- Of, relating to, using, producing, or caused by heat.
- Intended or designed in such a way as to help retain body heat: thermal underwear.
A rising current of warm air.
thermally ther'mal·ly adv.
Dictionary:
ther·mal (thûr'məl) ![]() |
A rising current of warm air.
thermally ther'mal·ly adv.| Veterinary Dictionary: thermal |
Pertaining to heat.
| Word Tutor: thermal |
Do you wear thermal underwear on cold winter days?
| Wikipedia: Thermal |
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A thermal column (or thermal) is a column of rising air in the lower altitudes of the Earth's atmosphere. Thermals are created by the uneven heating of the Earth's surface from solar radiation, and an example of convection. The Sun warms the ground, which in turn warms the air directly above it.[1]
The warmer air expands, becoming less dense than the surrounding air mass. The mass of lighter air rises, and as it does, it cools due to its expansion at lower high-altitude pressures. It stops rising when it has cooled to the same temperature as the surrounding air. Associated with a thermal is a downward flow surrounding the thermal column. The downward moving exterior is caused by colder air being displaced at the top of the thermal.
The size and strength of thermals are influenced by the properties of the lower atmosphere (the troposphere). Generally, when the air is cold, bubbles of warm air are formed by the ground heating the air above it and can rise like a hot air balloon. The air is then said to be unstable. If there is a warm layer of air higher up, an inversion can prevent thermals from rising high and the air is said to be stable.
Thermals on the Sun typically form hexagonal prisms (Bénard cells).
Thermals are often indicated by the presence of visible cumulus clouds. When a steady wind is present thermals and their respective cumulus clouds can align in rows oriented with wind direction. Cumulus clouds formed by the rising air in a thermal as it cools and ascends, until the water vapor in the air begins to condense into visible droplets. The condensing water releases latent heat energy allowing the air to rise higher. Very unstable air can reach the level of free convection (LFC) and thus rise to great heights condensing large quantities of water and so forming showers or even thunderstorms.
Thermals are one of the many sources of lift used by soaring birds and gliders to soar.
A similar phenomenon can be seen in a lava lamp.
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
| Translations: Thermal |
Dansk (Danish)
adj. - varme-, termisk, varm
n. - termisk opvind, termik
idioms:
Nederlands (Dutch)
warmte-, warmwater-, thermisch, opstijgende warme luchtstroom
Français (French)
adj. - thermal, thermique
n. - ascendance thermique, courant ascendant
idioms:
Deutsch (German)
n. - Thermik, (aufwärts gerichtete Warmluftbewegung), kälteisolierende Kleidung
adj. - thermisch, Wärme-, heiß
idioms:
Ελληνική (Greek)
n. - ρεύμα θερμού αέρα
adj. - (φυσ.) θερμικός, θερμαντικός
idioms:
Italiano (Italian)
corrente ascendente, termale
Português (Portuguese)
n. - termal
adj. - térmico (m), calorífico (m)
Русский (Russian)
теплый, горячий, термальный, тепловой, теплотворный
Español (Spanish)
adj. - térmica, térmico, termal
n. - corriente térmica
idioms:
Svenska (Swedish)
n. - termisk uppvind
adj. - värme-, termisk-
中文(简体)(Chinese (Simplified))
热的, 烫的, 热量的, 上升温暖气流
idioms:
中文(繁體)(Chinese (Traditional))
adj. - 熱的, 燙的, 熱量的
n. - 上升溫暖氣流
idioms:
한국어 (Korean)
adj. - 열의, 보온성이 좋은, 정열적인
n. - 상승 온난 기류
日本語 (Japanese)
adj. - 熱の, 温泉の, 熱い
n. - サーマル
idioms:
العربيه (Arabic)
(الاسم) ألحار (صفه) حار, حراري
עברית (Hebrew)
adj. - של חום, חומני, תרמי
n. - זרם אוויר חם, ברבים: לבנים תחתונים מחממים
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| thermaburn | |
| DTA | |
| thermal resistance |
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![]() | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more | |
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