The Physics of Cooling Lava

The following calculations show how much molten lava would be cooled and solidified by 100 kg of water. The lava is assumed to be at 1000 degrees C and the water is assumed to be at 10 degrees C. The final temperature for the lava and the water is assumed to be 100 degrees C. These numbers are only approximate. The actual specific heat and latent heat of fusion for lava varies depending on the mineral composition. In his piece “Cooling the Lava”, John Mcphee gives a figure of 1.7 kg of lava cooled per 1 kg of water. My calculations show 2.7 kg of lava cooled per 1 kg of water. The range of values I found for specific and latent heats of magma would explain this difference. Also the crystallization process for lava in more complicated than this model shows.