A focused look at urbanization in first and third world societies . Interesting charts compare urbanization trends in more vs. less developed regions of world.

Quiz where the player calculates the answers for two multiplication questions involving one- and two-digit numbers, with no regrouping, and then chooses the correct symbol for comparing the products (i.e., >, <, or =).

Quiz where the player compares two numbers between one and ten, which are represented by numerals and dots.

Quiz where the player compares two numbers between one and thirty, and states whether the first number is less than, equal to, or greater than the second number.

Quiz where the player calculates the answers for two multiplication questions involving one- and two-digit numbers, with regrouping, and then chooses the correct symbol for comparing the products (i.e., >, <, or =).

You've probably heard that compact fluorescent light bulbs are more efficient than incandescent bulbs. More of the electricity they use goes into producing light, and less into producing heat than with incandescent bulbs. How much more...

Why do teenagers seem so much more impulsive, so much less self-aware than grown-ups? Cognitive neuroscientist Sarah-Jayne Blakemore compares the prefrontal cortex in adolescents to that of adults, to show us how typically "teenage"...

A map from 1906 of the Greater Antilles and Bahama Island group of the West Indies. The map shows capitals, major cities, and ports, terrain and coastal features, submerged banks or reefs, and smaller islands. The water depths are...