# Homework Help: Heat transfer from cooling lava

1. Dec 4, 2013

### suchjoe

1. The problem statement, all variables and given/known data
The world's most active volcanos, such as the Kilauea volcano in Hawaii, can disgorge about 5 ✕ 105 m3 of 1000°C lava per day. What is the rate of heat transfer out of the earth by convection if this lava has a density of 2800 kg/m3 and eventually cools to 32°C? Assume that the specific heat of lava is the same as that of granite. Answer in MW.

2. Relevant equations
D=m/v
Q=mc(tf-ti)
P = Q/t

3. The attempt at a solution

Solved the density equation for mass (m=1.4*10E9kg)
Solved for Q (Q=1.07*10E15J)
Solved for P (P=1.24*10E10W or 12400MW)

Followed an example from book, what am I missing

2. Dec 5, 2013

### haruspex

I take it your answer has been marked wrong. I get 12390MW, so I would probably have been marked wrong too.

3. Dec 5, 2013

### suchjoe

Thanks for trying

4. Dec 5, 2013

### Staff: Mentor

What about the heat of solidification?

5. Dec 5, 2013

### suchjoe

Thanks chestermiller been searching for fusion number for granite found 100cal/gm can anyone verify