Physics of History

Course No. 1252
Professor David J. Helfand, Ph.D.
Columbia University
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Course No. 1252
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Course Overview

In April 1991, two Alpine hikers stumbled across the well-preserved body of a Copper Age hunter half-buried in a glacier on the border between Italy and Austria. This accidental discovery, nicknamed Ötzi the Iceman, possessed a trove of invaluable information about the origins of prehistoric people. Yet while standard archaeological techniques revealed many interesting aspects of Ötzi's life—including his diet and his dress—it was only through the use of physics that more microscopic clues were uncovered; clues that, decades earlier, might have remained hidden. The strontium-to-lead ratios in Ötzi's teeth matched the ratios found in the Eisack Valley, northeast of present-day Bolzano, Italy, suggesting that was where he spent his childhood. Varying ratios of oxygen 18 to oxygen 16 in Ötzi's bones indicated that he spent much of his later life at higher altitudes. And the presence of excess copper and arsenic in Ötzi's hair suggested that he played an active role in copper smelting.

This is but one of the many examples of how the laws of physics can give us intimate details about history—details that are impossible to find through mere observation. In fact, the history of the entire universe and all it contains is written in the particular arrangements of the fundamental particles that constitute all matter. With recent developments in technology, scientists can now use everything they know about atoms—their origins, structure, and behavior—to uncover the truth about historical mysteries in archaeology, chemistry, geology, astronomy, and even art.

With this unprecedented access to times far earlier than those recorded by historians, scientists can now explore the rise and fall of preliterate societies, the history of the Earth's changing climate, and even the origins of the solar system 4.5 billion years ago. Using this knowledge, they can finally develop a comprehensive, stable timeline that encompasses all of history, from the beginning of time to today—all by "reading" the history of a bone, a piece of wood, the mortar in a building, a neutrino from the sun, and more.

The Physics of History, taught by award-winning Professor David J. Helfand of Columbia University, gives you the background to understand how scientists know what they do about the past. These 24 richly illustrated lectures cover an astonishing range of cases in which physics has helped to redefine history—in astronomy, archaeology, geology, climatology, art history, and other fields.

An Amazing Voyage

Your amazing voyage begins with five lectures on elementary atomic and nuclear physics. Professor Helfand then builds on this background with a series of lectures dealing with mysteries on Earth. He rounds out the course with a group of lectures that take on the problems of the cosmos, including the radical adjustment in our view of time and space required by Einstein's theory of relativity.

Immensely rewarding and enlightening, The Physics of History enhances your appreciation of both science and history by addressing questions such as these:

  • How did corn spread across the New World? Knowing the photosynthetic pathway used by corn, scientists can analyze Native American bones and chart the spread of corn cultivation, from its origin in the highlands of Mexico to New England over the course of 7,000 years.
  • When did the extinction of the dinosaurs occur? Scientists have been able to narrow down June as the month when, 64.5 million years ago, an asteroid slammed into the Yucatan peninsula and wiped out at least 50% of all living species on Earth—all from a frozen water lily leaf preserved at a particular point in its life cycle.
  • Which is older, Stonehenge or the pyramids? Archaeologists long considered Stonehenge to be much younger than the Egyptian pyramids. But in the 1960s, carbon-14 dating showed Stonehenge to be much older, predating the pyramids by hundreds of years.
  • How old is the Earth? Analysis of a pair of rare atoms in meteorites shows that the Earth and the rest of the solar system formed 4.56 billion years ago. Clues in atoms also tell scientists about the early history of the Earth, where the moon came from, and that the explosion of a nearby star may have triggered the formation of the sun and planets.

Tools of the Trade

In The Physics of History, you explore the resources that scientists use to investigate the past, the most important of which is radioactivity. Radioactive isotopes decay at predictable rates, from fractions of a second to billions of years, making them very precise clocks. Isotopes also serve as tracers for the circumstances that produced them, such as the explosion of a star.

One of the best-known radioactive isotopes is carbon-14. With a half-life of 5,730 years (the time required for half of the atoms to decay), it is ideal for dating carbon-containing material relating to human history. For example, the carbonate mortar in an unusual tower in Rhode Island turned out to be only 300 years old, showing that it was not built by the Vikings before Columbus, as some people believed.

You also examine other tools, many of which are used in combination:

  • Tree rings: These annual growth layers have been compiled into a continuous record extending back 12,000 years, allowing wood to be dated from distinctive patterns of ring widths, which also contain information on the weather conditions for any given year.
  • Ice cores: With ice sheets more than two miles thick, Greenland and Antarctica preserve the successive snowfalls of 750,000 years. Trapped in these layers are atmospheric gases, sea salt, and dust, which serve as time capsules of long-ago events.
  • Ocean sediments: Extending even further back than tree rings or ice cores, ocean sediments represent a continuous 5-million-year record, shedding light on climate change and continental drift.

Drama, Mystery, and Delight

One of the pleasures of The Physics of History is watching Professor Helfand tackle each of his case histories like a detective at a crime scene, using an arsenal of techniques to tease vivid stories from the slimmest of evidence. The drama and delight of his teaching style have made him a popular lecturer at Columbia University, where he was honored with a Presidential Teaching Award and a Great Teacher Award from the Society of Columbia Graduates.

Among the many mysteries you solve with him are these:

  • How to use atoms in a work of art to show whether it is a fake
  • Why a simple ratio of isotopes can signal if orange juice has been adulterated with corn syrup
  • What created the left-handed asymmetry in amino acids found in all forms of life on Earth, as well as in meteorites

The Physics of History is an insightful feast that will undoubtedly satisfy your curiosity about some of the most profound discoveries in the history of humanity—and the universe. With the wealth of information contained in this course, the next time you hear about a breakthrough scientific finding in the news, you'll be better equipped to answer the question: How did they do that?

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24 lectures
 |  Average 30 minutes each
  • 1
    The Vast Reaches of Time and Space
    Atoms tell the story of events that are inaccessible to the methods of traditional historians. Begin your study of this hidden history by investigating simple analogies that allow you to comprehend the vast realms of time and space that are covered in the course. x
  • 2
    Fundamentally, What's the World Made Of?
    Everything is made of atoms, but what are atoms made of? In this lecture, peel back their layers, discovering that the atomic nucleus can serve as an invaluable clock and that electrons behave in distinctive ways that identify atoms across millions of light-years of space. x
  • 3
    Energy in the Atomic World
    Investigate the forces through which atoms and their particles interact. These interactions are manifested as energy. As an example, you tally the human requirement for energy at the atomic level, coming up with an average of about 2,000 calories per person, per day. x
  • 4
    The Atomic Basis of the Senses
    Professor Helfand shows how your sensations are mediated by a cascade of atomic interactions, starting in the external world and ending in the brain. For all their power, the senses miss a great deal; for instance, there's a good evolutionary reason why your nose can't detect carbon monoxide. x
  • 5
    Radioactivity—Nature's Imperturbable Clock
    It is impossible to say when something happened without a clock to measure the passage of time. Learn that for a wide range of time scales, nature provides imperturbable clocks in the radioactive decay of different isotopes. x
  • 6
    From Detecting Forgeries to the First Art
    Discover that by bombarding a painting with neutrons, it's possible to determine the pigments employed. If you find modern pigments that were not in use when the work was supposedly created, then you know something is amiss. Carbon-14 dating is another technique for unmasking forgeries. x
  • 7
    Watching Plaster Dry—And Dating It
    Carbon-14 decay is ideal for dating material that was once alive, or indeed for any chemical process that involves carbon. In this lecture, learn how this technique helped debunk a story about the Vikings in Rhode Island. x
  • 8
    We Are What We Eat—The History of Diet
    Since every atom in your body comes from consuming and inhaling atoms, a detailed analysis of your atomic makeup says quite a lot about you. Investigate the ancient Iceman, whose probable birthplace and subsequent wanderings are revealed in the atoms of his bones and hair. x
  • 9
    A Plant Is What It Eats—Tracing Agriculture
    Investigate three separate biochemical pathways for photosynthesis. Thanks to the pathway that evolved for drought tolerance in plants such as corn, scientists are able to chart the ancient spread of corn cultivation from Mexico to New England over the course of 7,000 years. x
  • 10
    Tree Rings—Seasons of the Past 12,000 Years
    Leonardo da Vinci pioneered the idea of reading past seasons in tree rings. However, the field did not take off until the 20th century. This lecture shows how isotopic analysis of tree rings yields records of temperature and humidity, year by year, for a dozen millennia. x
  • 11
    Ice Cores—Climate Records for 800 Millennia
    Remarkably, an ice core provides all the records of a modern weather station, extending over a time interval five times longer than humans have inhabited the Earth. Study past periods of climate change and the lessons they hold for today's warming planet. x
  • 12
    Ocean Sediments Reveal 5 Million Years
    Explore another archive of information: ocean sediments. As sea plants and animals die and sink to the ocean floor, their remains preserve the isotopic ratios of oxygen and hydrogen present when they were alive, providing a continuous record of sea-surface temperatures over millions of years. x
  • 13
    A Bad Day in June—Death of the Dinosaurs
    One of the most celebrated incidents of prehistory is the asteroid impact that led to the extinction of the dinosaurs. Follow the trail of evidence that helped investigators deduce the time, place, and outcome of this Earth-shaking event, which paved the way for the rise of mammals. x
  • 14
    The Origin and Early History of Life
    Life emerged on Earth from commonplace interstellar chemicals. Look at the early history of life, including the peculiar fact that the amino acids on Earth and in meteorites are left-handed, a situation that may relate to the violent effects of a nearby neutron star. x
  • 15
    The History of Earth's Atmosphere
    Clues from other planets and from the geological record allow scientists to reconstruct the long-term history of Earth's atmosphere and the dramatic differences in climate over time. Learn why dragonflies with 30-inch wingspans were possible in the distant past but not today. x
  • 16
    The Age of the Solar System
    In this lecture, look at historical estimates for the age of Earth and the solar system. Thanks to a pair of rare atoms, we now know the answer: 4.56 billion years. Analysis of moon rocks adds further details about cataclysms that shaped the early Earth. x
  • 17
    What Happened before the Sun Was Born?
    Here, investigate how an isotope found in meteorites suggests that a massive star blew up in the region that later saw the formation of the solar system. This blast may have provided the push that a localized cloud of gas needed to collapse and form the sun. x
  • 18
    Atoms Are Star Stuff—Cooking Up Carbon
    What is a star? Professor Helfand makes sense of the astronomer's definition: "A star is a plasma, gravitationally bound, supported by thermal pressure in hydrostatic equilibrium (usually), emitting blackbody radiation, and powered by nuclear fusion." x
  • 19
    The Lives of Big Stars—Cooking Up Big Atoms
    All that you eat, except for hydrogen atoms, was cooked for you inside stars. Explore why this is so and investigate the life cycles of stars of different masses and how all the elements from carbon to uranium are forged inside them. x
  • 20
    Relativity—Space and Time Become Spacetime
    Moving beyond the Milky Way galaxy, examine the surprising relationship between space and time discovered by Einstein. An understanding of his theory of relativity is crucial for the course's final quest to explain the origin of matter at the beginning of time. x
  • 21
    (Almost) Everything Is Relative
    The finite speed of light and the constancy of this speed for all observers is the basis for Einstein's special theory of relativity. Explore some consequences of the theory, such as the time dilation effect, which makes two clocks run at different rates depending on their relative motion. x
  • 22
    Matter Vanishes; Light Speed Is Breached?
    Relativity does not forbid faster-than-light travel, however, the strange consequences of such a phenomenon have never been observed. Discover how, in a world with theoretical faster-than-light particles, an effect could precede its cause in time. Also, learn about the equivalence of mass and energy. x
  • 23
    The Limits of Vision—13.7 Billion Years Ago
    Continuing your journey to the beginning of time, look back to the origin of the cosmic microwave background, a universal glow that permeates all of space and that records the state of the universe just 380,000 years after the big bang. x
  • 24
    The First Few Minutes—Where It All Began
    Arrive at the events that gave rise to matter itself. Professor Helfand likens this early period to an extreme form of musical chairs, when fundamental particles "froze out" at different times. End the course by following the history of a single quark, from its birth to its surprising fate today. x

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Video DVD
DVD Includes:
  • 24 lectures on 4 DVDs
  • 152-page printed course guidebook

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Course Guidebook Details:
  • 152-page printed course guidebook
  • Suggested readings
  • Questions to consider
  • Timeline

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Your professor

David J. Helfand

About Your Professor

David J. Helfand, Ph.D.
Columbia University
Dr. David J. Helfand is Professor of Astronomy at Columbia University, where he has taught for over 30 years. He was an undergraduate at Amherst College and earned his Ph.D. in Astronomy from the University of Massachusetts, Amherst, where he worked under Professor Joseph Taylor, the 1993 Nobel Laureate in Physics. Professor Helfand's research has covered many areas of modern astrophysics, including radio, optical, and...
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Physics of History is rated 4.5 out of 5 by 74.
Rated 5 out of 5 by from The Physics of History I am a physician (retired) and have time to learn in areas outside of my speciality. This course has been truely eye opening for me, far beyond any expectations I may have had. He made me think. I was continually going on line to better understand many of the concepts, not because he doen't explain things extremely well, but because this covers lots of ground. I feel I have a better qualitative understanding of the fundamental forcesand their interactions with particles. Concepts of space-time and their relationship to mass and energy were cleverely described. Even the origin of the universe and the well described particles with a nice time line were explaned with insights into how this was determined. Obviously there was lots about isotope dating, how it works, and problems of interpretation. This expands into the formation of the universe and our solar system, as well as helping to date historical events. My thanks to Dr. Helfand for months of enjoyment. He takes you about as far as you can go without being fluent in higher math. I am not niave to science, and this was a science course, but anyone can enjoy this if they make the effort.
Date published: 2013-06-30
Rated 5 out of 5 by from An Interesting Presentation of Atomic History I enjoyed Prof. Helfand's presentation of Atomic history. I think it is important to remember that he holds this course out as science for students of the humanities. Therefore, students who are more inclined to science might want to take one of TTC's more rigorous courses such as "Cosmology" or "Astronomy." But, students who do not want such a rigorous scientific treatment will probably be quite happy with this course. I enjoyed Prof. Helfand's presentation. He has a quirkly sense of humor that worked well. His course guide was also helpful in following the lectures. I particularly enjoyed how he tied everything back to the atom. I thought this was an interesting approach to the material. I also enjoyed his description (in the last ten minutes of the course) of the life cycle of a sub-atomic particle from the Big Bang to the present. As alluded to above, I would recommend this course for students who are interested in physics and astronomy, but who do not want the scientific rigor of a course like "Astronomy" or "Cosmology." Otherwise, a thoroughly enjoyable course.
Date published: 2013-04-28
Rated 5 out of 5 by from Outstanding! Professor Helfand is an outstanding lecturer. He knows his material, has a great voice, speaks with authority, and explains concepts in a clear, concise manner. His use of humor, frequently self- deprecating, lightens the sometimes heavy course material. This course is indeed a physics course…not a history course. Insofar as” history” in the usual meaning of the word is covered, it is the history of scientific discoveries and the scientists involved…and there are frequent asides in that regard. Essentially, this course explains how science dates history from the relatively recent past back to the origins of the universe. ..and how science determines past climate, agriculture, diets, etc. With the exception of a few sections on tree rings, ocean sediments, etc., it relies heavily on atomic physics. Don’t let the words “atomic physics” scare you…we’re talking basic concepts here…mainly atomic structure and energy transfer. Helfand does an excellent job of explaining the understanding needed in the first few lectures. Little math is involved and, when it is, it is mainly multiplication and division and it is done for you. However, you’ll likely find the material comes at you fast and hard. This is not a criticism of Helfand’s presentation, as he explains things well. It is simply that there is a lot of material to absorb here. Unless you have a good understanding of atomic physics, my advice is to plan on repeating lectures 1 through 5 and especially, 2,3, and 5 until you understand these concepts before moving on to the remaining lectures. You’ll need to know the structure of atoms, what isotopes and radioactive decay are, how atoms combine to form molecules, energy transfer, etc. Without that understanding, the remaining courses will simply tell you what atoms science uses to determine dates, climate, etc. but you will lack understanding of the process. For example, you’ll know science uses carbon 14 to date organic material from the relatively recent past (something you likely already knew), but you won’t have a true understanding of how science does it and why it works…or even what carbon 14 is. Lectures 16 through 24 take us to time predating the earth…to the dating and formation of our solar system, the universe, and the very atoms which make up our material world. The lectures cover a significant amount of astronomy in the process and take us back to the very beginning of time itself. I have a degree in atmospheric physics which I earned some 40+ years ago. This course served as an excellent review of basic atomic physics as well as expanding that knowledge into the new world of quarks, leptons, etc. However, Helfand does such a great job of explaining this material that I do not feel a physics background is a prerequisite to the course. If you don’t have that background, just plan to review the early lectures where necessary…listen to what Professor Helfand has to say…and you’ll get it. I highly recommended “The Physics of History” to anyone with an interest in the subject matter. After taking it, you’ll understand how science is able to accomplish such things as determining art forgeries, how old a human skeleton is…his or her diet and where they were likely born, when a structure was built, how old a rock is, what the climate was like thousands of years ago…and on and on. Its well worth a second trip through it…and I plan to do so. An outstanding job in all aspects!
Date published: 2013-03-02
Rated 5 out of 5 by from Physics of History This is an excellent science course, repleted with well presented knowledge that should be well received by science lovers. But I also agree with one of the previous reviewer that, in actual, you cannot learn a lot unless you delve deep in to atomic science especially on isotopes. A small suggestion for those who start with the course, if I may, is to go to lecture 24 after the lecture 1 then come back and start with lecture 2. That appears to me more logical in grasping the content.
Date published: 2013-02-21
Rated 5 out of 5 by from Excellent Science Course This course is very well written. It is logically organized, presents its subject matter clearly early on in an interesting way. It does an excellent job building on items discussed in previous lectures. As a science buff with little technical training I found this course both interesting and educational. Professor Helfand has a style that is easy to listen to and follow. Not getting too bogged down in what we don't know but at the same time being fair in areas where there is still uncertainty. What I loved the most about this course was the logical foundation and building how of scientists know what they know about the past. I now have a much deeper understanding of how various dating techniques work and an appreciation for the confidence they can express in how old something is. I was delighted and surprised to have several lectures that provided me with a non-partisan understanding of climate change and the history of earths climate fluctuations. I recommend this course for both those who enjoy history and wonder how we know what we know. I also recommend it for those who enjoy science and want to build their big picture foundation of how we can speak with confidence about 64 million years ago or even 3.7 billion years ago.
Date published: 2013-02-17
Rated 5 out of 5 by from Greatest of all the Great Courses I was entirely rapt throughout - except the 5 minutes of advanced math which were a tiny bit over my head.
Date published: 2012-12-28
Rated 5 out of 5 by from Worthwhile Investment This course provides a terrific "snap shot" picture of the connectedness of all matter. In this course, Dr Halfand step by step, properly accounts for all the key past events in the Universe and how what we see today in the nature of the components of matter are the result of processes that trace all the way back to "The Big Bang". If you ever wanted to have a good feel for the "Big Picture" of how the physical world became what it is today and why it and its components behave the way they do (and much more), I certainly recommend this course! :-)
Date published: 2012-10-23
Rated 2 out of 5 by from Interesting Misfire It's not easy to come up with a just appraisal of this course. The presentation is crisp, disciplined and authoritative. Helfand has mastered a vast brief and he goes about his work with enthusiasm. Yet it is hard to imagine what by way of real learning anybody takes away from it. The overall effect is a bit like drinking from a firehouse. One would at least have to listen two or three times. To get any real learning, one would have to spend a lot of time actually trying to work through the material on one's own--problem sets, maybe discussion sections. Lacking that, one is bound to end up more with the illusion of learning than with any real content. [IIdle aside: has TC given any thought to trying to partner with Khan Academy?] Footnote: the "history" label is perverse, almost certainly misleading. Grant that it may present a record of how particular physical phenomena changed over time, still if "history" is a record of what people have done or suffered, then this is nothing of the sort. It perhaps seems perverse to fix such a low rating on such an impressive effort. And grant that some people are bound to love it. But tastes differ, and inquirers need to know at least that they will encounter an offering for a specialized taste.
Date published: 2012-08-04
Rated 4 out of 5 by from Very interesting As a non-scientist this was an area that I had not ventured into before and I was very pleasantly surprised at the ease with which Professor Helfand put across quite complex ideas and information that stuck in my mind after each lecture had finished. However there were times when I had to watch a second time particularly when we reached the astronomy/cosmology sections towards the end. All in all an enjoyable experience with the Professor coming across as a 'kindly uncle' in his approach albeit a very knowledgeable one!
Date published: 2012-05-17
Rated 5 out of 5 by from Pleasantly Different Professor Helfand is a top notch lecturer and this course, too, is a top notch course. But do not assume it is a course on "The Physics of History; for it is more, muich more. It is better described as a nuclear physics course on Natural History and Cosmological History. I imagine that the Teaching Company is trying to produce courses that are NOT simply copies of college and university courses; but instead, freshly different, pleasantly different, new-perspective, multi-discipline courses that are a pleasure to view, all the while delivering the goods too. Such is this course; showing how the structure of the lowly atom can be used for detecting and examining almost everything; from detecting art forgeries and dating archeological grave goods to ascertaining the history and age of the universe. If you are intellectually curious and an information sponge on widely diverse scientific topics you will enjoy Prof. Helfand's wry sense of humor, his crystal-clear lecture style and the presented material in this wonderfully pleasant and quite different "atomic" level approach to Natural and Cosmological History.
Date published: 2012-04-22
Rated 5 out of 5 by from Crystal clear explanations of nearly everything This course is not what I expected, nor what Dr. Helfand indicated it would be in the first few of lectures. But who cares! It is so much more than a course on the physics of history, although it does that very well. Dr, Helfand provides wonderfully clear explanations on a huge range of topics; everything from our perception of colors to the big bang. He really shines when it comes to physics and cosmology, including the life cycles of stars, subatomic particles, and relativity. In fact, his explanation of special relativity is the first one I've encountered that really made sense to me. Past explanations simply left me confused; Dr. Helfand's explanation left me awestruck - and quite disturbed! One reason that Dr. Helfand's explanations are so clear is that they are supported by wonderful graphics. The graphics were clearly designed specifically for the course, which makes them much more effective than those of many Teaching Company courses, which often give the impression of having been selected from some pre-existing grab-bag by someone other than the course instructor. Finally. Dr. Helfand provides an engaging delivery with a sparking sense of humor. I loved this course!
Date published: 2012-03-05
Rated 5 out of 5 by from Stretched my brain but I enjoyed it! I know very little about physics and astronomy but I love history so thought I would give this a try-what fun! I admit there were a few lectures I had to listen to twice to be sure I was following the thread, but the professor is so entertaining I really didn't mind! I learned a lot about atomic stuff and was interested because of the history context. The guidebook was very helpful. It was good for me to read the outline before listening to the class. I would recommend this for anyone who has only a basic understanding of chemistry and physics and wants to stretch their brain!
Date published: 2012-01-27
Rated 2 out of 5 by from A Cosmic Disappointment I was especially disappointed in this course after reading the majority of the viewer reviews which were overwhelmingly positive. My expectation was for a course which utilized physics to analyze and explore history. This approach actually comprises a very small part of the course - such as the explanation for dating art history and dating archeological sites. The entire second half of the course devolved into cosmology - and approached it by going backwards, culminating in the Big Bang! I found the whole course to be disorganized and thematically incoherent - with extensive sidetracking such as analyzing the human organs of perception. Professor Hefland himself generated neither positive nor negative emotions from his presentation - it was neither engaging or annoying - just bland. I have viewed many of the TC's courses on physics and astronomy - and without exception, every other course was more on topic, presented more clearly, and with a logical and coherent flow between topics. This is one of the very few courses that I will be returning.
Date published: 2011-11-14
Rated 5 out of 5 by from Very pleasant surprise I expected isotope dating of archeological sites, but this was much more. Dr Helfand gives a short and excellent introduction to physics in general and a cosmology course as well. Dr Helfand (who would make a great Santa Claus at Christmas time) has a slightly quirky style. He is however an enthusiastic and effective teacher. If you have no background in physics; some of the subject matter moves quickly. Dr Hazan's course JOY OF SCIENCE, would make an excellent prerequisite. I give this a very strong buy recommendation.
Date published: 2011-01-22
Rated 5 out of 5 by from Brilliant Professor Helfand's erudition and subtle humor combine to provide a highly instructive and entertaining lecture series. Highly recommended for everyone.
Date published: 2010-09-16
Rated 5 out of 5 by from A work of art - clearly explains modern physics This is my first Teaching Company purchase and I am 100% satisfied. Having a fairly extensive background in physics, over the years I have spent considerable time trying to understand concepts that escaped me while in college and grad school, especially in the area of quantum mechanics and relativity. What attracted me to this course (an ad in NYT Book Review caught my attention), was the breadth of material that the course promised to address from our physical senses to environmental topics, such as climate/atmosphere, geological evolution of the earth's surface, origins of the solar system, origins of the stars and galaxies, and finally an explanation of "big bang science". In addition, all the above material was to be brought together using the principles of atomic and nuclear physics, which is what originally stimulated my interest in physics in college. After receiving the course materials, I was sold by the end of lecture 2, where Dr. Helfand had successfully synthesized the 4 major forces, and particularly explained the weak and strong nuclear forces, neutrinos, and quarks, which are extremely difficult to find comprehensible representations. Lecture 3 includes a brilliant description of energy in terms of a model of heat based simply on the motions of particles, which is nothing new, of course, but Prof Helfand presents it in a way whereby it can be actually used to clearly explain physical phenomena, such as why you can reach into a hot oven of high temp, but you better not touch anything solid. There was one "issue" I had, that popped up in lecture 22, "Matter Vanishes; Light Speed is Breached?", where Dr. Helfand introduces the subject by saying "the innumerable crackpots who send me their theories of the universe each year are united by 1 conviction: that things can travel faster than the speed of light. I shall now attempt to use Dr. Helfand's own method described in lecture 20, that "By showing that one's model is incorrect, one makes progress in understanding the universe." A couple of summers ago, I was trying to really get into relativity in order make sense of some of Dirac's work. In the process, I came to the remarkable conclusion that one can, in fact, travel faster than the speed of light, which is contrary to all I had been taught, and the notion that this is impossible is taken as such a fundamental truth, that respected lecturers feel free to refer to anyone who thinks otherwise as a "crackpot". Well, how did I come to the conclusion that one can travel faster than the speed of light? Remarkably, I can use Dr. Helfland's own examples from lecture 22 to prove the point. Theory: one can travel faster than the speed of light. Proof by example: one member of a pair of twins here on Earth travels to Betelgeuse, which is 400 light years from Earth and returns for a trip where the total distance traveled is 800 light years. The travelling twin, as Dr. Helfand describes, travels at 99.9% the speed of light, and completes the round trip in 36 years. Meanwhile, his unfortunate twin who remained on Earth passed away long ago, as 800 years have elapsed on Earth. Yet, the travelling twin, who set out from Earth to Betelgeuse, an 800 light year round trip, completed his journey in 36 years, which means that he was travelling at 800/36 = 22.22 times the speed of light. QED. A couple of side notes: if the travelling twin is concerned about his brother, then his brother should take a trip of his own at a similar speed and then he will be able to reunite with his brother. Another example was also given by Dr. Helfand of the muons in lecture 21, which need to travel 100 times the speed of light to reach the surface of the Earth before they decay. What is the problem here? First, as Dr. Helfand implicitly reveals, the real speed of light is actually infinite, as described in lecture 22, where it is stated that the photons that arrive here from the "edge of space and time' have made a 13.7 billion light year journey, while "no time has elapsed for them at all". The number we call the "speed of light", 300,000 km/sec, is actually just a number that can be achieved by reaching the speed necessary for you to travel one light year in one year, which is roughly 99% of that, say, 297,000 km/sec. There is a fundamental difference between the notion of travelling faster than the "speed of light" vs travelling faster than light, itself, which because it is infinite, I agree is impossible.
Date published: 2010-08-30
Rated 5 out of 5 by from Imaginative, Rigorous and Enthralling Professor Helfand’s lecture style is exceptionally engaging. He explains background material in a way that kept me interested because it is compact and clear. He quickly builds a foundation to move to more difficult subject matter and explains concepts that were new to me in an equally intuitive, straightforward manner. His use of illustrative props for the expanding universe and the red shift are particularly imaginative. In short, he improves understanding of both the simple and the complex. His explanation of the history and evidence leading to the understanding of Dinosaur extinction is a particularly valuable case study of the scientific method. He shows how serendipity played a major role in one of the great discoveries of the 20th century. A simple but unexpected observation by a scientist looking for something else gave birth to a somewhat outlandish but plausible theory. But Professor Helfand doesn’t stop there, he shows that the real scientific work was testing this theory by every means imaginable, including many of the nuclear science techniques that he describes. Each investigation was designed to test the theory against some alternative and had the possibility of a negative result. The important lesson is that only such a rigorous search for disconfirming evidence can make a theory go from widespread skepticism to universal acceptance. All this in a half hour lecture… fantastic!
Date published: 2010-07-18
Rated 5 out of 5 by from Feels like falling in love I have just finished an amazing adventure with Dr. Helfand. Much of what he said was light years beyond my comprehension level.....but what I did "get" put tears in my eyes with one ah ha moment after another. Mostly it is the realization of things I've never given a thought to, a mind bending awareness of the nature of the world. I'm going to go back and watch it all again. I am delighted, facinated, enriched, and enlivened. It feels exactly like falling in love, but much smarter!
Date published: 2010-05-31
Rated 2 out of 5 by from Not what I expected This would be a good course for someone with no knowledge of physics or someone who is a scientist who wants a science review with brief mentions of how the topics are applied in the study of history. I had hoped for a course that would would explore, for example, a particular artifact or historical question, or archeological site and show how various techniques from physics were used to analyze the issue at hand in depth. Instead it is really an in depth review of physics concepts that are useful for historians and archeologists with very little history or archeology. From my point of view a course emphasizing the history would have been better. Also far too much on climate (global history in a sense) and warming which are addressed in other courses the Teaching Company offers. Of the 80 courses I have this is the only disappointment.
Date published: 2010-05-10
Rated 5 out of 5 by from Perfect fit for me I have always had a fascination with the physical sciences and majored in those subjects back in the 60's. The broad scope of this course, unencumbered by the daunting metaphors of higher mathematics or the excessive use of scientific vernacular, provides a great benefit to those of us who are seeking to find new horizons to explore. The professor is easy to relate to, and he shows an enjoyable enthusiasm to the variety of linked subjects in the presentation. Because of this course, I have decided to go further in my studies of modern physics, cosmology and mathematics - with an enthusiasm I thought was no longer possible. Good job, Professor Helfand.
Date published: 2010-04-13
Rated 2 out of 5 by from Disappointed We really wanted to like this course but found we could not. There were three basic problems with this course from our perspective. First, the course is not what we thought it would be. We thought, based on the product description, that it would be using the principles of physics to explore and explain history. Instead, "physics" was limited to nuclear physics (e.g., isotopes, quantum mechanics) with none of the more familiar classical physics that we expected it would include. Second, the course itself is rather incoherent. The first dozen or so lectures are all similar in that they involve isotopic analysis that leads to insights about the history of the earth; but the last 10 or so lectures move on to the history of the universe and adopt a very different (and to us, quite tedious) tone. While we understand the organizing principle of the course, we found it never really gelled. Finally, Prof. Helfand just isn't very interesting to watch. He never really seemed comfortable in front of the camera, and his lecture style, while injected with occasional humor, was not very fluid or engaging. (Sorry, Prof. Helfand.) The only reason we are not returning this course is because we may want to reference some of the material from the first half of the course (e.g., the archaeological use of isotopes) at some point in the future.
Date published: 2010-04-12
Rated 2 out of 5 by from A Dissent - Very Basic, Not Very Interesting I find myself alone among reviewers up to now, but I did not find this a worthwhile course. - The science presented is at a very basic level. Anyone with even a rudimentary layman's understanding of atomic theory, relativity, and astrophysics will learn nothing new. - Those who know nothing of these areas will learn little. Instead I highly recommend the Teaching Company's courses on astrophysics, relativity, and particle physics, all excellent. (Alex Filippenko's course "Understanding the Universe" is my choice for the most outstanding and wonderful of all of the TC's courses.) - Others apparently also found the application of the science to "history" to be of interest. I did not. This consisted of numerous unconnected applications of atomic theory (and later, relativity) to everything from dating archeological finds to detecting art forgeries to determining the age of the earth to understanding the earliest events after the Big Bang. - These are certainly fascinating areas - but here they are each considered (understandably because of time constraints) very briefly and superficially. Again, I would instead highly recommend the courses with comprehensive treatment of the relevant areas. - Perhaps the only topic covered in this course which would not be found in the other TC offerings is a technical consideration of the specific way in which the science is applied to the problem of estimating dates. But even here the discussions are wanting in detail. Simply Googling "radioactive dating" would give you a much more satisfactory review of this area. - Less important, but striking, is the low number and poor quality of the visual aids. The TC seems to be relying instead on Prof. Helfand's energetic and enthusiastic use of hand gestures to explain the physics. This is very endearing, but not quite as effective as high quality visuals would have been. But, again - I am clearly in the minority, at least among those who have taken the time to review this course. If you do take it, please add your thoughts as well.
Date published: 2010-03-01
Rated 5 out of 5 by from WayCoolParticleForensScientsts,aFewMissedOps4Grphc Absolutely fascinating material is in this course. Isotope ratios (stable and radioactive) I personally find to be fascinating -- especially in how they can be the forensic scientists inhabiting the material so you can't fool someone (art forgeries) or so you know when's and where's and thus history of the person or thing. The professor also does a good review of chemistry and physics of the particles doing their "forensic talking." The organization is a bit more hodge-podge than the typical teaching company course, but the main reason presentation went from 5 to 4 stars (I'd really give it 4.5) is that I think there were missed opportunities for both perspective-building and summarizing graphics. This course is rather numerical, as well as conceptual. So somewhat like some of the larger "ads" in the catalog for this course, the course itself should have built some perspective-building graphics and some summarizing graphics. The course "screamed" for those. Also, occassionaly, the reasoning of the forensic scientist particles became a bit intricate. To slow things down at those times, a graphic might have been useful (as well as helping those persons for whom a picture is needed to really get some of the more intricate logic). But the presenter was excellent aside from these "missed graphics" criticisms. And you get a superb understanding of particle physics and chemistry from this course -- so that alone is a nice bonus that you might not know would be in the course. But definitely the material itself is "way-cool".
Date published: 2010-02-04
Rated 4 out of 5 by from Expanding the Envelope The Physics of History is quite an ambitious course, and I feel the Teaching Company has really expanded its envelope a bit in producing it. It can get quite technical, not quantitatively of course, but conceptually, and David Helfand certainly informs us of these complex notions at light-speed in some of his lectures. Now this brisk pace of delivery is fine really, since repeated viewings will allow one to get their money's worth, after all. Yet on the flip side of that, it can all get to a point that in order to really understand many of the numerous concepts put forward in such an enormous undertaking for 24 lectures, other material must be consulted. In that way it's a survey course really, necessarily light on content due to the wide-range of subject matter. Yet perhaps that's one of the goals of such a course is to get one interested and inspired enough, to actually make use the bibliography! I suppose a parallel can be drawn between this course and successful book of Bill Bryson's, "A Short History of Nearly Everything." For that matter, I also see many similarities with many other TTC courses, so it's a bit of "everything," all centered around telling how the "tales of atomic detection-work" has allowed us to uncover a bit of human history and of the cosmos itself. I liked how the course seemed to not only describe the technical side of the detective work, such as how radioactive dating techniques work in general, but then following through by also demonstrating how it makes a difference in real-world discoveries which significantly added to our knowledge of human history. That type of connection, between pure science and the humanities, was really made compelling in a few memorable instances. Unfortunately that human element seemed to get lost in the noise as the course went onward, so that it turned more into just trying to follow the technical storyline, rather than emphasizing how these advances make a difference to us. Now I believe they do make a difference, and that the scientific-awe is certainly palpable, etc. Yet viewers who don't already believe that, might not be so motivated to finish the course unless they are already interested in the scientific techniques and can follow the jargon. That is, I'm not sure it will win over any coverts, like it appeared that it could in its earlier parts. I guess that's all part of the risk when creating more advanced courses? One example of that, is the times when David Helfand appears to sound like a news anchor, reading the teleprompter at high speed, without really explaining it to an audience that might really need to learn these concepts, not just recall them. So it can appear as if he's talking to people who already know the material, and expects them to keep up with him. Now some lecturers naturally do a better job than others, at reading teleprompters, but David is average at best in that respect. Granted also that any college professor is going to have that side to them, and David doesn't appear to be overly pedantic, but he knows the material inside-out, and can sometimes present it without appearing to hear himself think, as if he could do it in his sleep! My example here would be Robert Hazen, whose scientific lectures never fail to be delivered in a manner that simply conveys his pure fascination and enthusiasm with the topic. As far as expanding the envelope though, I see it as a welcome step in the right direction for TTC, in creating a more technically-oriented course, which specializes in presenting material to clientele who want a more advanced presentation in a field they are already familiar with or interested in. Only a few courses seem to be at this advanced level, and I would place The Physics of History, right up there in that category. So I welcome this as a new trend, instead of one like this every few years. Now the course did make adequate use of graphics when necessary, and with such advanced concepts, the graphics were critical in fact. Yet there were times when it was simply a quick and dirty description of aspects that really required more time and graphics in order to gain an in-depth understanding. Perhaps it's expected to happen, with so much to cover. Not everything can have high-tech graphics, but it sure makes things easier to perceive, and isn't that the whole point? Personally I would really like to see David Helfand return and give a course that is focused on a narrower subject, than this type of survey course. He is a very likeable professor, with a good sense of humor, though a bit dry. He ends the course with a marvelous personal history of an up quark, as it evolves from the big bang onwards, up to being exhaled in David's own breath. That gives you an idea of the daunting scope of the course.
Date published: 2010-01-24
Rated 5 out of 5 by from Physics of History Great Course! Professor David J. Helfand’s presentation is clear and well organized. For those desiring to gain understanding of a global view from the cosmos to our own way of functioning at the microcosmic level (via atomic interactions) this is one of the most informative course to be purchased from The Teaching Company. I highly recommend this course, and its accompanying transcripts for those that, like me, need the teachers to speak slower. I am grateful to the Teaching Co. for their great educational service. Humanity needs affordable education.
Date published: 2009-11-16
Rated 5 out of 5 by from EXCELLENT PROFESSOR As I am not a science person, I was a little wary about buying the course, but am glad I did. Doctor Helfand is an excellent professor who expertly uses analogies and other devices to develop his points and he maintains continuity throughout the course, building on previous ideas. Often he is dealing with complex ideas and associations, but he breaks them down into understandable components and adds timely touches of humor to keep the viewer engaged. I did find the first few lectures a little slow going, but once the foundation for the course was established, it proved to be very interesting. The applications and uses of Carbon and Uranium dating was informative, and the lectures on the extinction of the dinosaurs were outstanding. This was a worthwhile purchase that a non-science person can enjoy.
Date published: 2009-10-27
Rated 5 out of 5 by from Physics as a detective science Professor Helfand takes us, in 23.5 lectures, on a journey back through time to the moment of the big bang, tracing and dating stuff from elements to molecules to atoms to sub-atomic particles. Then in a flash he reverses the process and takes us from the big bang to the present by way of following the life-cycle of a single quark. I was reminded of the quote from Oliver Wendell Holmes, "Man's mind, once stretched by a new idea, never regains its original dimensions." During this incredible journey we encounter and grapple with dimensions vast and infinte, in size, speed, and temperature. It felt as if my mind was being pulled by the same forces which created the universe. The universe is so big and my boat is so small. And yet, I am made up of the most complex material the universe has been able to create up to this point in 13.7 billion years. The broader your background is in particle physics the more you will get from these lectures. Professor Helfand goes into atomic detail showing proofs for how scientific detectives can date prehistoric occurrences. The visual aids make complex concepts understandable and Professor Helfand's presentation keeps an interesting topic thoroughly engaging.
Date published: 2009-10-19
Rated 5 out of 5 by from A must see In the 30 years since graduating from college I am amazed at not only how far physics has come but also how certain physicists are that what they theorize is correct. This course is a must see for anyone who is at all interested in learning about the physics of the universe on the atomic level.
Date published: 2009-10-17
Rated 5 out of 5 by from Physics of History / Physics This course is advertised as being the physics of history, not the history of physics. In this course you will learn the physics involved in determining what things have happened in the past. You will learn what carbon 14 dating is along with many ways it can give incorrect results if you don't make the necessary corrections. You will also find out that carbon 14 is just one of many ways of dating a material that we employ. Somewhere in the course (half way?) it transitions from being the physics of history to just physics. The physics of the big bang and of the 14 billion years that follow are discussed. You should just think of this as bonus material. Professor Helfand explains things in novel ways. I always appreciate new perspectives. I give Professor Helfand an A+ for this work.
Date published: 2009-07-13
Rated 5 out of 5 by from Physics of History - Dr. Helfand Dr. Helfand gives a fantastic presentation with pictures and math and explains everything in minute detail. I don't have the science background or the math, but I thoroughly enjoyed his presentation. I particularly liked his presentation about the sun about what it is made up of and how it works. I like the sun. I often wondered how it could burn in an environment in space with no oxygen. It is by way of nuclear fusion that it burns and lights up. It is not a ball of fire which would require oxygen. In another three lessons, Dr. Helfand gets into a discussion of Einstein's conception of time and relativity. At times it sounds transcendental to my layman's perceptions. However, I've read articles in some science magazines that discuss whether the conception of time itself may not exist. If that means a life without alarm clocks down here on earth in our finite existence, that sounds great! In another lesson, Dr. Helfand goes into an explanation of how we've located more suns with planets rotating around them. He states that, you can tell by a planet's wobble and the way it eclipses against its sun to determine if there is a planet out there like our own. We have to tell by the wobble and the eclipse since we cannot exactly go there to the other end of the universe and have a closer look. He states that this year in 2009, the United States will be sending up a special satellite to search specifically for a planet like earth, of course from a distance like the Hubble spacecraft. Dr. Helfand gives an excellent presentation for the trained professional or the lay person because he explains every little detail of everything including the math, if you pay close attention to it.
Date published: 2009-06-19
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