《专业英语》课件-6 final.ppt

Part 1 Course Introduction Part 2 Kinematics Part 3 Laws of Conservation Part 4 Thermodynamics Part 5 Optics Part 6 Electricity and Magnetism Special Topic Electricity Electrostatics Capacitor and capacitance Battery Electric current and electric circuit Electrical resistance Conduction of electricity, semiconductor and Superconductivity Electromagnetism rub [r?b]： 摩擦 nylon [‘nail?n] sweater：尼龙运动衫 crackle [‘kr?kl]：（使）发劈啪声 amber [‘?mb?]：琥珀 electric charge：电荷 twitch [twit?]：抽搐，抽动，阵痛 voltaic [v?l‘teiik]：伏打电池 electrochemistry [i,lektr?u‘kemistri]：电化学 electrolysis [,ilek‘tr?lisis]：电解 generator [‘d?en?reit?]：发电机 magnet [‘m?ɡnit]：磁体，磁铁 electromagnetism [i,lektr?u‘m?ɡnitiz?m]：电磁学 glow [ɡl?u]：发光，发热 relay [ri‘lei]：继电器 the triode vaccum tube：三级真空管 cathode-ray [‘k?θ?ud]：阴极射线 electromotive [i,lektr?u‘m?utiv]：电测的 Electricity is a property of nature that we usually know as electric current. We cannot see it, but we can see its effects. Rubbing two things together sometimes produces electricity. This happens when you take off a nylon sweater. The nylon rubs against your hair or your clothing. The electricity causes crackling and sparks. This effect has been known for thousands of years. A Greek philosopher called Thales noticed it in 600 B.C. (Before Christ) He rubbed a piece of amber. When he did this, the amber tried to pull things towards it. This is because it had an electric charge. This is how electricity got its name. It comes from the Greek for amber, elektron. Another effect of electricity is lightning. This was not always known. The American scientist Benjamin Franklin first showed this connection between electricity and lightning. In 1780, another effect of electricity is was noticed. An Italian named Luigi Gavlvani touched the back leg of a dead frog with his knife. When he did this, the leg twitched. He guessed that this was due to electricity. Another Italian, Count Alessandro Volta, found out what was happening. The knife