Traditional stilts have been known in many countries in Asia and Africa and are generally used as toys. The design is very simple, but their use is very difficult. Performers have to train intensively to control their stability so they can walk using them. An interesting challenge is what kind of physical formulation controls the stability of traditional stilts. In this paper, we report a simple physical formulation to explain the mechanics of traditional stilts. The traditional stilts can be considered as an alternating inverted pendulum stabilized by hand and a physical pendulum pivoting at the hand. Experiments were also carried out using a stilt made of bamboo rods. We identified a number of parameters that control the stability of the stilts. This type of research can become a topic for research-based learning at universities.

We divide the solenoid into ‘seen arc portion’ and ‘unseen arc portion’ when observed from the point of measurement. The magnitudes of fields produced by the two portions are the same but in opposite directions. This is the reason why the magnetic field outside an ideal solenoid is zero. Interestingly, the magnitude of the field produced by each portion follows the change of angle of view to the outer boundary of the solenoid when observed from the point of measurement. We have also distributed questionaries to students to get feedback on whether the topics discussed in this paper are easy for undergraduate students to understand.

We developed a simple physics model to explain the profile of the rope played in the rope jumping game.  Firstly, we derived a second order non-linear differential equation to explain the rope motion. Analytical solutions can be obtained if the displacement of all points along the rope is small. For arbitrary deviations, a numerical solution must be employed, and at the present paper, we used a simple excel-visual basic program. We found that the profiles of the simulation results is very similar to the real profile which can be observed in a number of sources on the internet. A critical value separating the condition where the rope length remains unchange and the condition when the rope changes suddenly with rw2/T was identified. A scaling relationship was also identified in the changing region with the critical exponent of -0.31. The existence of the critical point and the critical exponent in the changing region informs that the change in the rope profile resembles the phase transition phenomenon

When the road is wet (there is a water layer on the road surface), the road marks become blurred and drivers are distracted. We discuss the contributing processes and identify which processes are dominant to the occurrence of this phenomenon. Modelling and a simple experiment demonstrate that the dominant processes are: (a) refraction of light by the water layer that reduces the beam angle of the light that enters the driver’s eyes, (b) reflection of light in the water layer, and (c) the glare.