The sighting of a new moon determines the beginning of the Islamic holy month of Ramadan. In this video from Religion & Ethics Newsweekly, follow the process of sighting a new moon for American Muslims.

In this video segment from Religion & Ethics Newsweekly, an American Muslim family observes Ramadan, the month in which Muslims fast daily from sunrise to sunset in order to demonstrate piety and develop self-restraint.

This video segment from Nature features ravens, the most intelligent birds in the crow family.

In this video segment from Cyberchase, the CyberSquad learns how to read a thermometer as they try to keep their chocolate sculpture from melting.

In this video segment from Cyberchase, Jackie and Inez figure out how to break an Electro-Root into 2/5, one of the ingredients for the antidote to MotherboardŒë_í_Œ_ virus.

In this video segment from Cyberchase, Matt and Digit divide up the healing stone and discover equivalent fractions.

Learn how ravens benefit from sharing information and working together in this video segment from Nature.

Learn about rotational forces by watching astronaut Jeffrey Williams spin objects onboard the International Space Station in this interactive activity adapted from NASA.

This video segment from Nature takes viewers to a road race in Death Valley.

In this lesson, based on the documentary Through My Eyes: The Charlie Kelman Story, students learn about the history and state-of-the-art of one of the world's most commonly performed surgical procedures--eye cataract removal and replacement.

The CyberSquad must divide 35 candies evenly among seven gargoyles in this video segment from Cyberchase.

In this video segment from Cyberchase, Jackie shows Buzz, Delete and Harold how to deal out rounds (or sets) of objects to solve a problem.

In this Nature video, watch a battle between a loggerhead turtle and a shark.

In this video segment from Nature, see the value that sharks can have on the tourism industry in an area.

In this Cyberchase video segment, the CyberSquad learns what happens to the area of a rectangle when the shape enclosed by the perimeter changes.

In this video segment from Religion & Ethics Newsweekly, view the reactions of citizens from Lewiston, Maine as Somali immigrants settle in their community.

In this video segment from Cyberchase, Hacker and the CyberSquad race to reach the Good Vibration on staircases that grow at different rates and have steps of varying sizes.

In this video segment from Cyberchase, the CyberSquad determines the fairness of a game in which there are three shapes distributed equally on nine squares.

In this video segment from Cyberchase, learn about the importance of creating a model as the CyberSquad designs a giant Trojan Ducky that will help them enter a fort without being noticed.