Electromagnetism (Encyclopedia of Science)
Electromagnetism is the force involving the interaction of electricity and magnetism. It is the science of electrical charge, and its rules govern the way charged particles of atoms interact. Electromagnetism is one of the four fundamental forces of the universe (gravity and the "strong" and "weak" forces that hold an atomic nucleus together are the other three). Because its effects can be observed so easily, electromagnetism is the best understood of these four forces.
Some of the rules of electrostatics, or the study of electric charges at rest, were first noted by the ancient Romans, who observed the way a brushed comb would attract particles. Until the nineteenth century, however, electricity and magnetism were thought to be totally different and separate forces. In 1820, a direct connection between the two forces was confirmed for the first time when Danish physicist Hans Christian Oersted (1777851) announced his discovery that an electric current, if passed through a wire placed near a compass needle, would make the needle move. This suggested that electricity somehow creates a magnetic force or field, since a compass needle moves by magnetism.
Shortly afterward, French physicist André Marie Ampère (1775836) conducted experiments in which he discovered that two parallel
(The entire section is 879 words.)
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Electromagnetism (Science Experiments)
How can electricity create a magnet?
Magnetism: How can a magnetic field be created and detected?
Design Your Own Experiment
is the energy produced by an electric current moving through a metal core. To understand electromagnetism, you need to understand the basics of electricity.
Electricity is produced by the movement of AtomsThe smallest unit of an element, made up of protons and neutrons in a central nucleus surrounded by moving electrons. usually have a balanced or neutral electrical charge, with an equal number of electrons (with a negative charge) and (with a positive charge). However, some electrons can be removed from atoms, creating an imbalance. The atoms that lost electrons become positively charged, while the atoms that received electrons become negatively charged.
When the charge between two objects is unbalanced, the extra electrons on the negatively charged object are drawn toward the positively charged object in order to balance the charges again. This movement of electrons is electricity....
(The entire section is 2685 words.)