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Tangential and Normal Acceleration Components in Projectile Motion
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| Pengarang | : | Felipe Melo Santos; José G. S. Duque; Wagner Ferreira Santos |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 758-762 |
| Abstrak | : | In this work, we analyze projectile motion in terms of its normal and tangential acceleration components. It is well established in most high school and university physics textbooks that projectile motion can be studied in the Cartesian plane as a composition of two independent motions: one in the x-axis orientation (uniform rectilinear motion) and the other in the y-axis orientation (uniformly varied rectilinear motion). It is important to additionally consider that this motion is subject to Earth’s gravitational field, which acts perpendicular to its surface in the downward direction. However, since the velocity vector varies in both magnitude and direction throughout the projectile motion, it is possible to view it from a different perspective. In this viewpoint, the acceleration can be decomposed into two components: a tangential component, caused by changes in the magnitude of the velocity vector, and a normal component, caused by changes in the direction.. |
Energy Flows at Earths Surface
| Pengarang | : | Michele Dragoni |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 754-757 |
| Abstrak | : | Two energy flows converge at Earth’s surface: one coming from the Sun and the other from Earth’s interior. Their intensities are very different, the first one being overwhelming. Solar heat is responsible for all processes involving the outer fluid layers of Earth (atmosphere and oceans). In contrast, processes occurring in Earth’s interior, including convection in the core and in the mantle as well as surface manifestations such as seismic and volcanic activity, are unaffected by solar energy, being due only to internal heat. Solar energy only controls the surface temperature of Earth, which is a boundary condition for internal processes. The argument requires use of basic concepts in thermodynamics, such as the radiance and the spectral radiance of a blackbody. The equation of heat conduction in spherical symmetry is derived and solved for a simple model, yielding an approximate temperature profile within Earth. |
Absence of Hydrostatic Pressure in Free Falling Mercury
| Pengarang | : | Ivana M. Krulj; Josip Slisko |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 750-753 |
| Abstrak | : | We present a new demonstration of the absence of hydrostatic pressure of mercury in free fall. We show that the mercury starts oscillating in a U-tube closed at one end when the system is in weightlessness, as well as how the described experiment can be implemented in physics teaching. It is understood that handling mercury should be avoided for safety and health protection. The presented experiment can be used through video frames or the video itself, which we are ready to provide to interested teachers, should they recognize the potential of our manuscript for application in their practice. |
Diffusion, Electrophoresis, and Electric Field Visualization
| Pengarang | : | Mickey Kutzner; Chloe Gaban; Sable Canales |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 745-749 |
| Abstrak | : | We describe three fun and relatively inexpensive lab activities that follow the movement of food coloring dye through agar–agar gel. The labs include i) diffusion, ii) electrophoresis, and iii) electric field visualization. The experiments bridge the disciplines of physics, biochemistry, biology, and forensic science. |
Measuring the Magnetic Field of a Solenoid Using a Reed Relay
| Pengarang | : | Mária Kladivová; Peter Duranka |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 742-744 |
| Abstrak | : | The magnetic field along a solenoid axis is mapped using a magnetic reed relay1 as the magnetic field sensor. The presented experimental setup can be included in laboratory practicals or used as a demonstration experiment for high school as well as undergraduate students. |
Electric Field Activity for Continuous Charge Distributions
| Pengarang | : | Andrew Ferstl |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 740-741 |
| Abstrak | : | These problems can be challenging for students, and education research has examined the difficulties they have.1–6 The purpose of this article is to present an activity that uses a simulation to replace an otherwise difficult experiment that would measure the electric field of these types of continuous charge distributions. A module on learning the electric field could incorporate this activity, which uses a PhET simulation7 to compare predictions to simulated results. |
Exponential Decay Experiments
| Pengarang | : | Thomas B. Greenslade, Jr. |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 738-739 |
| Abstrak | : | When I came to Kenyon College in 1964, I found that my new colleague, Franklin Miller Jr., had recently written a successful proposal for a 5-Ci plutonium-beryllium neutron source. In the last experiment of the year for the premeds that I was teaching that year, we irradiated U.S. silver half dollars with neutrons and followed the exponential decay of the longer lived of the two silver isotopes that were produced. Eventually, all students taking physics at Kenyon did this experiment, although more advanced students studied the system in more detail. |
Radioactive Decay Chain Board Game
| Pengarang | : | Welica P. S. Freitas; Lisiane B. Calheiro; Alem-Mar B. Goncalves |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 736-737 |
| Abstrak | : | We present here a board game that introduces the concept of a radioactive decay chain. The game explores the four natural decay series, permitting students to identify alpha and beta decays. All the parts can be made with wood/plastic panels using a laser cut/engraver machine or be printed on paper sheets using a conventional printer. |
Nuclear Physics with MightyOhm: Evidence of Radiation Scattering
| Pengarang | : | Calin Galeriu; Geoffrey Esper; Cristina Miron |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 731-735 |
| Abstrak | : | Great physicists like Arthur Compton1 were able to design and build new scientific instruments. Many times, this has opened the door to new physics discoveries. Our students, as well, should get more involved with this creative method of doing science. One way of promoting this type of experimental research skill is to teach them how to make measurements using the very popular and affordable Arduino Uno microcontroller board and its compatible sensors. |
Three Methods to Estimate the Refractive Index of a CD-ROM with a Smartphone
| Pengarang | : | Wei Zhuang; Leyao Jiang; Jiasheng Wu; Caojin Yuan; Jiaxuan Wang; Jiawei Song |
| Nama Majalah/Jurnal | : | The Physics Teacher |
| Volume / Edisi | : | 62 (No. 9) |
| Halaman | : | 728-730 |
| Abstrak | : | The refractive index (RI) is considered one of the most fundamental optical features of a sample, and estimating the RI, especially of a liquid, has become a popular topic in various STEM classes and events since it can help students to understand refraction conceptually.1–5 However, the RI can be estimated not only by Snell’s law, but also by the critical angle of total reflection as well as Brewster’s angle, where the latter two cases can be viewed as special cases of the refraction with no refracted ray and no reflected ray, respectively. Therefore, this paper proposes three different approaches to estimating the refractive index of a sample with simple apparatus, corresponding to the three cases of refraction when light travels through different media, with the aim of helping students establish the connection of different optical phenomena and understand refraction more deeply. |