interviews, group audio recordings, 21st century learning and innovation skills scale r and student diaries were used to collect data in the study. Quantitative data were analyzed and interpreted using SPSS software. Qualitative data were analyzed with descriptive analysis. Overall results of the study demonstrated that slowmation application resulted in the development of 21st century learning and innovation skills, namely creativity and innovation, critical thinking and problem solving, collaboration and communication skills.

A new version of SALS (Submersible Audible Light Sensor) consists of a wireless light-detecting probe Bluetooth® connected to the iOS SALS App. As in previous versions of SALS, changes in detected light are converted to changes in sound, the latter now rendered with iPhone or iPad audio. The SALS probe assists the student with visual impairment in a variety of science activities, including those involving liquids. For example, when the SALS probe is placed in a reaction vessel, changes in light intensity caused by a chemical reaction or color indicator change are converted to changes in tone in real time. The SALS app also provides options to store tones from experiments and to convert tones to Hertz for quantitative expression of data.

Consumer electronics are creating huge job markets for graduates with the programming back-ground, and more and more computer science departments are launching embedded software subjects to meet this demand. However, most students majoring computer science do not have the background in electronics, or even circuits. Due to this reason, how to convey the abstract knowledge on embedded software tangibly to students in computer science is a significant challenge in teaching to bridge the gap between the limited background and curriculum requirements. This paper addresses this challenge by proposing a student project to develop and pilot test a mobile robot platform, and a peer competition with the robots developed by other students. The project requires students to develop a mobile robot using commercial sensors and actuators for simultaneous light source seeking and obstacle avoidance. The development and assembly of such a system stimulate students' interest in this subject and provide them with a concrete understanding of embedded systems. The algorithm design and implementation enhance their theoretical knowledge gained from lectures. To facilitate the development, this project is partitioned into multiple parts and we provided a one-hour tutorial every week for all parts. The components include basic simple concepts such as input/output programming, intermediate tasks such as reading sensor data and controlling motors, and advanced topics such as multi-threading to simultaneously control multiple software methods. The final competition motivates students to develop robust and optimal programs. It helps them accumulate practical knowledge about performance limits of some electronic devices and calibration techniques to improve the performance. The pilot testing of this course has been conducted for two semesters and all major issues have been addressed. A comprehensive survey was conducted at the end of the course to get student feedback on different pedagogical aspects of the course. The evaluation results demonstrate the effectiveness of the project in enhancing students' understanding of electronics, knowledge of programming to support embedded systems, and critical thinking.

In some school, teacher-centered is commonly found in the learning process. The learning process itself is still in the form of direct transfer of knowledge from teacher to students. Actually, students will learn better if they are engaged in a meaningful learning activity. STEM project-based learning is one of the alternative teaching strategies that engaged students in meaningful learning. The aim of this study is to investigate the impact of STEM project-based learning on students' creativity in the topics of light and optics. The study used qualitative research with the narrative design. Data collection technique that used is observation. The population is eight grade students in one of Junior Secondary School that is located in Bandung, Indonesia. The sample consists of 25 students that chosen based on purposive sampling technique. The data is obtained through Creativity Product Analysis Matrix (CPAM). There are three creativity dimensions that used in this study which are resolution, elaboration and novelty dimension. Students' creativity is obtained as much 76% which categorized as good. Based on the result, STEM project-based learning give a good impact on students' creativity. STEM project-based learning can be used as alternative teaching strategies in Junior Secondary School.

Objective: This study aims at investigating the relationship between reactive agility and cognitive performance of amateur male football players. Material and Method: Twenty-four male football players from 11 Nisan Sports Club in Sanliurfa struggling in Regional Amateur Football League (BAL) participated in the study voluntarily. The mean age, height and weight of the football players participating in the study were 22.88 [plus or minus] 4.15 year, 176.76 [plus or minus] 5.90 cm and 69.76 [plus or minus] 7.61 kg, respectively. Psycho-Technical Vienna system was used for Participants' Cognitive tests, IQ (SPM), Continuous Attention (SIGNAL, SIGINAL TIME), Visual Memory (TAVTB), Determination Test (DT, DT TIME), Attention and Problem Solving (COG), Line Tracking (LVT), and Speed Distance Estimation (HMT). For the reactive agility test, the Fusion Sport Smart Speed device was used. Correlation statistics were used for the relationships between the variables. SPSS 23.0 package program was used for statistical operations. For the interpretation of statistical analyze, the significance level was accepted as 0.05. Results: There was no significant relationship between IQ (SPM), Continuous Attention (SIGNAL), Visual Memory (TAVTMB), Determination Test (DT), Attention and Problem Solving (COG), Line Tracking (LVT) with reactive agility values of male football players (p > 0.05), a significant relationship was found between Continuous Attention Reaction Time (SIGINAL TIME) the rRaction Time of the Determination test (DT TIME) and Speed Distance Estimation (HMT) (p < 0.05). Conclusion: As the content of the reactive agility test was based only on the speed and reaction speed against light and noise, it was found that the players were only associated with speed distance estimation and response time among the reactive agility performance and the cognitive tests. In order to determine the relationship between reactive agility and cognitive performance, there is a need for new reactive agility tests which are designed according to the branches where there is a distinction between competitor and team player requiring visual memory, attention, reaction, and double action skills.

This study was carried out to determine the effect of guided inquiry teaching method (GITM) on secondary school students' achievement in light and sound waves in Abuja, Nigeria. A sample of 95 students drawn from a population of 1,832 was used for the study. Two research questions were raised and answered in the study using mean and standard deviation while two hypotheses formulated were tested using ANCOVA at 0.05 level of significant. Quasi-experimental research design comprising experimental and control groups was used for the study. The instrument for data gathering was light and sound waves achievement test (LASWAT). A validity index of 0.86 and a reliability index of 0.87 were respectively obtained for LASWAT. Students in both groups were given pre-test before instruction. During the instruction, the same content was presented to the two groups for a period of six weeks and thereafter a post-test was administered. The findings of the study revealed that the experimental group significantly scored higher in post-test than the control group. This is evidenced in H01, F(1, 93) = 85.476 and P = 0.000 < x = 0.05. The results also showed that gender has no significant influence on mean achievement scores of students taught light and sound waves using GITM as revealed in H02, F(1,48) = 0.656 and P = 0.413 > x = 0.05. The findings simply imply that GITM is superior to the conventional method in enhancing students' achievement in light and sound waves irrespective of gender in Abuja. Nigeria.

Student's mental representations of physical concepts are often different from those of scientists. The research aimed to identify and compare mental representations of light propagation time by school children aged 10 (132 subjects), and 14 (109 subjects) years old. This research was conducted through individual interviews in which the students were asked to locate light propagation time in various tasks-experimental situations. The results of this research show that even though the students of two groups face difficulties in understanding light propagation time, as they grow older, they make statistically significant progress in constructing the conception of light propagation time. These findings allow to seek out educational perspectives on the understanding of the conception of light propagation time in organised scholastic environments.

Light pollution is nowadays well known all over the world and may negatively cause disturbance to human and have diverse effects. This study aims to identify the views and opinions of the Islamic University of Gaza students on light pollution and then to create awareness among them about the risky problem facing rapidly our society. The study is based on the survey questions and semi-structured interviews and then the data is collected from the survey questions and semi-structured interviews were qualitatively analyzed and quotes from the students' statements were included. Most of the students recognized that excessive lighting can adversely affect a person's health. The results also show that 40.0% of the students feel that the area outside of their residence is at night is "Fair Brightness", 29.2% "Bright as day", 13.8% "Pitch Black", and 16.9% "A Little Black". 90.8% of the sample are familiar with light pollution, but 9.2% is not. Some suggestions and recommendations will be made for controlling and reducing light pollution to have a healthy society. [Note: The volume number (11) shown on the PDF is incorrect. The correct volume number for this article is 10.]

Trillion Theory (TT), a new theory, estimates the cosmic origin at one trillion years. This calculation of thousands of eons is based upon a growth factor where solar systems age-out at a max of 15 billion years, only to recycle into even larger solar systems, inside of ancient galaxies that are as old as 200 billion to 900 billion years. TT is a new brash cosmology theory proposing many new radical ideas. These proposed ideas should be given credence, as such small changes can give rise to large consequences in speeding the present cosmic revolution. All astronomers must undertake greater introspection by performing forensics on black holes throughout cosmos. This article discusses the following topic areas: TT's background, big questions TT answers, the basics of TT, how Earth formed into a sphere, how the sun formed, law of all spheres by T Theory, how the solar system formed, how galaxies became cosmic hotels, materials used to build cosmos, how cosmos grew ever-larger, cosmic design in Trillion Theory, the goals of TT, and proofs of TT. [Note: The volume number (11) shown on the PDF is incorrect. The correct volume for this article is 10.]

We calculate the frequency of matter-wave of electrons orbiting the hydrogen nucleus at the ground state. It is the same as the value of light frequency corresponding to the ground state from the Rydberg's formula. The result will stimulate students' interest to further understand the mechanisms of quantum theory.

Web-based applications in education seem to be increasing day by day. As in all fields of education, web-based teaching practices are being developed to make the subjects learn better in science. The web-based instruction on science education for 6th-grade students, light and sound unit, a reflection of light was designed according to Dick and Carey instructional design model. From the experimental design, a single group pre-test-post-test quasi-experimental research model is used. The study group consists of 20 students in the 6th grade of a middle school in a 2015-2016 academic year. Data obtained within the scope of the research were analysed by descriptive (frequency, percentage) and predictive (t-test of dependent samples) data analysis methods from quantitative data analysis methods. The results of the research show that the motivation levels of the students are related to the attitude and academic achievement of the students after science course. However, it is observed that the implementation is a meaningful effect on students' academic achievement on the reflection of the light, but does not make a significant difference in their attitudes and motivations. It is thought that the results of the research will contribute to the instructional design studies to be done in science education.

The interference pattern between two harmonic oscillations with slightly different frequencies are called beats. The beats, as a combined motion, have two different periods, one approximately equal to the period of the original oscillations, and another that is significantly longer and is related to the variable amplitude of the motion. The main objective of this presented work is to engage students' attention and demonstrate in a simple way the concept of mechanical beats as a resultant motion of combined oscillations, but also to experience it through a visual projection. The proposed experimental setup is constructed in a way that satisfies both objectives and it consists of two parts that allow us to demonstrate in real time the combination of two harmonic motions. In the first part, the resultant motion is generated by the oscillations of two parallel rulers equipped with mirrors, and in the second part the visual demonstration of the beat occurs on a phosphorescent rotating foil by using a blue violet laser beam.

This work describes the design and testing of a low-cost light-emitting diode (LED)-based nephelometer for turbidity analysis. It also describes the use of this nephelometer for context-based learning (CBL) experiments designed for teaching laboratories. The LED nephelometer is simple, low-cost, and robust, providing similar results as a commercial device. Data collection and analysis is quick and intuitive, allowing time and opportunity for discussion about the analytical process and the chemistry involved. The experiments described here are based on real-world applications to emphasize the usefulness of chemical analysis and quantification of turbidity in everyday life.

Here, we present a 3D printed experimental apparatus that students can use to acquire interference and diffraction quantitative data from light passing through a single or double-slit experiment. We built a linear screw stage with a multiturn potentiometer connected to its leadscrew as a position sensor. Using an Arduino, we collected light intensity data (from a photodiode mounted in the linear stage) as a function of position. The apparatus is a low-cost and compact alternative with data acquisition to optics physics laboratories.

In this work, we report the development of a low-cost Arduino-controlled device for didactic activities in light polarization. The main body of the prototype was designed and produced using laser-cut medium density fibreboard parts, including gears and pulleys. As a light source and detector, a 532 nm laser pointer and a light dependent resistor were used, respectively. The moving parts (light source and detector) are controlled using a stepper motor (28BYJ-48) with the ULN2003 driver. The apparatus was tested with glass and plastic (polystyrene) slides. The results show that the prototype can distinguish between parallel and perpendicular polarization (to the plane of incidence). In addition, it is demonstrated that the prototype can be satisfactorily applied to determine the Brewster's angle, even for solids with close refractive indexes.

The Crookes radiometer (also known as a light mill) is a fascinating sunlight-powered device, in which a set of vanes is placed inside a glass bulb within which a partial vacuum has been pulled. The vanes then rotate when sunlight shines on the bulb. The reason for the turning of the vanes was subject to intense debate and many students still have an incorrect understanding of the device. We analyse the forces involved in a much less well-known radiometer (called the Hettner radiometer) and show that this can help us to understand the forces involved in the Crookes radiometer in a more unified way.

Light spectrum dispersion is an exciting subject in science because of its beautiful atmospheric colour phenomenon which attracts students. However, to see the phenomenon is not easy since it needs a spectrometer, which is commonly expensive. Therefore, the present study aims to describe a low-cost spectrometer for investigating lighting spectrum and analysing the purity of honey as a pedagogical students' project. The spectrometer was constructed from a webcam connected to a laptop, a free spectrometer software, DVD disk, and black cardboard. The calibration of the developed spectrometer used an Argon (Ar) lamp. Afterwards, measurement tests were carried out by using Neon (Ne) and Xenon (Xe) lamps. A white light-emitting diode was used as a light source to measure several types of honey wavelengths. The results from the experiment show that the wavelength of Ar, Ne, and Xe are (503 ± 4) nm, (463 ± 3) nm, and (451 ± 3) nm respectively. The measurement accuracy of the spectrometer is 99.5%. In addition, the commercial honey characterisations show that pure honey tends to have an excellent and smooth spectrum with one peak. On the contrary, the adulteries honeys show a rough wave with many peaks representing the inhomogeneous ingredients. It is found that the average accuracy for honey spectrum is 99.8%. Moreover, the low-cost spectrometer can be built and used easily by students for educational purposes.

The refractive index (RI) is probably the single most important parameter in optical systems. Chromatic dispersion, on the other hand, indicates how the RI depends on the wavelength and is central in, e.g., optical communication systems. Chromatic dispersion also plays an important role when teaching optics due to the captivating natural phenomenon of the rainbow and the white light decomposition with a prism. In this work, we propose and explore a method to characterize the refractive index of transparent liquids in the visible range without any dedicated equipment or device (such as prisms, goniometer, laser, detector, etc.).

Two misconceptions about the mechanism of image formation in the human eye are common among students and even in textbooks and other teaching materials. The first attributes all refraction to the eye lens; the second treats the eye as a pinhole camera. To reduce these persistent conceptions of students, a series of simple experiments is presented using a water-filled fishbowl as a model of the eye. The model is used to demonstrate the propagation of light through the eye and the image formation on the retina in normal vision, nearsightedness, and farsightedness. The model also allows visualization of the corrections of malfunctions of the eye.