do high viscosity liquids take longer to heat

The ratio of these two quantities is the viscosity hence η = σ/ The shear rate (sometimes called the strain rate or velocity gradient), which is the proper measure of the rate of deformation in the fluid undergoing shear flow. In shear flow-where we imagine the flow as hypothetical layers of fluid flowing over each other-we define the relevant parameters as (see Figure 1) σ the shear stress (force per unit area) at the boundary of the fluid to produce the flow, and Quantitatively, viscosity is defined as the stress in a particular ideal flow-field divided by the rate of deformation of the flow. Viscosity can depend on the type of flow (shear and/or extensional), its duration and rate, as well as the prevailing temperature and pressure. (Sugar, salt, etc.) There are mathematical equations we can use to calculate how MUCH these things affect the heat capacity, but I won't go into them.Viscosity is that property of a fluid which is the measure of its resistance to flow (i.e.

Furthermore dissolving THINGS inside of the water can also increase (or decrease) this amount of energy. Water takes more energy (more time in the microwave) to heat up by 10 degrees than ethanol would to heat up the same 10 degrees. The microwave outputs a specific amount of heat per second, therefore things that require more heat need to be in the microwave longer.ĮLI'mOlder: Everything has a property called 'specific heat' or 'heat capacity' (different names, same concept.) For example, water takes 4.184 Joules (a measure of energy) to heat up 1 gram by 1 degree Celsius.Įthanol (drinking alcohol) takes 2.18 Joules to heat up 1 gram by 1 degree Celsius.ĭifferent things take different amounts of energy to heat up by the same amount of temperature. The pear takes less total energy to heat up, but the formula gets an extra kick from the microwave specifically.ĮLI5: Some things take more energy to heat up than other things. However if you were to heat them up in an oven for example, the pear has a much better chance of heating up quicker, as now the sensitivity to microwaves is no longer a limiting factor. Microwaves are explicitly designed to cause high energy vibrations in water, and lesser energy vibrations to anything that is not water.Īs formula will contain more water content than a pear for equal mass, it should take longer for the pear to heat up, because the pear has many components that are not sensitive to microwaves. The second thing to keep in mind is how a microwave works. This is known as the specific heat and is a quantitative measure of the relationship between energy and temperature. Because each mode of vibration requires its own unit of energy, then the more modes of vibration available, the more energy will be required to increase the temperature. Water is unique in that it has a very high number of modes of vibration compared to many other substances. If one unit of energy causes one of those modes of vibrations, then it requires one unit of energy for each type of vibration for a one unit increase in the temperature. If you look at This Gif you can see how a single molecule of water can distribute extra kinetic energy through different modes of vibration.

Do high viscosity liquids take longer to heat