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A helix (plural: helices) is a twisted shape like a spring, screw or a spiral staircase. Helices are important in biology, as DNA is helical and many proteins have helical substructures, known as alpha helices.

Right-handed and left-handed helices and be distinguished from each other. If you move along a helix in the direction of your right hand's thumb, and the helix turns in the direction of your right hand's fingers, then it's a right-handed helix, otherwise a left-handed one. Another way to visualize this distinction: picture the helix vertical; if the front strands move from the lower left to the upper right, then it is a right-handed helix. Note that handedness (or chirality) is a property of the helix, not of the perspective: you can turn a right-handed helix around and it's still right-handed.

Most screws are right-handed helices. The alpha helix in biology as well as the A and B forms of DNA are also right-handed helices. The Z form of DNA is left-handed.

The pitch of a helix is the length of one complete helix turn, measured along the helix axis.

In mathematics, a helix is a curve in 3-dimensional space. The following three equations in rectangular coordinates define a helix:

x = cos t

y = sin t

z = t

Here t is a real parameter. As t increases, the point (x,y,z) traces a right-handed helix of pitch 2 πOr pi with a lower-case p . minuscule, or lower-case, pi The mathematical constant (written as pi when the Greek letter is not available) is ubiquitous in mathematics and physics. In Euclidean plane geometry, π may be defined as either the ratio of a c about the z-axis, in a right-handed coordinate system.

In cylindrical coordinates (r, θ, h), the same helix is described by:

r = 1

θ = h

Except for rotationThis article is about rotation as a movement of a physical body. For other meanings, see rotation (disambiguation). Rotation is the movement of a body in such a way that any given point of that body remains at a constant distance from some other fixed pois, translationEuclidean geometry In Euclidean geometry, translation is a transformation of Euclidean space which moves every point by a fixed distance in the same direction. It can also be interpreted as the addition of a constant vector to every point, or as shiftings, and changes of scale, all right-handed helices are equivalent to the helix defined above.

In musicMusic often an art/ entertainment, is a total social fact whose definitions vary according to era and culture," according to Jean Molino. 1 It is often contrasted with noise. According to musicologist Jean-Jacques Nattiez: "The border between music and no pitch spaceIn music pitch space is pitch relations, ie nearness or farness, represented through geometric models, most often multi dimensional, how near or far pitches are from each other. Cognitive psychologists including Longuet-Higgins (1978) and Shepard (1982), is often modeled with helixes or double helixes, most often extending out of a circle such as the circle of fifthsIn music theory, the circle of fifths is a sequence encompassing all of the notes in the equally tempered chromatic scale. Starting on any note and repeatedly ascending by the musical interval of a perfect fifth, one will eventually land on the same note,, so as to represent octave equivalency.