Why does the viscosity of air increase with temperature?
In other words, increasing gas temperature causes the gas molecules to collide more often. This increases the gas viscosity because the transfer of momentum between stationary and moving molecules is what causes gas viscosity. As a liquid is heated, the viscosity decreases just the opposite effect as in gases.
The former effect causes a decrease in the shear stress while the latter causes it to increase. The result is that liquids show a reduction in viscosity with increasing temperature. With high temperatures, viscosity increases in gases and decreases in liquids, the drag force will do the same.
- Heating a substance causes molecules to speed up and spread slightly further apart, occupying a larger volume that results in a decrease in density. Hot water is less dense and will float on room-temperature water. Cold water is more dense and will sink in room-temperature water.
- Fluid viscosity changes with temperature. Pressure has a small impact on gas viscosity and the pressure impact on the viscosity of a liquid is very small. When studying multiphase liquids (a mixture of gas, liquid and solids) there are other factors that come into play.
- Therefore, increasing temperature decreases viscosity. In general, the liquids tend to expand when their temperature increases. For example, the same mass of boiling water occupies more volume at 100 degrees Celsius than at 20 degrees Celsius. Therefore, increasing temperature decreases density.
Temperature and Pressure Effects. The effect of temperature and pressure on a liquid can be described in terms of kinetic-molecular theory. Note how temperature effects the motion of the atoms or molecules in a liquid. As the temperature of a solid, liquid or gas increases, the particles move more rapidly.
- Temperature impacts both the chemical and biological characteristics of surface water. It affects the dissolved oxygen level in the water, photosynthesis of aquatic plants, metabolic rates of aquatic organisms, and the sensitivity of these organisms to pollution, parasites and disease.
- This happens when the temperature of air is increased. Warm air molecules have more energy, so they move faster and create more pressure. Likewise, cold air has less energy and therefore exerts less pressure on its surroundings. The denser the air is, the more molecules there are in that given space.
- 1) If the volume of a container is increased, the temperature increases. 2) If the volume of a container is decreased, the temperature decreases. 1) Suppose the temperature is increased. This means gas molecules will move faster and they will impact the container walls more often.
Updated: 27th September 2018