# Logarithmic scale

logarithmiclogarithmic unitLogLogarithmic graph paperlogarithmic unitslog compressionlog-scaleLogarithmlogarithmic formlogarithmic in size
A logarithmic scale is a nonlinear scale used for a large range of positive multiples of some quantity.wikipedia
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### PH

pH levelneutralpH value
Common uses include earthquake strength, sound loudness, light intensity, and pH of solutions.
The pH scale is logarithmic and inversely indicates the concentration of hydrogen ions in the solution (a lower pH indicates a higher concentration of hydrogen ions).

### Slide rule

slide rulescircular slide ruleslide-rule
Logarithmic scales are also used in slide rules for multiplying or dividing numbers by adding or subtracting lengths on the scales. A slide rule has logarithmic scales, and nomograms often employ logarithmic scales.
In its most basic form, the slide rule uses two logarithmic scales to allow rapid multiplication and division of numbers.

### Cent (music)

centscentdecitone
Logarithmic frequency quantities are used in electronics (decade, octave) and for music pitch intervals (octave, semitone, cent, etc.).
The cent is a logarithmic unit of measure used for musical intervals.

### Weber–Fechner law

Weber's lawWeber-Fechner lawis non-linear
Some of our senses operate in a logarithmic fashion (Weber–Fechner law), which makes logarithmic scales for these input quantities especially appropriate.
The relationship between stimulus and perception is logarithmic.

### Logarithmic timeline

logarithmic scale
A logarithmic timeline is a timeline laid out according to a logarithmic scale.

### Palermo Technical Impact Hazard Scale

Palermo Technical ScalePalermo scalePalermo rating
The Palermo Technical Impact Hazard Scale is a logarithmic scale used by astronomers to rate the potential hazard of impact of a near-earth object (NEO).

### Neper

nepers10centineper
Examples of logarithmic units include units of data storage capacity (bit, byte), of information and information entropy (nat, shannon, ban), signal level (decibel, bel, neper).
Like the decibel, the neper is a unit in a logarithmic scale.

### Logit

log-oddslogit functionlogit transformation
The choice of base corresponds to the choice of logarithmic unit for the value: base 2 corresponds to a shannon, base e to a nat, and base 10 to a hartley; these units are particularly used in information-theoretic interpretations.

### Apparent magnitude

apparent visual magnitudemagnitudevisual magnitude
The magnitude scale is reverse logarithmic such that having a magnitude 5 higher than another object's means that it is 100 times dimmer.

### F-number

aperturefocal ratiof-stop
Ignoring the f-number markings, the f-stops make a logarithmic scale of exposure intensity.

### Entropy

entropicentropicallyspecific entropy
Specifically, entropy is a logarithmic measure of the number of states with significant probability of being occupied:

### Level of measurement

quantitativelevels of measurementscale
A logarithmic scale is a nonlinear scale used for a large range of positive multiples of some quantity.

### Log–log plot

log-log plotlog-log graphlog-log
If both the vertical and horizontal axes of a plot are scaled logarithmically, the plot is referred to as a log–log plot.
In science and engineering, a log–log graph or log–log plot is a two-dimensional graph of numerical data that uses logarithmic scales on both the horizontal and vertical axes.

### Logarithm

logarithmsloglogarithmic function
A logarithmic unit is a unit that can be used to express a quantity (physical or mathematical) on a logarithmic scale, that is, as being proportional to the value of a logarithm function applied to the ratio of the quantity and a reference quantity of the same type.
Logarithmic scales reduce wide-ranging quantities to tiny scopes.

### Linear scale

bar scalescale barscales
It is based on orders of magnitude, rather than a standard linear scale, so the value represented by each equidistant mark on the scale is the value at the previous mark multiplied by a constant.

### Moment magnitude scale

moment magnitudeM w magnitude
As with the Richter scale, an increase of one step on the logarithmic scale of moment magnitude corresponds to a 10 1.5 ≈ 32 times increase in the amount of energy released, and an increase of two steps corresponds to a 10 3 = 1000 times increase in energy.

### Nomogram

nomogramsnomographnomography
A slide rule has logarithmic scales, and nomograms often employ logarithmic scales.
These scales may be linear, logarithmic, or have some more complex relationship.

### Hartley (unit)

hartleybanBan (unit)
Examples of logarithmic units include units of data storage capacity (bit, byte), of information and information entropy (nat, shannon, ban), signal level (decibel, bel, neper).
The hartley (symbol Hart), also called a ban, or a dit (short for decimal digit), is a logarithmic unit which measures information or entropy, based on base 10 logarithms and powers of 10, rather than the powers of 2 and base 2 logarithms which define the bit, or shannon.

### Decibel

dBdecibelsbel
Examples of logarithmic units include units of data storage capacity (bit, byte), of information and information entropy (nat, shannon, ban), signal level (decibel, bel, neper).
The decibel (symbol: dB) is a unit of measurement used to express the ratio of one value of a power or field quantity to another, on a logarithmic scale, the logarithmic quantity being called the power level or field level, respectively.

### Grain size

particle sizeKrumbein phi scaleParticle size (grain size)

Logarithmic frequency quantities are used in electronics (decade, octave) and for music pitch intervals (octave, semitone, cent, etc.).
One decade (symbol dec ) is a unit for measuring frequency ratios on a logarithmic scale, with one decade corresponding to a ratio of 10 between two frequencies (an order of magnitude difference).

### One-third octave

A one-third octave is a logarithmic unit of frequency ratio equal to either one third of an octave or one tenth of a decade.

### Interval (music)

intervalintervalsmusical interval
Logarithmic frequency quantities are used in electronics (decade, octave) and for music pitch intervals (octave, semitone, cent, etc.).
The cent is a logarithmic unit of measurement.

### Level (logarithmic quantity)

levellogarithmic measurefrequency level
In science and engineering, a power level and a field level (also called a root-power level) are logarithmic measures of certain quantities referenced to a standard reference value of the same type.

### Graph paper

Grid papercoordinate paperlog paper
Before the advent of computer graphics, logarithmic graph paper was a commonly used scientific tool.