【Watch Sex (1994) Part 1】

The Watch Sex (1994) Part 1same process that turns the ocean blue also helps humpback whales find the coziest spot for raising their precious 1-ton calves.

Water molecules absorb all the colored photons of light (red, orange, yellow, blue) and the photons' energy. Water then turns that color energy into heat -- precisely what the blubber-less calves need to grow strong.

PBS explores this interplay between color and energy in its new series Forces of Nature,which premieres Sept. 14 at 8 p.m. ET.

In an exclusive clip shared with Mashable, scientists explain why the Dominican Republic is one of the few breeding and calving zones of the North Atlantic humpback whale.

The Silver Bank Marine Reserve, about 56 miles off the island, is exposed to the full power of the tropical sun. The sun's photons heat the brilliant blue seas to around 80 degrees Fahrenheit, or 26.6 degrees Celsius.

"It's a warm, safe place to give birth, and the reason that's the case has to do with the color of the ocean and the wavelengths that have been absorbed," Bill Gardner, vice president of programming for PBS, told Mashable.

As if baby whales weren't enough to tug at your heart strings, the United States announced last week that most populations of humpback whales are no longer on the U.S. endangered species list.

The National Oceanic and Atmospheric Administration (NOAA) said global conservation efforts over the past four decades have helped nine of 14 humpback population segments rebound from historically low levels.

Forces of Nature, a BBC co-production, will explore Earth's mysterious and intricate forces in four episodes: "Shape," "Color," "Motion," and "Natural Elements."

The series aims to "illustrate that the Earth is a system; everything is interdependent," Gardner said by phone. "It goes down to the molecular level."

The "Color" episode, which airs Sept. 28, will also feature birds of paradise in Papua New Guinea, whose plumage helps them blend into the rainforest or attract mates. A segment on the Serengeti in east-central Africa will explain why the ecosystem's forests, swamps and grasslands are lush and green.

"Color is a tangible, active thing that carries the energy of the sun," Gardner said.

The exclusive preview shows that while humpback whale calves thrive in the Silver Bank reserve's warm waters, for adults the area is essentially an underwater food desert. Mothers have little to feed on and instead live off a snack pack of blubber.

Once calves grow their own thin layer of fat, the whales will head thousands of miles to the north to the Gulf of Maine and other feeding grounds.

In the North Atlantic, the light of the sun is much weaker and waters are frigid. But the ocean is stocked with the tiny crustaceans, plankton and small fish that humpbacks prefer to gobble.

"Color is something that we all take for granted, and what we wanted to help demonstrate is that there's more to it than we initially think," Gardner said.