Racing Marbles to Measure Viscosity
Have you ever noticed that some liquids are more difficult than others to squeeze from a container? Honey is a great example. Depending on its temperature, it may be especially slow to flow from the bottle. (If you warm it up, it may flow more quickly!) While it may seem like the quality of the honey you are noticing is its "thickness" or "thinness," another way to talk about what you are seeing is to talk about its viscosity.
In this week's chemistry-themed family science activity, families explore viscosity, a property of liquids that is a measure of the friction inside the liquid. When honey is cold, it may be very slow to flow because its viscosity is high—there is more friction within the liquid that is slowing it down. Viscosity is a property that can be changed, however. What happens when you warm up honey? With this science activity, families measure and compare the viscosity of different household liquids by doing a simple drop test and measuring how long it takes a marble to pass through each liquid. How do you think different liquids in your kitchen will compare in terms of viscosity? What other properties of a liquid are related to the viscosity? Race some marbles to find out!
- Race Your Marbles to Discover a Liquid's Viscosity (Science Buddies project idea)
- Marble Race—in Liquid! (science activity at Scientific American)