The symbols Δt and ΔT (spoken as "delta T") are commonly used in a variety of contexts.
Time
*
ΔT (timekeeping)
In precise timekeeping, Δ''T'' (Delta ''T'', delta-''T'', delta''T'', or D''T'') is a measure of the cumulative effect of the departure of the Earth's rotation period from the fixed-length day of International Atomic Time (86,400 second ...
the difference between two time scales, Universal Time and Terrestrial Time, which results from a drift in the length of a day
* The interval of time used in determining
velocity
Velocity is a measurement of speed in a certain direction of motion. It is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of physical objects. Velocity is a vector (geometry), vector Physical q ...
* The increment between
successive nerve impulses
Temperature
* To mean a difference in
temperature
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...
including
thermodynamic temperature
Thermodynamic temperature, also known as absolute temperature, is a physical quantity which measures temperature starting from absolute zero, the point at which particles have minimal thermal motion.
Thermodynamic temperature is typically expres ...
, may occur in
** Discussions of
climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
** Discussions of
heat transfer
Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, ...
** Discussions of the effects of
thermal gradients
See also
*
Delta time (disambiguation) Delta time can mean:
* ΔT (timekeeping), the time difference between Universal Time and Terrestrial Time.
* Delta timing, a technique used in graphics programming.
See also
* ΔT (disambiguation)
The symbols Δt and ΔT (spoken as "delta T") a ...
*
Finite difference
A finite difference is a mathematical expression of the form . Finite differences (or the associated difference quotients) are often used as approximations of derivatives, such as in numerical differentiation.
The difference operator, commonly d ...
for the mathematics of the ''Δ'' operator
*
Delta (letter)
Delta ( ; uppercase Δ, lowercase δ; , ''délta'', ) is the fourth letter of the Greek alphabet. In the system of Greek numerals, it has a value of four. It was derived from the Phoenician alphabet, Phoenician letter Dalet (letter), dalet 𐤃. ...
for the Greek letter Δ
*
∂
The character ∂ (Unicode: U+2202) is a stylized cursive '' d'' mainly used as a mathematical symbol, usually to denote a partial derivative such as / (read as "the partial derivative of ''z'' with respect to ''x''"). It is also used for boundar ...
for the mathematical symbol used in the notation "∂T"
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