Electricity is the set of physical phenomena associated with the presence and flow of electric charge. Electricity gives a wide variety of well-known effects, such as lightning, static electricity, electromagnetic induction and the flow of electrical current. In addition, electricity permits the creation and reception of electromagnetic radiation such as radio waves.
Magnetism is a property of materials that respond to an applied magnetic field. Permanent magnets have persistent magnetic fields caused by ferromagnetism. That is the strongest and most familiar type of magnetism. However, all materials are influenced varyingly by the presence of a magnetic field. Some are attracted to a magnetic field; others are repulsed by a magnetic field.
Electromagnetism is the branch of science concerned with the forces that occur between electrically charged particles. In the electromagnetic theory these forces are explained using electromagnetic fields. The electromagnetic force is one of the four fundamental interactions in nature, the other three being the strong interaction, the weak interaction and gravitation. Electromagnetism manifests as both electric fields and magnetic fields. Electric fields are the cause of several common phenomena, such as electric potential (such as the voltage of a battery) and electric current (such as the flow of electricity through a flashlight). Magnetic fields are the cause of the force associated with magnets. Both fields are simply different aspects of electromagnetism, and hence are intrinsically related. Thus, a changing electric field generates a magnetic field; conversely a changing magnetic field generates an electric field. This effect is called electromagnetic induction, and is the basis of operation for electrical generators, induction motors, and transformers.
(From www.wikipedia.org)
Task 14. Webquest. Make a list of devices that use electromagnetism. Use the Internet and research one of these devices and be ready ro report back to the group.
GRAVITATION
«Gravitation is not responsible for people falling in love».
Albert Einstein[3]
Vocabulary
| acceleration (N) – ускорение analytic ( al ) ( Adj ) – аналитический calculate ( V ) – вычислять discard ( V ) – отказываться evidence ( N ) – наглядность, доказательство, подтверждение expand ( V ) – расширять find out ( V ) – выяснять, понять force ( N ) – сила formula (N) – формулировка, формула; мн. formulae, formulas gain ( V ) – получать, приобретать gravitational pull – сила притяжения hypothesis (N) – гипотеза impact (N) – удар, толчок intersect (V) – пересекать inversely (Adv) – обратно пропорционально | point mass – точечная масса predictive (Adj) – предсказывающий proportional ( Adj ) – пропорциональный rate ( N ) – темп, скорость release ( V ) – отпускать revise ( V ) – проверять, пересматривать square (N) – квадрат statement ( N ) – утверждение support ( V ) – поддерживать the Law of Universal Gravitation – закон всемирного тяготения the Theory of General Relativity – теория относительности thoroughly ( Adv ) – полностью, основательно, тщательно |
Task 1. Discuss with a partner.
1. Do you agree or disagree with the quotation above?
2. What is gravitation? Who developed the laws of gravitation? Is gravity a law or a theory?
Task 2. Skim the text « Is Gravity a Theory or a Law? » and find the key sentence in each paragraph. Underline the sentence with the main idea of the text.
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