Viscosity

Illustration of viscosity; the violet fluid at the bottom has a higher viscosity than the clear one above

Viscosity is a physical property of fluids. It shows resistance to flow.[1] In a simple example, water has a low viscosity, as it is "thin". Syrup and tar, on the other hand, have a high viscosity, as they are "thick". A way to test for viscosity is the speed at which the substance runs down a slope. Syrup would reach the bottom very slowly, whereas water would be a lot quicker.

There are two types of viscosity: dynamic viscosity, measured in pascal seconds, and kinematic viscosity, measured in metres per second squared.[2]

Viscosity is used as a way to predict when volcanoes erupt. When the lava comes out very thickly (viscous), there is more chance that it will erupt violently. This is because the lava has a hard time getting out and may burst out when it can. If the lava is thin (low viscosity), then it just flows out like water.[3]

The word viscous comes from the Latin viscum, meaning sticky.[4]

Other Languages
Afrikaans: Viskositeit
العربية: لزوجة
asturianu: Mafa
azərbaycanca: Özlülük
Bân-lâm-gú: Liâm-tō͘
беларуская: Вязкасць
български: Вискозитет
bosanski: Viskoznost
català: Viscositat
čeština: Viskozita
Cymraeg: Gludedd
dansk: Viskositet
Deutsch: Viskosität
eesti: Viskoossus
Ελληνικά: Ιξώδες
English: Viscosity
español: Viscosidad
Esperanto: Viskozeco
euskara: Biskositate
فارسی: گران‌روی
français: Viscosité
Gaeilge: Slaodacht
한국어: 점성
हिन्दी: श्यानता
hrvatski: Viskoznost
Bahasa Indonesia: Viskositas
íslenska: Seigja
italiano: Viscosità
עברית: צמיגות
Basa Jawa: Viskositas
қазақша: Тұтқырлық
Kreyòl ayisyen: Viskozite
latviešu: Viskozitāte
Lëtzebuergesch: Viskositéit
lietuvių: Klampumas
magyar: Viszkozitás
македонски: Вискозност
മലയാളം: ശ്യാനത
Bahasa Melayu: Kelikatan
монгол: Зунгааралт
Nederlands: Viscositeit
नेपाली: भिस्कोसीटि
日本語: 粘度
norsk: Viskositet
norsk nynorsk: Viskositet
ਪੰਜਾਬੀ: ਲੇਸ
پښتو: خټنه
polski: Lepkość
português: Viscosidade
română: Viscozitate
русский: Вязкость
Scots: Viscosity
slovenčina: Viskozita
slovenščina: Viskoznost
српски / srpski: Вискозност флуида
srpskohrvatski / српскохрватски: Viskoznost fluida
svenska: Viskositet
Türkçe: Akmazlık
українська: В'язкість
اردو: لزوجت
Tiếng Việt: Độ nhớt
粵語: 黏度
中文: 黏度