The flow of air around a baseball and over the seam acts to slow the ball and to deflect it sideways. Turbulent flow can be visualized, and sideways deflection of the ball can be observed clearly if the ball is dropped in a glass fish tank and filmed with a high-speed camera. Results are presented for a baseball and also for a billiard ball with a…

The nature and cause of the phases of the moon are widely misunderstood. Perhaps the problem is a general decline in scientific literacy, or maybe it is the loss of direct and regular observation of the moon in society generally. Many people do not see the moon as a half-illuminated sphere. Adults are often surprised to realize that the moon can…

Physlets, educational applets developed at Davidson College, are a widely used teaching resource designed to simulate a variety of physical phenomena. Originally, each Physlet was a Java simulation that was embedded in an HTML page as an applet and then customized using JavaScript to simulate a specific physics concept. The use of Java to simulate…

Physics teachers around the world are trying to create classroom environments that would allow life science students to be more intrinsically motivated in their work. These efforts include, among others, matching classroom activities to students' interests as well as structurally variable activities to match different student abilities. While…

An ice hockey player can strike a puck at speeds up to about 45 m/s (100 mph) using a technique known as the slap shot. There is nothing unusual about the speed, since golf balls, tennis balls, and baseballs can also be projected at that speed or even higher. The unusual part is that the player strikes the ice before striking the puck, causing the…

Dark matter comprises most of the matter in the universe, yet physicists are unsure of its nature. A significant effort is devoted in contemporary research to attempts to understand dark matter, making it a both captivating and relevant area of astrophysics to discuss in a classroom setting. What is more, the physics behind these experiments is…

Equilibrium is an essential concept in undergraduate physics curriculum as it integrates Newton's laws and torque. The importance also comes from its wide applications in mechanics and biomechanics. Simulations of Back and Arms are developed mainly for the undergraduates who major in physical therapy and health sciences. They are implemented as…

The Exploding Carts is a popular introductory physics activity in which a one-dimensional explosion is simulated utilizing two dynamics carts that are pushed apart by a spring-loaded plunger released from one of the carts. Traditional treatments of the Exploding Carts usually involve multiple trials where the mass of one or both of the carts is…

Students are well aware of the effect of the deflection of sports balls when they have been given a spin. A volleyball, tennis, or table tennis ball served with topspin results in an additional downward force that makes the ball difficult to catch and return. In soccer, the effect of sidespin causes the ball to curve unexpectedly sideways,…

Gyroscopes are frequently used in physics lecture demonstrations and in laboratory activities to teach students about rotational dynamics, namely, angular momentum and torque. Use of these powerful concepts makes it difficult for students to fully comprehend the mechanism that keeps the gyroscope from falling under the force of gravity. The…

Algodoo (http://www.algodoo.com) is a digital sandbox for physics 2D simulations. It allows students and teachers to easily create simulated "scenes" and explore physics through a user-friendly and visually attractive interface. In this paper, we present different ways in which students and teachers can use Algodoo to visualize and solve…

This is not a treatise on optics or the index of refraction. It is merely a demonstration that will surprise and engage many of your students. We have all put a pencil in a beaker of water and observed how it appears to bend. Not so much fun or engaging, is it? Why not illustrate this optical effect by taking your students spearfishing?…

Dark matter makes up most of the matter in the universe but very little of a standard introductory physics curriculum. Here we present our construction and use of a spandex sheet-style gravity simulator to qualitatively demonstrate two aspects of modern physics related to dark matter. First, we describe an activity in which students explore the…

Over the past two years, the AAPT/ComPADRE staff and the Open Source Physics group have published the second edition of "Physlet Physics" and "Physlet Quantum Physics," delivered as interactive web pages on AAPT/ComPADRE and as free eBooks available through iTunes and Google Play. These two websites, and their associated books,…

The leading theory for the origin of the Moon is the giant impact hypothesis, in which the Moon was formed out of the debris left over from the collision of a Mars sized body with the Earth. Soon after its formation, the orbit of the Moon may have been very different than it is today. We have simulated the phases of the Moon in a model for its…