The point particle is an idealized object where rotational and vibrational motion is ignored. Nevertheless, in many cases such degrees of freedom play a significant role. For example, the rotation and vibration of a molecule is an important "reservoir" of its internal energy. The excitation of these types of motion can occur during the…

The question from the title is raised because in almost all introductory physics courses/textbooks the atmospheric pressure has been attributed to the weight of the column of air from a given level in the atmosphere up to its top. "Air is pressing on air." However the same textbooks, in the chapter on the kinetic theory of gases, tell…

This article describes a simple way to introduce nanomaterials using the presence of carbon nanodots (CNDs) in widely available food. Budweiser® beer and Coca-Cola®, commercial foods that are commonly accessible, were utilized to demonstrate the optical property of nanoparticles. Specifically, green and violet laser pointers were employed for the…

The saga of the search for the ultimate constituents of matter has long been one of finding a seemingly fundamental structure that, in turn, was found to be made of even smaller building blocks. Matter is made of molecules. Molecules are in turn made of atoms, which are themselves made of electrons and atomic nuclei. The nucleus consists of…

Friction is one of the common forces that affect our everyday life and one of the oldest problems studied in physics. An interpretation of its nature is included in all general physics courses, in both high school and college. The desire and need to better understand it guided a long list of scientists who devoted themselves to the study of…

Climate is a topic of great concern to students, but it remains difficult to discuss scientifically. We are bombarded daily by emotional messaging for and against the proposition that human activities are altering the climate in ways that may have catastrophic effects. But it often seems that those predictions rest entirely on massive computer…

Many introductory and nanotechnology textbooks discuss the operation of various microscopes including atomic force (AFM), scanning tunneling (STM), and scanning electron microscopes (SEM). In a nanotechnology laboratory class, students frequently utilize microscopes to obtain data without a thought about the detailed operation of the tool itself.…

The concept of "seeing by feeling" as a way to circumvent limitations on sight is universal on the macroscopic scale--reading Braille, feeling one's way around a dark room, etc. The development of the atomic force microscope (AFM) in 1986 extended this concept to imaging in the nanoscale. While there are classroom demonstrations that use…

In a recent issue of "TPT," Gordon Gore made interesting observations about the red or yellow fluorescence when laser beams are passed through olive oil. With the excellent visuals contained in that article, we present a pictorial explanation of the questions that were raised in Ref 1 ("Fun with Fluorescence in Olive Oil,"…

Diffraction and interference are phenomena that demonstrate the wave nature of light and of particles. Experiments relating to the diffraction/interference of light can easily be carried out in an educational lab, but it may be impossible to perform experiments involving electrons because of the lack of specialized equipment needed for such…

Feynman diagrams are introduced in many physics textbooks, such as those by Alonso and Finn and Serway, and their use in physics education has been discussed by various authors. They have an appealing simplicity and can give insight into events in the microworld. Yet students often do not understand their significance and often cannot combine the…

What do basketball teams have in common with radioactive nuclei? It turns out, there is more here than first meets the eye. The National Collegiate Athletic Association (NCAA) basketball tournaments feeds fans' craving when NBA competitions are not in swing, and the college tournament time has been referred to as "March Madness" or…

The experiment proposed here illustrates some concepts of tomography via a qualitative determination of the relative concentration of various dilutions of food dye without "a priori" knowledge of the concentration of each dye mixture. This is performed in a manner analogous to computed tomography (CT) scans. In order to determine the…

The motion of charges around a centrally charged object is often compared to gravitational orbits (such as satellites around planets). Recently, a video taken by astronaut Don Pettit onboard the International Space Station shows water droplets orbiting a charged knitting needle. Here we attempt to model this motion and estimate the charges on the…

We describe the principles of macroscopic charged particle detection in the laboratory and their connections to concepts taught in the physics classroom. Electrostatic dust accelerator systems, capable of launching charged dust grains at hypervelocities (1-100 km/s), are a critical tool for space exploration. Dust grains in space typically have…