A very thin and fluid magma erupts more easily and forms gentle mountain slopes, while a very thick magma erupts explosively and forms a fat lava flow and steep mountain slopes. The viscosity of molten rock or magma determines how easily a volcano will erupt, and what shape the lava flows and resulting mountains will take on. Volcanologists (people who study volcanoes) have a big interest in viscosity, too. Blood viscosity, like most things in medicine, has a happy medium. If blood is 'too thin,' or lacks viscosity, however, then the patient is at risk for bruising or bleeding events. If blood is 'too thick,' or viscous, a patient can develop blood clots. Likewise, in medicine, doctors try to keep blood viscosity in the correct range. It is difficult, for example, to transport highly viscous crude oil through offshore pipelines, so scientists and engineers use a variety of methods to try and lower the oil's resistance to flow through the pipelines. Viscosity is a very important quality of liquids that scientists, engineers, and even doctors are frequently trying to measure and change. Likewise, in highly viscous liquids (those with high internal friction), the resistance to flow is high. If, for example, you try to ride your bike with the hand brakes on (a form of friction), it is difficult to roll the bike forward. The viscosity, or resistance to flow, goes way down as the temperature goes up.Īs a measure of a liquid's resistance to flow, viscosity can be thought of as friction inside the liquid.

If you set the honey bear in a pan of warm water for a few minutes and try again, what happens? One little squeeze and honey comes gushing out all over your toast. As the temperature goes down, the viscosity, or resistance to flow, goes way up and you can squeeze and squeeze all you want, but very little honey comes out. On a cold winter morning, have you ever tried to squeeze some honey out of the honey bear onto your toast? It is pretty tough, huh? Honey is one of those liquids that is very sensitive to temperature.

The line test for viscosity