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Submarines submerge and surface by changing the average density of the hull.
The length of the metal frameworks of bridges change when the temperature changes.
Jamestown, founded in 1607, was the first permanent English settlement on the east coast of North America.
Thermal power stations convert energy released during the combustion of fossil fuels or renewable resources into electricity.
During its orbit around the Earth, the visibility of the Moon's illuminated part constantly changes.
Farming techniques evolved with the development of human civilisation in the Middle Ages and the Modern Age.
The suspension bridge that stretches above the strait between San Francisco Bay and the Pacific Ocean was opened in 1937.
The Olympic Games, held in the town every 4th year after 776 BC made it one of the centres of ancient Greece.
Oxygen carrier protein in our red blood cells.
An air conditioner cools the air inside by drawing heat away and releasing it outside.
A crystalline allotrope of carbon which was discovered at the end of the 1980s.
This animation demonstrates the mechanism and operation of record players.
A polynucleotid made up of phosphoric acid, ribose, and nucleobases (cytosine, uracil, adenine and guanine).
Addition is a reaction in which the molecules of two or more substances unite without the formation of a by-product.
The legendary M61 class locomotives of the Hungarian State Railways were manufactured by Nohab.
Limestone is a widely and diversely used material.
The device designed to carry out executions more humanely than before was named after a French doctor.
During the substitution reaction the hydrogen atoms of methane are substituted with chlorine atoms, the by-product is hydrogen chloride.
Fatty acid molecules consist of a polar head and a non-polar tail, therefore they are suitable for removing fat stains.
Machinery that pumps crude oil to the surface