Move the straw over to the relief map. Take your thumb off the top of the straw so the molasses pours out. This simple model can demonstrate the factors that influence where lava will flow. For example, start your eruptions at the summit or high or low on a rift zone. The U.S. Geological Survey's Cascade Volcano Observatory provides detailed histories on each Cascade volcano.
Some volcanoes produce fluid mudflows that do travel far down the volcano.
This demonstration could be easily modified to show areas that are susceptible to mudflows on a volcano.