Monthly Archives: August, 2010
How does a lie detector work?
A lie detector is a kind of machine that records changes in such things as a person’s breathing and heart and heartbeat while he is being questioned. Sometimes it is hard to know when a person tells a lie. But most people feel guilty when they lie. When a person lies, certain body reactions may …
Where is paper money made?
Paper money is printed by the Bureau of Engraving and Printing at Washington, D.C The Bureau of Engraving and Printing in Washington, D.C., is where the United States government prints paper money. Skilled engravers use sharp tools to cut the designs for bills into steel plates. Many engravers work on each plate. One works on …
Knowledge Power 