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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 current has been established i...
Book Chapter
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 formation reveals to us properties...
Book Chapter
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 space. This chapter begins by tak...
Book Chapter
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 precisely, Einstein attributed an...
Book Chapter
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 obey the conservation laws. T...
Book Chapter
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 emerging from one point and focuse...
Book Chapter
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. However, this is not the only ...
Book Chapter
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 field acting on a moving charge pu...
Book Chapter
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 with altitude, and light rays be...
Book Chapter
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 physics. It then presents a challe...
Book Chapter
Every school-age kid has heard the prediction “What goes up must come down.” Many kids challenge it with a question relating to helium balloons. Some inquisitive and persistent kids have wondered what would happen if that object thrown up was g...
Book Chapter
Watching the Olympic Games is a reminder of the versatility of physics. The equations for projectile motion can be used to analyze many different track and field events. The athletes are not required to understand all of the physics, but coaches stud...
Book Chapter
All of the scenarios presented in this chapter have similar solutions. The trajectory of any object can be analyzed (without air resistance) by recognizing that the horizontal and vertical motions are independent of one another. The horizontal motion...
Book Chapter
Light plays such a crucial role in our lives that it’s very hard to imagine a universe without light. But what is light? How do we describe its behavior? We have two basic models that we can use to describe light—particle behavior and light beh...
Book Chapter
Can you keep a secret? Is it possible to send a signal out so that one person will receive the signal but another will not? The scenario presented in this chapter is a young radio amateur who maintains a link with two friends living in two towns. Two...
Book Chapter
Have you ever wanted to go to Mars? Sending humans to Mars will require a lot of preparation but the work has already begun. If you were too young to have watched the efforts to send the first humans to the Moon, you may be able to participate in th...
Book Chapter
Everyone loves colors—the colors of spring and summer, the colors of butterfly wings and rainbows, the colors of soap bubbles, and the colors from a CD. How are these the same? How are they different? Should we look to the same cause for what appea...
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What distinguishes the world’s great chefs from the millions of adequate cooks is an understanding of the concepts of cooking. We strive for a similar appreciation of physics concepts in our students. Most of the time the problems in physics textbo...
Book Chapter
A low rumble through the Earth convulses a highway like a fish gasping for air. A child in a distant playground moves gracefully propelling the swing to new heights. A crystal glass shatters with the precision of an operatic singer's voice. The Ear...
Book Chapter
Why do elephants have such big ears? And why do they have such thick legs? In other words, why do elephants have different shapes than horses? This chapter focuses on these questions and more explaining how they can be answered using the laws of scal...
Book Chapter
An interesting experiment to perform involves a helium balloon tied to the seat of a car. As the car accelerates forward, the helium balloon will lean forward. There are two distinct ways of explaining why. The first involves the inertia of the air....
Book Chapter
A very popular physics toy consists of two concave spherical mirrors facing each other like the shells of a clam. If a coin or button is placed on the surface of the lower mirror, its image appears in the hole at the center of the top mirror. The i...
Book Chapter
Merry Go-Rounds are the most egalitarian ride in that everybody can have a good time. As personal thrill tolerances increase, other rides are tried where the floor is pulled out from under you when the cylinder is spinning fast enough to “pin” yo...
Book Chapter
Millions of dollars of research and experimentation have been invested in car designs to minimize the adverse effects of air resistance. And here is the American household negating all efforts to maximize gas mileage with outdoor gear strapped to t...
Book Chapter
As a police cruiser drives by with its siren sounding, the pitch of the siren decreases. The same thing happens at the Indianapolis 500 as a race car passes you. The pitch of the engine is steady as the car approaches, decreases as the car passes, an...
Book Chapter
He’s full of hot air! We all know what this expression means. In this chapter, students of physics take a more substantial look at hot air knowing that hot air rises and is one means by which a hot-air balloon can soar above. The hot-air balloon be...
Book Chapter
Michael Jordan makes it all look so easy. The ball gracefully glides in its arc and swishes through the net. All that polish from years of practice and no formal physics. Can a mathematical approach help to replicate Jordan’s skills? Definitely not...
Book Chapter
Have you ever taken your bathroom scales to an elevator for a ride? This is guaranteed to start an interesting conversation and you will be advancing the cause of physics at the same time. This chapter features several scenarios to explore physics i...
Book Chapter
The complexity of the human eye confounded Darwin. But his concept of adaptation and natural selection guided a steady stream of biologists who have collectively depicted a series of 40 steps, each a small advantage over the prior, which describe ...
Book Chapter
We are all familiar with images formed by mirrors and lens. In fact, we often pay to see images produced in special ways. But what is an “image charge?” Does it have anything to do with optical images? This chapter presents a scenario to help a...
Book Chapter
The technological products of the discovery of fission, notably the atomic bomb and nuclear power, have greatly elevated its importance in our culture. The chore in this chapter is somewhat modest in comparison to both the science history and the po...
Book Chapter
One person described how the bedroom wall moved across the room. Another watched as a huge wave of concrete traveled along the highway. We all saw the massive destruction when one bridge roadway collapsed on top of another. The earthquake in the San...
Book Chapter
What happens when you are given a problem that is either too complex to solve or one where there are crucial ingredients missing? Many problems are very complex and cannot be solved if all the complexity is included. If, however, the problem is simp...
Book Chapter
Newton was certainly not the first person to see an apple fall from a tree. He may, however, have been the first to imagine the apple and the Moon to be one and the same. To Newton, the Moon was merely a much larger apple very much further from the ...
Book Chapter
This chapter focuses on finding the magnetic field. In the Biot-Savart law, the magnetic field is perpendicular to both the current element and the radiusvector. The magnetic field points out of the plane determined by the current element and the po...
Book Chapter
The analysis of the rolling wheel has become much simpler. The kinetic energy of the rolling wheel is equal to the rotational kinetic energy of the wheel about its center of mass plus the kinetic energy of the entire mass moving with the velocity of...
Book Chapter
Given a flashlight battery, a flashlight bulb, and a single piece of wire, hold them together to make the bulb light. Adults have taken more than an hour to light the bulb! And yet, this is the first activity in a lesson on circuit electricity for f...
Book Chapter
Visually, if not straight lines, then does nature favor curves? All curves are not equivalent. This chapter embarks on a brief tour of some simple physics with an eye toward the curves to discover along the way. ...
Book Chapter
Relativistic conservation laws
Conservation laws are everywhere! Conservation of energy is one of the most useful laws in all branches of science. Other conservation laws in physics include charge, momentum, angular momentum, and those associated with the more esoteric baryon and...
Book Chapter
How does a good theory get judged? It must first be able to explain what the prevailing theory has successfully explained. It must also be able to explain some known phenomenon that the prevailing theory is unable to explain. When that theory is abl...