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Iron is solid, mercury is liquid, and nitrogen is a gas. Liquid nitrogen is used to perform lots of interesting and fun experiments. Demonstrations exploiting the extreme cold of liquid nitrogen provide entertainment…
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How can someone levitate an object? Magicians do it all the time. Can physicists do it as well? The easiest technique is to attach a string to the object and secure the string to the ceiling. The weight of the object is…
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“It’s done with mirrors.” Whether we attend magic shows or ride the “Haunted Mansion,” we are often surprised and pleased by clever manipulations of images. This chapter looks at the image produced by a concave mirror…
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Supposedly young people are first introduced to waves while attending or watching sports events. These stadium waves can provide some useful insights into the most counterintuitive property of waves—the wave moves, but…
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The motion of simple pendulums has played an interesting role in physics and technology. The simplest pendulum to study would probably be a compact mass attached to a long string. Physicists call this “the simple…
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For those of us who grew up with conventional electromagnets, it is very strange to see an electromagnet that is not connected to an external power source. But that is what happens with a superconducting magnet. After a…
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It seems almost counterintuitive that wet air should be less dense than dry air and float in the sky. But the beauty of the cirrus and cumulus attest to this as we gaze at the myriad shapes and forms above us. Cloud…
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Medical questions were very important during the Skylab mission from May 1973 until February 1974. At the most basic level the scientists wanted to know if the astronauts would lose weight during prolonged stays in…
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In what now seems like physics folklore, the young patent clerk Albert Einstein proposed that light behaves like a particle—known as a photon—and that each photon has an energy that depends on its frequency. More…
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Although Isaac Newton probably never bowled a perfect 300 game, his physics can be used to analyze the sport of bowling. The collision of the ball with the bowling pins—and the collisions of the pins themselves—must…
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A converging lens bends all rays of light parallel to the principal axis (the axis of symmetry of the lens) in such a way that they converge at a single point referred to as the focus. The lens also takes the light…
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Edwin Hubble showed that most stars (and galaxies) are receding from Earth. Because of the expansion, the frequencies of the spectral lines from the stars are shifted to lower values—that is, the light is redshifted.…
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When we think of forces, we usually imagine a push or a pull. Such a push or pull is assumed to be in the direction of the line connecting the pusher and the object pushed. Not so with the Lorentz force. A magnetic…
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Nature has exhibited the effects of a variable index of refraction for a very long time. The index of refraction of air varies with its density. Therefore, the index of refraction of the Earth’s atmosphere decreases…
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Hos fast can you throw a baseball? How fast is a speeding bullet? Restricted to simple tools in the laboratory, this chapter explains how both measurements can be completed with a clever approach and some elementary…
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