Surface tension

Surfaces tension – The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension. The molecules at the surface do not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the surface. This forms a surface “film” which makes it more difficult to move an object through the surface than to move it when it is completely submersed. Surface Tension Bascic Concepts – Flash animation “floating” – Only objects lighter than water can float. This insects is prevented from sinking because of surface … Continue reading Surface tension

Statue of Liberty

In addition to being a great inspiration and a symbol of freedom and life in a new land, the Statue of Liberty is an example of an engineering challenge in the late 1800s. The lady with the lamp Video: Modern Marvels The Statue of Liberty (45 minutes) describes the engineering that went into the design, construction and restoration over more than 100 years. The Statue of Liberty stands on a small island in New York harbor on a specially-build pedestal. The statue was a gift from the people of France. The sculpture is so big that the French artist Frederic … Continue reading Statue of Liberty

Cat’s Eye: Reflective Road Marker

Cat’s Eye: Reflective Road Marker "The Cat’s Eye invented in 1933 features reflective glass spheres set inside a rubber and cast-iron housing. Each unit is complex and dynamic, its various materials engineered to serve a variety of clever functions. The metal part of the housing protects the device while creating an audible sound when a car passes over, like Botts’ Dots. Meanwhile, a fixed rubber wiper clears off the glass when it is pushed under the road. The Cat’s Eye is also retroflective, meaning: it redirects light back toward its source with minimum scattering, optimizing visibility for cars in motion." … Continue reading Cat’s Eye: Reflective Road Marker