Imagine you were walking barefoot near a hot spring, and the ground felt warm to your feet. Touching the water, it was hot! The heat is coming from deep underground, but how did it get there? What might be causing it? 

Imagine you were building a home to stay warm during the winter without using a furnace, in an area with geothermal activity. How might you do that? 

In some places, people use heat from the Earth to produce electricity. What kinds of conditions or locations do you think are best for this type of energy and why?