How does the temperature of engin oil change the viscosity of it?

im doing a physics project for a2 and its based on going on on trip from differnt temperatures and how this will effect my engine oil im pretty stuck about which oils to use and stuff like that and any help would be much appriciated How does the temperature of engin oil change the viscosity of it?It acts a lot like molasses. The colder it is the more viscose the oil will be, and the warmer it is the thinner it will be. With a multi-weight the oil will not thin out as much as the temperature rises because it has Special polymers in it that unwind as the temperature increases. A multi-weight is used so that the oil will flow when the engine is cold, but when the car warms up, it will not lose the protection the way a lighter oil would.

If you put a drop of oil on a piece of steel, then drop a hammer on it, the do the same with hot oil you will see a big difference in the viscosity. How does the temperature of engin oil change the viscosity of it?because the heat activates the particles that the oil consists of,, this then makes the oil more viscous and in effect thinner so it will circulate the engine more effectively.How does the temperature of engin oil change the viscosity of it?also, when you buy oil there is a viscosity reading on the lable, eg 10w - 40w, 40w is the thickness and room temp and 10w is the car running temp 0w -15w is for new car and 25w - 50w for older worn cars