text: In meteorology, diurnal temperature variation is the variation between a high temperature and a low temperature that occurs during the same day.

text: In

text: meteorology

text: diurnal

text: temperature

text: variation

text: is

text: the

text: variation

text: between

text: high

text: temperature

text: and

text: low

text: temperature

text: that

text: occurs

text: during

text: the

text: same

text: day

text:
The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process.<ref name="doi10.1146/annurev-astro-081913-040012"></ref> It is by far the most important source of energy for life on Earth. Its diameter is about 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System.
About three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.

text: The

text: Sun

text: is

text: the

text: star

text: at

text: the

text: center

text: of

text: the

text: Solar

text: System

text: It

text: is

text: nearly

text: perfect

text: sphere

text: of

text: hot

text: plasma

text: with

text: internal

text: convective

text: motion

text: that

text: generates

text: magnetic

text: field

text: via

text: dynamo

text: process.<ref

text: It

text: is

text: by

text: far

text: the

text: most

text: important

text: source

text: of

text: energy

text: for

text: life

text: on

text: Earth

text: Its

text: diameter

text: is

text: about

text: times

text: that

text: of

text: Earth

text: and

text: its

text: mass

text: is

text: about

text: times

text: that

text: of

text: Earth

text: accounting

text: for

text: about

text: of

text: the

text: total

text: mass

text: of

text: the

text: Solar

text: System

text: About

text: three

text: quarters

text: of

text: the

text: Sun

text: 's

text: mass

text: consists

text: of

text: hydrogen

text: the

text: rest

text: is

text: mostly

text: helium

text: with

text: much

text: smaller

text: quantities

text: of

text: heavier

text: elements

text: including

text: oxygen

text: carbon

text: neon

text: and

text: iron

text: In physics, energy is the property that must be transferred to an object in order to perform work on  or to heat  the object, and can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the energy transferred to an object by the mechanical work of moving it a distance of 1 metre against a force of 1 newton.

text: In

text: physics

text: energy

text: is

text: the

text: property

text: that

text: must

text: be

text: transferred

text: to

text: an

text: object

text: in

text: order

text: to

text: perform

text: work

text: on

text: or

text: to

text: heat

text: the

text: object

text: and

text: can

text: be

text: converted

text: in

text: form

text: but

text: not

text: created

text: or

text: destroyed

text: The

text: SI

text: unit

text: of

text: energy

text: is

text: the

text: joule

text: which

text: is

text: the

text: energy

text: transferred

text: to

text: an

text: object

text: by

text: the

text: mechanical

text: work

text: of

text: moving

text: it

text: distance

text: of

text: metre

text: against

text: force

text: of

text: newton

text: Fahrenheit is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit (16861736), after whom the scale is named. It uses the degree Fahrenheit (symbol °F) as the unit. There exist several accounts of how he originally defined his scale. The lower defining point, 0 °F, was established as the temperature of a solution of brine made from equal parts of ice and salt. Further limits were established as the melting point of ice (32 °F) and his best estimate of the average human body temperature (96 °F, about 2.6 °F less than the modern value due to a later redefinition of the scale). The scale is now usually defined by two fixed points: the temperature at which water freezes into ice is defined as 32 °F, and the boiling point of water is defined to be 212 °F, a 180 °F separation, as defined at sea level and standard atmospheric pressure.

text: Fahrenheit

text: is

text: temperature

text: scale

text: based

text: on

text: one

text: proposed

text: in

text: by

text: the

text: physicist

text: Daniel

text: Gabriel

text: Fahrenheit

text: after

text: whom

text: the

text: scale

text: is

text: named

text: It

text: uses

text: the

text: degree

text: Fahrenheit

text: symbol

text: as

text: the

text: unit

text: There

text: exist

text: several

text: accounts

text: of

text: how

text: he

text: originally

text: defined

text: his

text: scale

text: The

text: lower

text: defining

text: point

text: was

text: established

text: as

text: the

text: temperature

text: of

text: solution

text: of

text: brine

text: made

text: from

text: equal

text: parts

text: of

text: ice

text: and

text: salt

text: Further

text: limits

text: were

text: established

text: as

text: the

text: melting

text: point

text: of

text: ice

text: and

text: his

text: best

text: estimate

text: of

text: the

text: average

text: human

text: body

text: temperature

text: about

text: less

text: than

text: the

text: modern

text: value

text: due

text: to

text: later

text: redefinition

text: of

text: the

text: scale

text: The

text: scale

text: is

text: now

text: usually

text: defined

text: by

text: two

text: fixed

text: points

text: the

text: temperature

text: at

text: which

text: water

text: freezes

text: into

text: ice

text: is

text: defined

text: as

text: and

text: the

text: boiling

text: point

text: of

text: water

text: is

text: defined

text: to

text: be

text: separation

text: as

text: defined

text: at

text: sea

text: level

text: and

text: standard

text: atmospheric

text: pressure

text: X-radiation (composed of X-rays) is a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3×10 Hz to 3×10 Hz) and energies in the range 100 eV to 100 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to with terms meaning Röntgen radiation, after the German (German-Dutch to be precise) scientist Wilhelm Röntgen, who usually is credited as its discoverer, and who had named it "X-radiation" to signify an unknown type of radiation. Spelling of "X-ray(s)" in the English language includes the variants "x-ray(s)", "xray(s)", and "X ray(s)".

text: radiation

text: composed

text: of

text: rays

text: is

text: form

text: of

text: electromagnetic

text: radiation

text: Most

text: rays

text: have

text: wavelength

text: ranging

text: from

text: to

text: nanometers

text: corresponding

text: to

text: frequencies

text: in

text: the

text: range

text: petahertz

text: to

text: exahertz

text: Hz

text: to

text: Hz

text: and

text: energies

text: in

text: the

text: range

text: eV

text: to

text: keV.

text: ray

text: wavelengths

text: are

text: shorter

text: than

text: those

text: of

text: UV

text: rays

text: and

text: typically

text: longer

text: than

text: those

text: of

text: gamma

text: rays

text: In

text: many

text: languages

text: radiation

text: is

text: referred

text: to

text: with

text: terms

text: meaning

text: Röntgen

text: radiation

text: after

text: the

text: German

text: German

text: Dutch

text: to

text: be

text: precise

text: scientist

text: Wilhelm

text: Röntgen

text: who

text: usually

text: is

text: credited

text: as

text: its

text: discoverer

text: and

text: who

text: had

text: named

text: it

text: radiation

text: to

text: signify

text: an

text: unknown

text: type

text: of

text: radiation

text: Spelling

text: of

text: ray(s

text: in

text: the

text: English

text: language

text: includes

text: the

text: variants

text: ray(s

text: xray(s

text: and

text: ray(s

text: Life is a characteristic distinguishing physical entities having biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential artificial life as "living". Biology is the primary science concerned with the study of life, although many other sciences are involved.

text: Life

text: is

text: characteristic

text: distinguishing

text: physical

text: entities

text: having

text: biological

text: processes

text: such

text: as

text: signaling

text: and

text: self

text: sustaining

text: processes

text: from

text: those

text: that

text: do

text: not

text: either

text: because

text: such

text: functions

text: have

text: ceased

text: or

text: because

text: they

text: never

text: had

text: such

text: functions

text: and

text: are

text: classified

text: as

text: inanimate

text: Various

text: forms

text: of

text: life

text: exist

text: such

text: as

text: plants

text: animals

text: fungi

text: protists

text: archaea

text: and

text: bacteria

text: The

text: criteria

text: can

text: at

text: times

text: be

text: ambiguous

text: and

text: may

text: or

text: may

text: not

text: define

text: viruses

text: viroids

text: or

text: potential

text: artificial

text: life

text: as

text: living

text: Biology

text: is

text: the

text: primary

text: science

text: concerned

text: with

text: the

text: study

text: of

text: life

text: although

text: many

text: other

text: sciences

text: are

text: involved

text: In physics, a wave is an oscillation accompanied by a transfer of energy that travels through a medium (space or mass). Frequency refers to the addition of time. "Wave motion" transfers energy from one point to another, which displace particles of the transmission mediumthat is, with little or no associated mass transport. Waves consist, instead, of oscillations or vibrations (of a physical quantity), around almost fixed locations.

text: In

text: physics

text: wave

text: is

text: an

text: oscillation

text: accompanied

text: by

text: transfer

text: of

text: energy

text: that

text: travels

text: through

text: medium

text: space

text: or

text: mass

text: Frequency

text: refers

text: to

text: the

text: addition

text: of

text: time

text: Wave

text: motion

text: transfers

text: energy

text: from

text: one

text: point

text: to

text: another

text: which

text: displace

text: particles

text: of

text: the

text: transmission

text: mediumthat

text: is

text: with

text: little

text: or

text: no

text: associated

text: mass

text: transport

text: Waves

text: consist

text: instead

text: of

text: oscillations

text: or

text: vibrations

text: of

text: physical

text: quantity

text: around

text: almost

text: fixed

text: locations

text: Earth, otherwise known as the world, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets.

text: Earth

text: otherwise

text: known

text: as

text: the

text: world

text: is

text: the

text: third

text: planet

text: from

text: the

text: Sun

text: and

text: the

text: only

text: object

text: in

text: the

text: Universe

text: known

text: to

text: harbor

text: life

text: It

text: is

text: the

text: densest

text: planet

text: in

text: the

text: Solar

text: System

text: and

text: the

text: largest

text: of

text: the

text: four

text: terrestrial

text: planets

text: Ultraviolet (UV) is an electromagnetic radiation with a wavelength from 10 nm (30 PHz) to 400 nm (750 THz), shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the total light output of the Sun, and is thus present in sunlight. It is also produced by electric arcs and specialized lights such as mercury-vapor lamps, tanning lamps, and black lights. Although it is not considered an ionizing radiation because its photons lack the energy to ionize atoms, long-wavelength ultraviolet radiation can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules.

text: Ultraviolet

text: UV

text: is

text: an

text: electromagnetic

text: radiation

text: with

text: wavelength

text: from

text: nm

text: PHz

text: to

text: nm

text: THz

text: shorter

text: than

text: that

text: of

text: visible

text: light

text: but

text: longer

text: than

text: rays

text: UV

text: radiation

text: constitutes

text: about

text: of

text: the

text: total

text: light

text: output

text: of

text: the

text: Sun

text: and

text: is

text: thus

text: present

text: in

text: sunlight

text: It

text: is

text: also

text: produced

text: by

text: electric

text: arcs

text: and

text: specialized

text: lights

text: such

text: as

text: mercury

text: vapor

text: lamps

text: tanning

text: lamps

text: and

text: black

text: lights

text: Although

text: it

text: is

text: not

text: considered

text: an

text: ionizing

text: radiation

text: because

text: its

text: photons

text: lack

text: the

text: energy

text: to

text: ionize

text: atoms

text: long

text: wavelength

text: ultraviolet

text: radiation

text: can

text: cause

text: chemical

text: reactions

text: and

text: causes

text: many

text: substances

text: to

text: glow

text: or

text: fluoresce

text: Consequently

text: biological

text: effects

text: of

text: UV

text: are

text: greater

text: than

text: simple

text: heating

text: effects

text: and

text: many

text: practical

text: applications

text: of

text: UV

text: radiation

text: derive

text: from

text: its

text: interactions

text: with

text: organic

text: molecules

text: An electric arc or arc discharge is an electrical breakdown of a gas that produces an ongoing electrical discharge. The current through a normally nonconductive medium such as air produces a plasma; the plasma may produce visible light. An arc discharge is characterized by a lower voltage than a glow discharge, and it relies on thermionic emission of electrons from the electrodes supporting the arc. An archaic term is voltaic arc, as used in the phrase "voltaic arc lamp".

text: An

text: electric

text: arc

text: or

text: arc

text: discharge

text: is

text: an

text: electrical

text: breakdown

text: of

text: gas

text: that

text: produces

text: an

text: ongoing

text: electrical

text: discharge

text: The

text: current

text: through

text: normally

text: nonconductive

text: medium

text: such

text: as

text: air

text: produces

text: plasma

text: the

text: plasma

text: may

text: produce

text: visible

text: light

text: An

text: arc

text: discharge

text: is

text: characterized

text: by

text: lower

text: voltage

text: than

text: glow

text: discharge

text: and

text: it

text: relies

text: on

text: thermionic

text: emission

text: of

text: electrons

text: from

text: the

text: electrodes

text: supporting

text: the

text: arc

text: An

text: archaic

text: term

text: is

text: voltaic

text: arc

text: as

text: used

text: in

text: the

text: phrase

text: voltaic

text: arc

text: lamp

text: The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere.

text: The

text: greenhouse

text: effect

text: is

text: the

text: process

text: by

text: which

text: radiation

text: from

text: planet

text: 's

text: atmosphere

text: warms

text: the

text: planet

text: 's

text: surface

text: to

text: temperature

text: above

text: what

text: it

text: would

text: be

text: without

text: its

text: atmosphere

text: In physics, heat is that amount of energy flowing from one body to another spontaneously due to their temperature difference, or by any means other than through work or the transfer of matter. The transfer can be by contact between the source and the destination body, as in conduction; or by radiation between remote bodies; or by conduction and radiation through a thick solid wall; or by way of an intermediate fluid body, as in convective circulation; or by a combination of these.

text: In

text: physics

text: heat

text: is

text: that

text: amount

text: of

text: energy

text: flowing

text: from

text: one

text: body

text: to

text: another

text: spontaneously

text: due

text: to

text: their

text: temperature

text: difference

text: or

text: by

text: any

text: means

text: other

text: than

text: through

text: work

text: or

text: the

text: transfer

text: of

text: matter

text: The

text: transfer

text: can

text: be

text: by

text: contact

text: between

text: the

text: source

text: and

text: the

text: destination

text: body

text: as

text: in

text: conduction

text: or

text: by

text: radiation

text: between

text: remote

text: bodies

text: or

text: by

text: conduction

text: and

text: radiation

text: through

text: thick

text: solid

text: wall

text: or

text: by

text: way

text: of

text: an

text: intermediate

text: fluid

text: body

text: as

text: in

text: convective

text: circulation

text: or

text: by

text: combination

text: of

text: these

text: In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-, and gamma radiation.

text: In

text: physics

text: electromagnetic

text: radiation

text: EM

text: radiation

text: or

text: EMR

text: refers

text: to

text: the

text: waves

text: or

text: their

text: quanta

text: photons

text: of

text: the

text: electromagnetic

text: field

text: propagating

text: radiating

text: through

text: space

text: carrying

text: electromagnetic

text: radiant

text: energy

text: It

text: includes

text: radio

text: waves

text: microwaves

text: infrared

text: visible

text: light

text: ultraviolet

text: X-

text: and

text: gamma

text: radiation

text: A greenhouse (also called a glasshouse, or, if with sufficient heating, a hothouse) is a structure with walls and roof made chiefly of transparent material, such as glass, in which plants requiring regulated climatic conditions are grown. These structures range in size from small sheds to industrial-sized buildings. A miniature greenhouse is known as a cold frame. The interior of a greenhouse exposed to sunlight becomes significantly warmer than the external ambient temperature, protecting its contents in cold weather.

text: greenhouse

text: also

text: called

text: glasshouse

text: or

text: if

text: with

text: sufficient

text: heating

text: hothouse

text: is

text: structure

text: with

text: walls

text: and

text: roof

text: made

text: chiefly

text: of

text: transparent

text: material

text: such

text: as

text: glass

text: in

text: which

text: plants

text: requiring

text: regulated

text: climatic

text: conditions

text: are

text: grown

text: These

text: structures

text: range

text: in

text: size

text: from

text: small

text: sheds

text: to

text: industrial

text: sized

text: buildings

text: miniature

text: greenhouse

text: is

text: known

text: as

text: cold

text: frame

text: The

text: interior

text: of

text: greenhouse

text: exposed

text: to

text: sunlight

text: becomes

text: significantly

text: warmer

text: than

text: the

text: external

text: ambient

text: temperature

text: protecting

text: its

text: contents

text: in

text: cold

text: weather

text: A mercury-vapor lamp is a gas discharge lamp that uses an electric arc through vaporized mercury to produce light. The arc discharge is generally confined to a small fused quartz arc tube mounted within a larger borosilicate glass bulb. The outer bulb may be clear or coated with a phosphor; in either case, the outer bulb provides thermal insulation, protection from the ultraviolet radiation the light produces, and a convenient mounting for the fused quartz arc tube.

text: mercury

text: vapor

text: lamp

text: is

text: gas

text: discharge

text: lamp

text: that

text: uses

text: an

text: electric

text: arc

text: through

text: vaporized

text: mercury

text: to

text: produce

text: light

text: The

text: arc

text: discharge

text: is

text: generally

text: confined

text: to

text: small

text: fused

text: quartz

text: arc

text: tube

text: mounted

text: within

text: larger

text: borosilicate

text: glass

text: bulb

text: The

text: outer

text: bulb

text: may

text: be

text: clear

text: or

text: coated

text: with

text: phosphor

text: in

text: either

text: case

text: the

text: outer

text: bulb

text: provides

text: thermal

text: insulation

text: protection

text: from

text: the

text: ultraviolet

text: radiation

text: the

text: light

text: produces

text: and

text: convenient

text: mounting

text: for

text: the

text: fused

text: quartz

text: arc

text: tube

text: Meteorology is the interdisciplinary scientific study of the atmosphere. The study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It wasn't until after the elucidation of the laws of physics and, more particularly, the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved.

text: Meteorology

text: is

text: the

text: interdisciplinary

text: scientific

text: study

text: of

text: the

text: atmosphere

text: The

text: study

text: of

text: meteorology

text: dates

text: back

text: millennia

text: though

text: significant

text: progress

text: in

text: meteorology

text: did

text: not

text: occur

text: until

text: the

text: century

text: The

text: century

text: saw

text: modest

text: progress

text: in

text: the

text: field

text: after

text: weather

text: observation

text: networks

text: were

text: formed

text: across

text: broad

text: regions

text: Prior

text: attempts

text: at

text: prediction

text: of

text: weather

text: depended

text: on

text: historical

text: data

text: It

text: was

text: n't

text: until

text: after

text: the

text: elucidation

text: of

text: the

text: laws

text: of

text: physics

text: and

text: more

text: particularly

text: the

text: development

text: of

text: the

text: computer

text: allowing

text: for

text: the

text: automated

text: solution

text: of

text: great

text: many

text: equations

text: that

text: model

text: the

text: weather

text: in

text: the

text: latter

text: half

text: of

text: the

text: century

text: that

text: significant

text: breakthroughs

text: in

text: weather

text: forecasting

text: were

text: achieved

text:
In physics, the wavelength of a sinusoidal wave is the spatial period of the wavethe distance over which the wave's shape repeats,
and thus the inverse of the spatial frequency. It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns.
Wavelength is commonly designated by the Greek letter "lambda" (). The concept can also be applied to periodic waves of non-sinusoidal shape.
The term "wavelength" is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.

text: In

text: physics

text: the

text: wavelength

text: of

text: sinusoidal

text: wave

text: is

text: the

text: spatial

text: period

text: of

text: the

text: wavethe

text: distance

text: over

text: which

text: the

text: wave

text: 's

text: shape

text: repeats

text: and

text: thus

text: the

text: inverse

text: of

text: the

text: spatial

text: frequency

text: It

text: is

text: usually

text: determined

text: by

text: considering

text: the

text: distance

text: between

text: consecutive

text: corresponding

text: points

text: of

text: the

text: same

text: phase

text: such

text: as

text: crests

text: troughs

text: or

text: zero

text: crossings

text: and

text: is

text: characteristic

text: of

text: both

text: traveling

text: waves

text: and

text: standing

text: waves

text: as

text: well

text: as

text: other

text: spatial

text: wave

text: patterns

text: Wavelength

text: is

text: commonly

text: designated

text: by

text: the

text: Greek

text: letter

text: lambda

text: The

text: concept

text: can

text: also

text: be

text: applied

text: to

text: periodic

text: waves

text: of

text: non

text: sinusoidal

text: shape

text: The

text: term

text: wavelength

text: is

text: also

text: sometimes

text: applied

text: to

text: modulated

text: waves

text: and

text: to

text: the

text: sinusoidal

text: envelopes

text: of

text: modulated

text: waves

text: or

text: waves

text: formed

text: by

text: interference

text: of

text: several

text: sinusoids

text: Night or nighttime ("sp." night-time or night time) is the period of time between the sunset and the sunrise when the Sun is below the horizon.

text: Night

text: or

text: nighttime

text: sp

text: night

text: time

text: or

text: night

text: time

text: is

text: the

text: period

text: of

text: time

text: between

text: the

text: sunset

text: and

text: the

text: sunrise

text: when

text: the

text: Sun

text: is

text: below

text: the

text: horizon

text: A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes may occur.

text: chemical

text: reaction

text: is

text: process

text: that

text: leads

text: to

text: the

text: transformation

text: of

text: one

text: set

text: of

text: chemical

text: substances

text: to

text: another

text: Classically

text: chemical

text: reactions

text: encompass

text: changes

text: that

text: only

text: involve

text: the

text: positions

text: of

text: electrons

text: in

text: the

text: forming

text: and

text: breaking

text: of

text: chemical

text: bonds

text: between

text: atoms

text: with

text: no

text: change

text: to

text: the

text: nuclei

text: no

text: change

text: to

text: the

text: elements

text: present

text: and

text: can

text: often

text: be

text: described

text: by

text: chemical

text: equation

text: Nuclear

text: chemistry

text: is

text: sub

text: discipline

text: of

text: chemistry

text: that

text: involves

text: the

text: chemical

text: reactions

text: of

text: unstable

text: and

text: radioactive

text: elements

text: where

text: both

text: electronic

text: and

text: nuclear

text: changes

text: may

text: occur

text: A temperature is an objective comparative measurement of hot or cold. It is measured by a thermometer. Several scales and units exist for measuring temperature, the most common being Celsius (denoted °C; formerly called "centigrade"), Fahrenheit (denoted °F), and, especially in science, Kelvin (denoted K).

text: temperature

text: is

text: an

text: objective

text: comparative

text: measurement

text: of

text: hot

text: or

text: cold

text: It

text: is

text: measured

text: by

text: thermometer

text: Several

text: scales

text: and

text: units

text: exist

text: for

text: measuring

text: temperature

text: the

text: most

text: common

text: being

text: Celsius

text: denoted

text: formerly

text: called

text: centigrade

text: Fahrenheit

text: denoted

text: and

text: especially

text: in

text: science

text: Kelvin

text: denoted

text: The atmosphere of Earth is the layer of gases surrounding the planet Earth that is retained by Earth 's gravity . The atmosphere protects life on Earth by absorbing ultraviolet solar radiation , warming the surface through heat retention ( greenhouse effect ) , and reducing temperature extremes between day and night ( the diurnal temperature variation ) . The common name air ( English pronunciation : / r / ) is given to the atmospheric gases used in breathing and photosynthesis . By volume , dry air contains 78.09 % nitrogen , 20.95 % oxygen , 0.93 % argon , 0.039 % carbon dioxide , and small amounts of other gases . Air also contains a variable amount of water vapor , on average around 1 % at sea level , and 0.4 % over the entire atmosphere . Air content and atmospheric pressure vary at different layers , and air suitable for the survival of terrestrial plants and terrestrial animals is found only in Earth 's troposphere and artificial atmospheres . The atmosphere has a mass of about 5.15 × 1018 kg , three quarters of which is within about 11 km ( 6.8 mi ; 36,000 ft ) of the surface . The atmosphere becomes thinner and thinner with increasing altitude , with no definite boundary between the atmosphere and outer space . The Kármán line , at 100 km ( 62 mi ) , or 1.57 % of Earth 's radius , is often used as the border between the atmosphere and outer space . Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km ( 75 mi ) . Several layers can be distinguished in the atmosphere , based on characteristics such as temperature and composition . The study of Earth 's atmosphere and its processes is called atmospheric science ( aerology ) . Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann .

text: The

text: atmosphere

text: of

text: Earth

text: is

text: the

text: layer

text: of

text: gases

text: surrounding

text: the

text: planet

text: Earth

text: that

text: is

text: retained

text: by

text: Earth

text: 's

text: gravity

text: The

text: atmosphere

text: protects

text: life

text: on

text: Earth

text: by

text: absorbing

text: ultraviolet

text: solar

text: radiation

text: warming

text: the

text: surface

text: through

text: heat

text: retention

text: greenhouse

text: effect

text: and

text: reducing

text: temperature

text: extremes

text: between

text: day

text: and

text: night

text: the

text: diurnal

text: temperature

text: variation

text: The

text: common

text: name

text: air

text: English

text: pronunciation

text: is

text: given

text: to

text: the

text: atmospheric

text: gases

text: used

text: in

text: breathing

text: and

text: photosynthesis

text: By

text: volume

text: dry

text: air

text: contains

text: nitrogen

text: oxygen

text: argon

text: carbon

text: dioxide

text: and

text: small

text: amounts

text: of

text: other

text: gases

text: Air

text: also

text: contains

text: variable

text: amount

text: of

text: water

text: vapor

text: on

text: average

text: around

text: at

text: sea

text: level

text: and

text: over

text: the

text: entire

text: atmosphere

text: Air

text: content

text: and

text: atmospheric

text: pressure

text: vary

text: at

text: different

text: layers

text: and

text: air

text: suitable

text: for

text: the

text: survival

text: of

text: terrestrial

text: plants

text: and

text: terrestrial

text: animals

text: is

text: found

text: only

text: in

text: Earth

text: 's

text: troposphere

text: and

text: artificial

text: atmospheres

text: The

text: atmosphere

text: has

text: mass

text: of

text: about

text: kg

text: three

text: quarters

text: of

text: which

text: is

text: within

text: about

text: km

text: mi

text: ft

text: of

text: the

text: surface

text: The

text: atmosphere

text: becomes

text: thinner

text: and

text: thinner

text: with

text: increasing

text: altitude

text: with

text: no

text: definite

text: boundary

text: between

text: the

text: atmosphere

text: and

text: outer

text: space

text: The

text: Kármán

text: line

text: at

text: km

text: mi

text: or

text: of

text: Earth

text: 's

text: radius

text: is

text: often

text: used

text: as

text: the

text: border

text: between

text: the

text: atmosphere

text: and

text: outer

text: space

text: Atmospheric

text: effects

text: become

text: noticeable

text: during

text: atmospheric

text: reentry

text: of

text: spacecraft

text: at

text: an

text: altitude

text: of

text: around

text: km

text: mi

text: Several

text: layers

text: can

text: be

text: distinguished

text: in

text: the

text: atmosphere

text: based

text: on

text: characteristics

text: such

text: as

text: temperature

text: and

text: composition

text: The

text: study

text: of

text: Earth

text: 's

text: atmosphere

text: and

text: its

text: processes

text: is

text: called

text: atmospheric

text: science

text: aerology

text: Early

text: pioneers

text: in

text: the

text: field

text: include

text: Léon

text: Teisserenc

text: de

text: Bort

text: and

text: Richard

text: Assmann

text: In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes:

text: In

text: physics

text: radiation

text: is

text: the

text: emission

text: or

text: transmission

text: of

text: energy

text: in

text: the

text: form

text: of

text: waves

text: or

text: particles

text: through

text: space

text: or

text: through

text: material

text: medium

text: This

text: includes

text: Measurement is the assignment of a number to a characteristic of an object or event, which can be compared with other objects or events. The scope and application of a measurement is dependent on the context and discipline. In the natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the "International vocabulary of metrology" published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioral sciences, measurements can have multiple levels, which would include nominal, ordinal, interval, and ratio scales.

text: Measurement

text: is

text: the

text: assignment

text: of

text: number

text: to

text: characteristic

text: of

text: an

text: object

text: or

text: event

text: which

text: can

text: be

text: compared

text: with

text: other

text: objects

text: or

text: events

text: The

text: scope

text: and

text: application

text: of

text: measurement

text: is

text: dependent

text: on

text: the

text: context

text: and

text: discipline

text: In

text: the

text: natural

text: sciences

text: and

text: engineering

text: measurements

text: do

text: not

text: apply

text: to

text: nominal

text: properties

text: of

text: objects

text: or

text: events

text: which

text: is

text: consistent

text: with

text: the

text: guidelines

text: of

text: the

text: International

text: vocabulary

text: of

text: metrology

text: published

text: by

text: the

text: International

text: Bureau

text: of

text: Weights

text: and

text: Measures

text: However

text: in

text: other

text: fields

text: such

text: as

text: statistics

text: as

text: well

text: as

text: the

text: social

text: and

text: behavioral

text: sciences

text: measurements

text: can

text: have

text: multiple

text: levels

text: which

text: would

text: include

text: nominal

text: ordinal

text: interval

text: and

text: ratio

text: scales

text: Physics (from , from "phúsis" "nature") is the natural science that involves the study of matter and its motion and behavior through space and time, along with related concepts such as energy and force. One of the most fundamental scientific disciplines, the main goal of physics is to understand how the universe behaves.

text: Physics

text: from

text: from

text: phúsis

text: nature

text: is

text: the

text: natural

text: science

text: that

text: involves

text: the

text: study

text: of

text: matter

text: and

text: its

text: motion

text: and

text: behavior

text: through

text: space

text: and

text: time

text: along

text: with

text: related

text: concepts

text: such

text: as

text: energy

text: and

text: force

text: One

text: of

text: the

text: most

text: fundamental

text: scientific

text: disciplines

text: the

text: main

text: goal

text: of

text: physics

text: is

text: to

text: understand

text: how

text: the

text: universe

text: behaves

text: A thermometer is a device that measures temperature or a temperature gradient. A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a mercury-in-glass thermometer) in which some physical change occurs with temperature, and (2) some means of converting this physical change into a numerical value (e.g. the visible scale that is marked on a mercury-in-glass thermometer). Thermometers are widely used in industry to control and regulate processes, in the study of weather, in medicine, and in scientific research.

text: thermometer

text: is

text: device

text: that

text: measures

text: temperature

text: or

text: temperature

text: gradient

text: thermometer

text: has

text: two

text: important

text: elements

text: temperature

text: sensor

text: e.g.

text: the

text: bulb

text: of

text: mercury

text: in

text: glass

text: thermometer

text: in

text: which

text: some

text: physical

text: change

text: occurs

text: with

text: temperature

text: and

text: some

text: means

text: of

text: converting

text: this

text: physical

text: change

text: into

text: numerical

text: value

text: e.g.

text: the

text: visible

text: scale

text: that

text: is

text: marked

text: on

text: mercury

text: in

text: glass

text: thermometer

text: Thermometers

text: are

text: widely

text: used

text: in

text: industry

text: to

text: control

text: and

text: regulate

text: processes

text: in

text: the

text: study

text: of

text: weather

text: in

text: medicine

text: and

text: in

text: scientific

text: research

text: Celsius, also known as centigrade, is a scale and unit of measurement for temperature. As an SI derived unit, it is used by most countries in the world. It is named after the Swedish astronomer Anders Celsius (17011744), who developed a similar temperature scale. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature interval, a difference between two temperatures or an uncertainty. Before being renamed to honour Anders Celsius in 1948, the unit was called "centigrade", from the Latin "centum", which means 100, and "gradus", which means steps.

text: Celsius

text: also

text: known

text: as

text: centigrade

text: is

text: scale

text: and

text: unit

text: of

text: measurement

text: for

text: temperature

text: As

text: an

text: SI

text: derived

text: unit

text: it

text: is

text: used

text: by

text: most

text: countries

text: in

text: the

text: world

text: It

text: is

text: named

text: after

text: the

text: Swedish

text: astronomer

text: Anders

text: Celsius

text: who

text: developed

text: similar

text: temperature

text: scale

text: The

text: degree

text: Celsius

text: can

text: refer

text: to

text: specific

text: temperature

text: on

text: the

text: Celsius

text: scale

text: as

text: well

text: as

text: unit

text: to

text: indicate

text: temperature

text: interval

text: difference

text: between

text: two

text: temperatures

text: or

text: an

text: uncertainty

text: Before

text: being

text: renamed

text: to

text: honour

text: Anders

text: Celsius

text: in

text: the

text: unit

text: was

text: called

text: centigrade

text: from

text: the

text: Latin

text: centum

text: which

text: means

text: and

text: gradus

text: which

text: means

text: steps

text: The kelvin is a unit of measure for temperature based upon an absolute scale. It is one of the seven base units in the International System of Units (SI) and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics. The kelvin is defined as the fraction of the thermodynamic temperature of the triple point of water (exactly 0.01 °C or 32.018 °F). In other words, it is defined such that the triple point of water is exactly 273.16 K.

text: The

text: kelvin

text: is

text: unit

text: of

text: measure

text: for

text: temperature

text: based

text: upon

text: an

text: absolute

text: scale

text: It

text: is

text: one

text: of

text: the

text: seven

text: base

text: units

text: in

text: the

text: International

text: System

text: of

text: Units

text: SI

text: and

text: is

text: assigned

text: the

text: unit

text: symbol

text: The

text: Kelvin

text: scale

text: is

text: an

text: absolute

text: thermodynamic

text: temperature

text: scale

text: using

text: as

text: its

text: point

text: absolute

text: zero

text: the

text: temperature

text: at

text: which

text: all

text: thermal

text: motion

text: ceases

text: in

text: the

text: classical

text: description

text: of

text: thermodynamics

text: The

text: kelvin

text: is

text: defined

text: as

text: the

text: fraction

text: of

text: the

text: thermodynamic

text: temperature

text: of

text: the

text: triple

text: point

text: of

text: water

text: exactly

text: or

text: In

text: other

text: words

text: it

text: is

text: defined

text: such

text: that

text: the

text: triple

text: point

text: of

text: water

text: is

text: exactly

text:
Sunset or sundown, is the daily disappearance of the Sun below the horizon as a result of Earth's rotation.
The Sun will set exactly due west at the equator on the the spring and fall equinoxes, each of which occurs only once a year.
The time of sunset is defined in astronomy as the moment when the trailing edge of the Sun's disk disappears below the horizon.
Near to the horizon, atmospheric refraction causes the ray path of light from the Sun to be distorted to such an extent that geometrically the Sun's disk is already about one diameter below the horizon when sunset is observed.

text: Sunset

text: or

text: sundown

text: is

text: the

text: daily

text: disappearance

text: of

text: the

text: Sun

text: below

text: the

text: horizon

text: as

text: result

text: of

text: Earth

text: 's

text: rotation

text: The

text: Sun

text: will

text: set

text: exactly

text: due

text: west

text: at

text: the

text: equator

text: on

text: the

text: the

text: spring

text: and

text: fall

text: equinoxes

text: each

text: of

text: which

text: occurs

text: only

text: once

text: year

text: The

text: time

text: of

text: sunset

text: is

text: defined

text: in

text: astronomy

text: as

text: the

text: moment

text: when

text: the

text: trailing

text: edge

text: of

text: the

text: Sun

text: 's

text: disk

text: disappears

text: below

text: the

text: horizon

text: Near

text: to

text: the

text: horizon

text: atmospheric

text: refraction

text: causes

text: the

text: ray

text: path

text: of

text: light

text: from

text: the

text: Sun

text: to

text: be

text: distorted

text: to

text: such

text: an

text: extent

text: that

text: geometrically

text: the

text: Sun

text: 's

text: disk

text: is

text: already

text: about

text: one

text: diameter

text: below

text: the

text: horizon

text: when

text: sunset

text: is

text: observed

question: field_of_work atmosphere of earth

answer: meteorology

text: meteorology

text: meteorology

text: meteorology

text: meteorology