Physical compression is the result of the subjection of a material to compressive stress, resulting in reduction of volume. Compressive stress is the stress applied to materials resulting in their compaction (decrease of volume The volume of any solid plasma vacuum or theoretical object is how much three- Dimensional space it occupies often quantified numerically The opposite of compression is tension. In Physics String Tension is the magnitude of the pulling force exerted by a string cable chain or similar object on another object

## Explanation

Compression has many implications in material science, physics and structural engineering, for compression yields noticeable amounts of stress and tension. Materials Science or Materials Engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of Science and Physics (Greek Physis - φύσις in everyday terms is the Science of Matter and its motion. Structural engineering is a field of Engineering dealing with the analysis and design of Structures that support or resist loads Structural engineering is Stress is a measure of the average amount of Force exerted per unit Area. In Physics String Tension is the magnitude of the pulling force exerted by a string cable chain or similar object on another object

By inducing compression, mechanical properties such as compressive strength or modulus of elasticity, can be measured. Compressive strength is the capacity of a Material to withstand axially directed pushing forces An elastic modulus, or modulus of elasticity, is the mathematical description of an object or substance's tendency to be deformed elastically (i Scientists may utilize press machines to induce compression. A scientist, in the broadest sense refers to any person that engages in a systematic activity to acquire Knowledge or an individual that engages in such practices

## In engines

### Internal combustion engine

In internal combustion engines it is a necessary condition of economy to compress the explosive mixture before it is ignited: in the Otto cycle, for instance, the second stroke of the piston effects the compression of the charge which has been drawn into the cylinder by the first forward stroke. The internal combustion engine is an engine in which the Combustion of Fuel and an Oxidizer (typically air occurs in a confined space called a Today Internal combustion engines in cars, Trucks motorcycles aircraft construction machinery and many others most commonly use a four-stroke cycle.

### Steam engines

The term is applied to the arrangement by which the exhaust valve of a steam engine is made to close, shutting a portion of the exhaust steam in the cylinder, before the stroke of the piston is quite complete. A steam engine is a Heat engine that performs Mechanical work using Steam as its Working fluid. A cylinder is the central working part of a Reciprocating engine, the space in which a Piston travels This steam being compressed as the stroke is completed, a cushion is formed against which the piston does work while its velocity is being rapidly reduced, and thus the stresses in the mechanism due to the inertia of the reciprocating parts are lessened. A piston is a component of Reciprocating engines Pumps and Gas compressors It is located in a cylinder and is made gas-tight by Piston This compression, moreover, obviates the shock which would otherwise be caused by the admission of the fresh steam for the return stroke.