Oblique angle collisions of two penny coins on a smooth, horizontal surface were filmed with a video camera to investigate the physics of the collision process. If one of the coins is initially at rest, then the two coins emerge approximately at right angles, as commonly observed in billiard ball collisions and in puck collisions on an air table.…

Measurements and calculations are presented showing how the trajectory of an object sliding across an inclined plane varies with the launch and incline angles. The trajectory depends on the magnitude and direction of the sliding friction force. The experiment is easy to set up, can be analysed using a video camera, and would be suitable for a…

Points near the top end of a falling rod hinged at its bottom end can fall faster than g. If a rod falls on a frictionless surface then the bottom end slides backwards and the centre of mass falls vertically with acceleration less than g. The effect was simulated by mounting a rod on wheels and filming the result with a video camera. The…

We have developed a stereo vision system for observing real objects for experimental physics demonstration. The stereo vision observes objects from two different points of view. An observer can identify the distance and velocity of an object based on at least two different points of view. This paper demonstrates our comprehensive observation in a…

Since the vibration of a single pendulum is very periodic, measuring its period is a very interesting topic. When students are asked to measure the period of a single vibration, they start and stop the stopwatch when the pendulum reaches the top point as a reference point. In this paper, we try to show that the error can be reduced more by using…

Online video experiments are a promising educational technology tool for science laboratory classes. In order to find optimal instructional designs and scenarios for using online video experiments, we need to study learners' experiences. This work describes implementation of an online interactive video experiment at the undergraduate introductory…

The momentum is often used to analyse the dynamics of the motion of an experimental interaction between objects. Meanwhile, the interaction force tends to be challenging to observe and obtain. In this study, a simple video-assisted experiment was used to observe the interaction forces during the interaction of two magnetic objects. The interaction…

The toppling motion of falling chimney stacks has been the subject of a number of studies which address the interesting phenomenon that brick chimneys usually break well before they hit the ground. Modern concrete chimneys, and wind generator towers, however, are strong enough to topple without breaking and many videos of their destruction are…

The image of free-falling bar has been recorded to study the effect of the motion on its observed length. This moving bar image is analysed using the Tracker software to determine its length and the end bar's position. An elongated appearance of the bar has been observed with movement. This effect relies on the speed and the exposure time during…

Granular flows appear frequently in the natural world and in civil engineering applications. These flows can exhibit features which are surprising and counter-intuitive and are often used to test the limits of the classical continuum approximation for modelling of fluid flows. An important sub-class of the granular flows are the gravity-driven…

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…

The first of the two postulates of relativity states that the laws of physics are the same in all inertial reference frames. Often it is assumed that the postulates are mainly concerned with objects moving at a significant fraction of the speed of light. However, the postulates are applicable at all speeds from a snail to a photon. To practically…

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…

In early January 2018, after days of subfreezing temperatures, a 20 m waterfall became mostly frozen with supercooled water pouring over the top of the frozen parts of the fall. A video was taken of the waterfalls and supercooled turbulent water flowing on the frozen surface as it turned into frazil ice right before our eyes. Frazil ice consists…

A solid ball placed on a rotating turntable is known to roll slowly around a circular path, at a speed 3.5 times slower than the turnable itself. If the ball is located in a straight track across a diameter of the turntable, then it accelerates rapidly to the edge. Both effects were filmed in slow motion using a video camera and a cake decoration…