Floating Hourglass Puzzle: famous physics puzzle- why does the hourglass not start rising right away? The glass only ascends after about half of the sand has transferred to the lower bulb. The hourglass is a normal glass timer, it is submersed in plain water, and the main tube has an inner diameter which is at least 2mm larger than the diameter of the glass. A simple physics property of the hourglass changes and explains this behavior. I'll post the answer in a few days. ANSWER: As the sand moves from top to bottom the center of mass of the glass changes. Initially the glass is top heavy and wedges against the walls of the cylinder where friction holds it down. Thanks for all the thoughtful and creative comments! ➡️ Follow the link in my profile for info on where to get a version of this physics puzzle and many of the amazing items featured here on @physicsfun #physics #physicstoy #physicspuzzle #puzzle #buoyancy #hourglass #float #gravity #torque #force #friction #science #scienceisawesome #floatinghourglass
Balancing Butterflies: A box set of ten reproductions of Victorian-era illustrations on card stock of butterflies, dragonflies, and moths. Weights under the wings create a center of mass directly below the head of each bug, providing a point of stable equilibrium that will allow the insect to balance on the tip of a pencil! Produced in the 1990s by the Franz-Josef Holler company in Munich, Germany and sadly out of print at this time. ➡️ Follow the link in my profile for info on how to make this toy and where to find many of the items featured here on @physicsfun #equilibrium #centerofmass #physics #physicstoy #balance #balancebird #rotationalinertia #science #scienceisawesome #stableequilibrium
Não se esqueçam de consultar os materiais necessários para a preparação do Exame Nacional de Física e Química A 2016!
Bom estudo! Estamos na reta final!