(Encyclopedia) proton, elementary particle having a single positive electrical charge and constituting the nucleus of the ordinary hydrogen atom. The positive charge of the nucleus of any atom is due…
(Encyclopedia) radonradonrāˈdŏn [key], gaseous radioactive chemical element; symbol Rn; at. no. 86; mass no. of most stable isotope 222; m.p. about −71℃; b.p. −61.8℃; density 9.73 grams per liter at…
Dinosaurs lived throughout the Mesozoic Era, which began 245 million years ago and lasted for 180 million years. It is sometimes called the Age of the Reptiles. The era is divided into three…
Source: National Institute of Standards and Technology Physics Laboratory In Europe during most of the Middle Ages (roughly 500 to 1500 A.D.), technological advancement was at a virtual standstill…
Leonardo Da Vinci (1452–1519) Italian Renaissance artist who was most famous as a painter but also excelled at drawing (particularly the human anatomy),…
(Encyclopedia) physical fitness, combined good health and physical development. The object of any program of physical fitness is to maximize an individual's health, strength, endurance, and skill…
Check out these B&Bs in Maine, Massachusetts, and Vermont New England has something for every time of year. In autumn, there is no better place to go leaf peeping…
