Thermal Convection and Viscosity … Page 1 of 11 Thermal Convection and Viscosity of a Fluid©

Objectives: Experiment with thermal convection. Illustrate how thermal energy (heat) can generate motion (flow) in a fluid. The thermal convection in this model is similar to the convection that is inferred for the Earth's mantle. Convection can produce horizontal flow that can cause (or is related to) plate motions. Investigate the viscosity of a fluid and illustrate that the Earth's mantle can be thought of as a solid for short duration processes (such as the propagation of seismic waves), and as a very viscous fluid for long duration processes (such as mantle convection and plate tectonic movements). Materials: 1 Glass bread loaf dish (1.5 liter; a 2 liter, 20x20 cm or 8x8 inch glass dish can be substituted if two Sterno cans or 3 small candles are used because of the extra width of the container) 2 Ceramic coffee cups 1 small can Sterno or 2 small candles vegetable oil (about 800-1000 ml) 10 ml ( ~ 2 teaspoons) thyme spoon matches metric ruler stopwatch funnel (to pour oil back into container) 3 pieces of thin (about 2mm, or 1/16 " thick) balsa wood, each 4x10 cm For viscosity experiment: Karo light corn syrup (about 60 ml) Cookie sheet Aluminum foi