Floating and sinking might be common phenomena, encountered on a daily basis, but still represent conceptually complex scientific topics. Research has shown that most students have certain experiences and their own "theories" that explain why objects sink or float. Unfortunately, many of these "theories" are either misconceptions or are valid only…

Since long time ago, many authors advocated for more presence of physics history in physics teaching and learning in order to give students a better vision of the "nature of science", in other words, to let them learn not only established physics knowledge but also the ways of how physicists managed to get that knowledge. Generally,…

How do siphons work? Some see atmospheric pressure, explicitly or implicitly, as a crucial factor in siphon action. Others explain that a siphon works due to a difference of water weights in unequal arms. According to the latter view, siphon action is analogous to the action of a pulley or to the behaviour of a chain that is moving over a tube. In…

The phenomenon of weightlessness is known to students thanks to videos of amazing things astronauts do in spaceships orbiting the Earth. In this article we propose two hands-on activities which give students opportunities to infer by themselves the absence of buoyant force in a gravity accelerated system. The system is a free-falling or vertically…