Replicates the experiments J.J. Thomson conducted to develop his model of an atom. Light is produced when an electric current is passed through a tube. When a magnetic charge is introduced, the rays are deflected.

The mass number of an atom is the sum of its protons and neutrons. The mass number of sulfur is 32.

The mass number of an atom is the sum of its protons and neutrons.

The nucleus is the dense core of an atom. It contains over 99 percent of the mass of an atom, but occupies a miniscule amount of the space.

In Rutherford's model of an atom, positively charged particles are concentrated in a small, dense center of an atom called the nucleus. Negatively charged electrons are scattered around the nucleus.

Electrons are precisely one two-thousandth of the mass of a proton or neutron.

The nucleus of an atom contains positively charged protons and neutrally charged neutrons. Negatively charged electrons orbit the nucleus.

In our new episode of Homeroom we are joined by, Kerri Hopkins and Anne Dibble from the Beverly Taylor Sorenson Arts Learning Program to discuss how all teachers can bring more art into their classrooms. We learn how arts can improve academic performance across all subjects, the need to overcome our fears when expanding into the arts, and the different programs available to Utah schools through BTSALP.

The food pyramid depicts the five major food groups: grains, fruit, vegetables, milk, meat and beans.

Scientists unravel the mysteries and misconceptions surrounding precious gemstones. Learn about the chemistry, physics, and geology of gems and crystals. Recorded in the Hall of Geology, Gems, and Minerals at the Smithsonian National Museum of Natural History.

Africa's dynamic culture has always been fueled by the movement of people, things, and ideas. Africans use cultural traditions as a starting point for new innovations. In friendship, conversation, daily life, and university classrooms, African artists learn traditional techniques and develop the latest ideas.

From the Field Museum in Chicago, IL, this electronic field trip takes you through five million years of human evolution so you can picture our beginnings and imagine our future. During the program you will experience seven fossil stations that highlight a different human ancestor at a particular moment in time.

Every day, thousands of cargo ships around the world are busy loading and unloading their cargo. In addition to their intended cargo, however, these enormous vessels also ship other, unintended cargo. Hidden in the ships' ballast water - water used to stabilize the ships when not carrying a load - and stuck to the ships' hulls, millions of tiny plants and animals are also making their way around the world. These non-native organisms are released with ballast water into a new port during loading and unloading of cargo or are scraped off the hull. Though not all survive the big trip, some do, and even adapt well to the environment. Some do so well that they out-compete local species, and others introduce diseases that quickly spread through the ecosystem.

For two days, the Nation's Capitol will be turned into one of the largest classrooms in the country. Join Members of Congress, lobbyists, government officials, and your fellow students as we explore a national issue, discover the legislative process, and maneuver the forces that shape national policy.

For two days, the Nation's Capitol will be turned into one of the largest classrooms in the country. Join Members of Congress, lobbyists, government officials, and your fellow students as we explore a national issue, discover the legislative process, and maneuver the forces that shape national policy.

This electronic field trip will convene in February 2004 at the grassroots level. Students in classrooms across the country will research the issue, solicit feedback from constituents, and define their position.

Join the Smithsonian's National Air and Space Museum for an anniversary like no other. Celebrate the occasion by visiting the Museum's new exhibition: The Wright Brothers & The Invention of the Aerial Age.

Join the Smithsonian's National Air and Space Museum for an anniversary like no other. Celebrate the occasion by visiting the Museum's new exhibition: The Wright Brothers & The Invention of the Aerial Age.

Many Americans are surprised to learn that women once played professional baseball in the All-American Girls Professional Baseball League (AAGPBL) from 1943-1954. Founded by Chicago Cubs owner Phil Wrigley in order to entertain Americans - and keep ballparks full - during World War II, the league provided unprecedented opportunity for young women to play professional baseball, see the country, and aspire to careers beyond the traditional roles of teacher, secretary, nurse, librarian, or housewife.