Does temperature affect the viscosity of motor oil, olive oil, and salt water?
Yes, temperature affects the viscosity of these liquids, but changes in the viscosity of salt water are quite small and would be difficult to observe. In general, as the temperature of a liquid increases, the viscosity decreases and the liquid becomes more easy to pour. This is true of most liquids. However, some kinds of motor oil do not act that way. Ideally one would want the viscosity of the oil to remain the same when the engine is hot as when it is cold. So, motor oil usually includes additives that are designed to lessen changes in viscosity due to temperature. Some motor oils are especially designed to be less viscous (thinner) when cold and more viscous (thicker) when hot. For example, multi-viscosity or multi-grade motor oils exhibit a low viscosity at low temperatures and a higher viscosity at high temperatures. The idea behind this is to provide a thin oil when the motor is started (usually at a cooler temperature) and to provide an oil of the proper thickness at the operat
