In this episode on heat, the Project X team looks at how we stave off dehydration in the scalding, suffocating heat of an unrelenting sun? Dr. Alters looks at how plants and animals manage to thrive in a place where it's forty degrees in the shade. Then Dr. Fleck and grad student Marc Huot find that, centuries ago, the Sinagua people knew alot about thermodynamics. And engineers today are using those same ideas to build cooler houses. Dr. Gardy gets all sweaty to find out how our body deals with extreme heat.