Science and Engineering

Science founds Engineering  Every scientific discovery can potentially be used in engineering  Engineers use the scientific laws to:  Invent and design tools and products  Estimate the time and amount of materials needed  Organize the process of construction  Estimate the durability, performance and lifetime of their inventions

Ex.1: Photovoltaic Effect and Solar panels  The Photoelectric Effect (or photoelectric phenomemon) was first observed by Alexandre Becquerel (1839)  It was later recorded by Heinrich Hertz (1887)  The effect is also known as the Hertz Effect  Albert Einstein was first to explain the workings of the effect and describe it mathematically  Bell Labs were first to produce a photovoltaic semiconductor (1954)

Ex.2. Semiconduction effect and digital electronic circuits  Elements such as carbon and silicon are known as semiconductors  current will pass through these materials but under resistance.  A semiconductor diode consists of two layers of material (and a gap between them)  A material with empty electron holes  A material with almost free electrons  This technology replaced triode bulbs

Ex.3: thermodynamics and refrigeration  Thermodynamics was revolutionized in the late 19th century  succeeding a revolution in laws of gasses  The theory defined thermodynamic processes  The processes could be combined to form cycles  P-V diagrams  This made possible the design of  Internal combustion engines  Vapor-compression refrigerators

Ex.4: thermodynamics and absorption-based refrigeration  Absorption refrigeration is based on two important phenomena  Some hydrophile gases such as ammonia can be separated from the water-based solution by heating up the solution  The same gases (ammonia) cool down (absorb heat) when they are recombined with the water  Absorption cycle  You let the gas ammonia “condense”, i.e. cool off by the environment