By Michaeleen Doucleff, Source: NPR

Piscine Molitor “Pi” Patel did it to survive on the Pacific Ocean. Robert Redford used the trick in All Is Lost.

When you’re trapped on a boat, you can easily make fresh water, right? Simply let the sun heat up and evaporate salt water. Then trap the steam, condense it on a plastic surface and collect the fresh water. The liquid even gets sterilized in the process.

So why can’t people around the world who lack clean drinking water do something similar?

Turns out, desalinating or sterilizing water with solar energy is way harder than Hollywood makes it look. The process is super inefficient and way too slow to be practical.

Read more at: NPR