This episode explores the wave theory of light as studied by mankind, noting that light has played an important role in scientific progress, with such early experiments from over 2000 years ago involving the camera obscura by the Chinese philosopher Mozi. Tyson describes the work of the 11th century Arabic scientist Ibn al-Haytham, considered to be one of the first to postulate on the nature of light and optics leading to the concept of the telescope, as well as one of the first researchers to use the scientific method. Tyson proceeds to discuss the nature of light as discovered by mankind. Work by Isaac Newton using diffraction through prisms demonstrated that light was composed of the visible spectrum, while findings of William Herschel in the 19th century showed that light also consisted of infrared rays. Joseph von Fraunhofer would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These Fraunhofer lines would later be determined to be caused by the absorption of light by electrons in moving between atomic orbitals when it passed through atoms, with each atom having a characteristic signature due to the quantum nature of these orbitals. This since has led to the core of astronomical spectroscopy, allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of dark matter.

A documentary about the highs and lows of children in show business, featuring interviews and examinations of the lives and careers of the most famous former child actors in the world. The film opens with a montage spotlighting most of those people, along with others who had better luck (like Ron Howard, Jodie Foster, and Daniel Radcliffe), finally landing on a photograph of the documentary’s director, Alex Winter, who was a child actor on and off Broadway.
The reality of child stardom is that an essential unreality is baked into it. That‘s why it’s so often about the wheels coming off at high speeds. Child stardom now feels like one of the last aspirations of a decadent, no-future America. And 'Showbiz Kids' is an invaluable primer of its risks and rewards.

It all begins as a study on the psychology of prison life led by Stanford psychology professor Dr. Philip Zimbardo. 24 volunteers - 12 guards and 12 prisoners - have agreed to spend the next two weeks recreating life in a correctional facility. Normal people can become monsters, given the right situation, that's the standard narrative of the Stanford Prison Experiment, one of the most famous psychological experiments of all time.
But what if the cause of its participants' cruel behavior wasn't what we've always been told?

Julien Temple's epic time-travelling voyage to the heart of his hometown. From musicians, writers and artists to dangerous thinkers, political radicals and above all ordinary people, this is the story of London's immigrants, its bohemians and how together they changed the city forever. Reaching back to the dawn of film in London at the start of the 20th century, the story unfolds through film archive, voices of Londoners past and present and the flow of popular music across the century; a stream of urban consciousness, like the river which flows through its heart. It ends now, as London prepares to welcome the world to the 2012 Olympics.

Austrian director Michael Glawogger travels to five countries to focus on some of the worst jobs imaginable: Ukrainian miners crawl into tiny cracks in old coal pits to scratch out a few bags of winter fuel; Indonesian workers trudge long distances carrying baskets with hundreds of pounds of sulfur chunks extracted from a steaming mountain; Pakistanis risk explosions and burial under tons of scrap iron as they dismantle huge carrier ships. The visuals are everything here. Despite the hardships depicted, many sequences have a dreamlike beauty. In addition, the director has a bone-dry sense of irony; during the Ukraine scenes, he frequently cuts away to a statue of Stakhanov, the "hero" lauded by the Soviets for his superhuman work habits. He also shows us an old German smelting works that's been converted into a theme park.

A guide to plants that thrive in human-dominated environments, including trees that grow across canyons in India, which have developed into living bridges. The programme examines the origins of growing crops and the ongoing influence on the world of wild plants, as well as efforts to preserve species, from snipers firing pesticide bullets from helicopters to fend off invasive plants to plants being painstakingly pollinated using a paintbrush.