Subha Das Mollick
Many students do not like physics because it is too cold and objective, devoid of emotion. To get these students interested in physics, one may try reading out passages from popular science books. Good popular science books effectively bring out the lateral thinking that scientists are capable of as well as the intellectual discipline with which they negotiate the problems. These writings bring alive a problem in physics and give it a human dimension.
Below are excerpts from two popular science books and the exercises are based on these passages. Physics teachers may try them out in class.
Excerpt from Life in Science, by Michael White, Jojn Gribbin. (Chapter 9, page 136, 137)
It was, in fact, satellite borne instruments that identified, at about this time, the first really plausible black hole candidate in our Milky Way Galaxy. Just as great new discoveries in astronomy had come about in the 1960s through the investigation of the radio part of the spectrum, at wavelengths longer than those of light, so great new advances came in the 1970s through the investigation of the X ray part of the spectrum, at wavelengths much shorter than those of light. Unlike radio waves, however, X rays from space are blocked by the earth’s atmosphere, and do not reach the ground (which is just as well or we would be fried). So X ray astronomy came of age as a branch of science only when suitable detectors were placed in orbit around the earth. These unmanned satellites transformed astronomers’ view of the universe, showing it to be a much more violent and energetic place than they had thought. And at least some of that violence, they are now convinced, is associated with black holes.
- Compare the frequency range of radio waves to that of visible light and to the frequency range of X rays.
- Why do you think X rays, that can penetrate human flesh, are blocked by the earth’s atmosphere?
- How do you think satellites with X ray detectors revealed the universe to be a much more violent place than it was earlier thought to be?
- What kind of violent activities do you think goes on in the universe?
The author is the secretary of Bichitra Pathshala, an organization that promotes learning with moving images. She is also an associate director at iLEAD Institute, Kolkata. She can be reached at