What does the ancient earthquake detector do? it help tell the direction of where it came from and the slightest movement will make the ball fall if you are referring to the ancient china one Edit
Depending on the type of lava flow, the resulting rocks look very different. This was a pahoehoe flow. A lava flow is caused by a volcanic eruption. The lava can flow down the volcano at speeds ranging from 1/24 to 50 meters an hour. They can be 1,300 degrees fahrenheit or more. They are very destructive.
  Viscous lava is very sticky and thick and is more felsic (ie it contains more silica) than non-viscous lava. This type of lava makes for a very explosive volcano, becau â¦ se it's so sticky that it sticks to itself and can't exit the volcano until it explodes violently.   Non-viscous lava is more runny and is more mafic (has more iron, less silica). Volcanoes with non-viscous lava are less explosive because the lava just runs out slowly and no pressure builds.