From electromagnetism to the atom

A single “D” battery can supply an astonishing 75,000 J of energy! If you could get all the energy out in one second that would be the equivalent of 100 horses, from a package that fits in the palm of your hand. Fortunately, 1.5 volt batteries can’t deliver electrical power so quickly, or they would be very unsafe. Read the text aloud What do a light bulb and lightning have in common?
Electricity exists because matter has a property called electric charge, which is normally hidden. Inside atoms are negatively charged particles called electrons and positively charged particles called protons. Under special circumstances, such as dragging your feet across a carpet on a dry winter day, you can sense electric charge in the form of a spark from static electricity. Lightning is another way to see the effects of electric charge—but hopefully not to experience it! Read the text aloud
Magnets seem to have little to do with electricity but magnetism and electricity are two faces of the same fundamental phenomenon. In the late 19th century physicists discovered that electric current can cause magnetism. Electromagnetism is the operating principle behind electric motors, generators, computer disk drives, and countless other technologies. Read the text aloud
Photograph of cutting foil into bits with scissors under a magnifying glassLight is an electromagnetic wave and it interacts with individual atoms. What is an atom? Consider cutting a piece of aluminum foil into the smallest possible bits, then using a microscope to divide those bits into smaller bits, and the smaller bits into even smaller bits, and so on. At some point you come to a single atom of aluminum, which, at 0.00000001 m in diameter, is the very smallest particle of aluminum there can be. If you divide the atom further by separating some protons, neutrons, or electrons, you will no longer have aluminum at all but some other element. Read the text aloud
When technology was developed that allowed us to actually observe how electrons and protons behaved inside atoms, and how light interacted with single atoms, we found something completely new. Quantum physics was invented to explain the universe on very small scales. It is both a crowning intellectual achievement for its accuracy at describing the world of atoms and also a profound mystery because it causes us to completely rethink almost everything we know about how the world works. An electron with a mass of 9.1 × 10−31 kg does not behave at all like a tiny marble that is simply a million trillion trillions times smaller than usual. Read the text aloud
Many technologies in use—such as the MRI scanner in a hospital or a computer—explicitly depend on quantum physics. The laser in a laser cutting machine is based on stimulated emission, which is a quantum phenomenon. The quantum world is extraordinarily rich and surprisingly not well explored. A superconducting wire that carries electricity without friction is one potential quantum technology that may become reality in the decades to come.
Electricity and magnetism are two unique phenomena that interact and affect each other. They are often referred to collectively as electromagnetism. Many technologies use the principles of electricity, magnetism, or both to transfer energy and accomplish work. Indicate whether the following technologies use electricity, magnetism, or both.
  1. compass
  2. battery-powered motor
  3. flashlight
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