Really?

Clara giggled. "This is why I told you to seriously study science, Ri. If you had, you would have had this breakthrough a long time ago." 

Ri blinked, feeling slightly aggrieved. She didn't want to touch that science stuff with a ten foot pole. 

"Really?" She said doubtfully. 

"Really." Clara nodded, trying to convince her. "In terms of materials, water is among the best in terms of specific heat. Well… 'best' is subjective, but the short of it is that compared to other materials, water has a very high threshold for both accepting and retaining heat. 

"In terms of the scientific theory, for every joule of energy you spend, water will, on average, raise less in temperature than another material. At the same time, more energy has to be extracted from water, on average, for it to drop in temperature." 

Ri's eyes glowed. Though she hated science, she was still intelligent. This explanation alone was enough for her to understand.