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