What is the Viscosity of Water?
The viscosity of water at a temperature of 20 degrees Celsius is approximately 0.01 poise or 10-3 Pa.s (Pascal seconds). Viscosity is a measure of the resistance of a fluid to deformation at a given rate. For liquids such as water, viscosity can be perceived as a measure of the liquid’s resistance to flow. Therefore, it can be understood that the viscosity of syrups and honey will be higher than the viscosity of water.
The SI unit for dynamic viscosity is pascal-second (Pa.s) or newton-second per metre squared (N.s/m2). It can be noted that the viscosity of water increases as the temperature is decreased. The converse is also true, i.e. the viscosity of water decreases as the temperature is increased. The values of the dynamic viscosity of water at certain temperature ranges have been tabulated below.
| Temperature (in degrees Celsius) | Dynamic viscosity of water (in mPa.s) |
| 5 | 1.5182 |
| 10 | 1.3059 |
| 15 | 1.1375 |
| 20 | 1.0016 |
| 25 | 0.89 |
| 30 | 0.7972 |
| 35 | 0.7191 |
| 40 | 0.6527 |
| 45 | 0.5958 |
| 50 | 0.5465 |
Other Notable Properties of Water
- For most purposes, liquid water may be considered to be incompressible. Under ordinary conditions, the compressibility of liquid water varies from 4.4*10-10 Pa-1 to 5.1*10-10 Pa-1.
- The electrical conductivity of pure water is low and it is known to increase with the dissolution of a small amount of ionic content, such as sodium chloride.
- By running an electric current through it, liquid water can be divided into the elements hydrogen and oxygen. This process is generally referred to as electrolysis.
- Hydrogen is displaced from water by metallic elements that are more electropositive than hydrogen, particularly alkali metals and alkaline earth metals such as sodium, lithium, potassium, cesium, and calcium. These elements are known to form hydroxides upon reacting with water, releasing hydrogen in the process.
- The hydrogen atoms in a water molecule form a 104.5 ° angle with the oxygen atom. The atoms of hydrogen are similar to the two corners of the oxygen-centered tetrahedron. Lone pairs of valence electrons are at the other two corners, which do not engage in the bonding.
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Frequently Asked Questions on Viscosity of Water
What is the viscosity of water at a temperature of 20 degrees Celsius?
The viscosity of water at a temperature of 20 degrees Celsius is roughly equal to 0.01 poise or 10-3 Pa.s (Pascal seconds). Alternately, this value can be represented as 1.0016 mPa.s.
What are the 3 states of water?
The solid state of water is called ice. Water freezes at a temperature of 0 degrees Celsius to assume this state.
The liquid state of water makes up the majority of the planet’s surface. This state of water finds applications in many areas including industry.
The gaseous state of water is called water vapour. At a temperature of 100 degrees Celsius (at standard pressure) water reaches its boiling point and is converted into water vapour.
What is the appearance of water at STP?
At STP, water exists as a colourless and a tasteless liquid.
Why is water called a universal solvent?
Water is referred to as a universal solvent since it has the ability to dissolve most substances, including salts, sugar, acids, bases, and gases.
Is water acidic or basic?
Water is neither acidic nor basic in nature. It has a pH of 7, making it a neutral substance.
To learn more about the viscosity of water along with other important concepts related to water, such as the water cycle, register with BYJU’S and download our app.
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