All full time broadcast television stations in the United States are required to show at least three hours of children's educational programming per week. The shows must be specifically designed for education and receive an E/I rating. In most cases, these show on Saturday mornings when traditional viewership is low.
Cable television stations are exempt from this ruling. Because they do not broadcast over the public airwaves, they do not fall under the purview of the U.S. Federal Communications Commission. Many channels on cable television are especially dedicated to showing content aimed at children. Nickelodeon is one of the original cable channels that cater specifically to children. With its sister channel, Nick Jr., it airs content aimed at children from toddlers to pre-teens. The Disney Channel and Disney Jr. also seek to capture this demographic.
The Cartoon Network also shows children's shows but it shifts toward adult-themed entertainment after 7 p.m. PBS also shows television programming aimed at children. Its newly named children's group is called PBS Kids and features classic shows such as "Sesame Street," "The Electric Company," "Arthur" and "Sid the Science Kid." An aggregate channel, TWCK, or Time Warner Cable Kids, which was formed in 1993, is a free channel that caters to preschoolers and is available on most major cable networks.