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"I must be the one to kill Harry Potter!"—Lord Voldemort
The time has finally come for me to write about Harry Potter. I enjoyed the books as they came out, and have seen all the films, though some have certainly been better than others. If modern fiction has any character who needs no introduction, it is Harry Potter, so I will assume everyone has some familiarity with the story.
This film presents the first half of the last book, Harry Potter and the Deathly Hallows. The evil Lord Voldemort has returned to power, and the wizarding world is still reeling from the death of Albus Dumbledore at the end of the last installment of the story. Harry, Ron, and Hermione are working to destroy the "horcruxes" in which Voldemort has stored portions of his soul in a bid for immortality. As long as any portion of Voldemort's soul survives, he could find a way to return to power. Our three heroes are on the run for much of the film, as Voldemort and his minions have control of the Ministry of Magic and Hogwarts School of Witchcraft and Wizardy. We learn about the three "deathly hallows," objects so powerful that they may enable a wizard to cheat Death. If Voldemort gains control of all three, he will likely become invincible.
This film is a young-adult fantasy full of science-defying magic spells, so some might expect me to complain about all the violations of Newton's Laws or energy conservation and leave it at that. Instead, I'd like to note that The Deathly Hallows gives Americans an excellent opportunity to see some landforms in the United Kingdom, so Earth science teachers might use some segments to show their students formations not easily found in the United States. A seemingly incidental gadget could spark a discussion about astronomy, and finally, physics teachers can revisit a concern about teleportation I discussed in my very first column.
Harry Potter on the "limestone pavements."
While on the run, Harry, Ron, and Hermione hide out in desolate corners of Great Britain. (Note: the island is Great Britain, while the United Kingdom consists of four countries: England, Scotland, Wales, and Northern Ireland. Those of us on this side of the Atlantic often find this confusing.) One of the places Harry and Hermione end up is the top of a small mountain where the rocks are flat, but divided into squares and rectangles with deep channels between them. The one in the film is probably Ewe's Top in Wales, pictured here along with other limestone pavement formations. Limestone pavement forms when a glacier removes the soil over a limestone layer, leaving it flat and exposed to the elements. Since water dissolves limestone (slowly), natural cracks and fissures are gradually deepened, eventually forming a network that looks like a cobblestone street. Pavements with shallow grooves are younger than those with deep fissures. The formation in the film is quite old, as the fissures are both deep and wide. Though a number of these formations exist in the United Kingdom and Europe, they are quite unusual in North America, so Earth science teachers could point them out to students.
As I mentioned earlier, Dumbledore (Hogwarts' headmaster and leader of the opposition to Voldemort) was killed at the end of the sixth Harry Potter story. We learn in The Deathly Hallows that he left some important items to Harry, Ron, and Hermione in his will. The most interesting to me as a physics guy is the "deluminator" willed to Ron. On clicking a button, this device collects the light from any nearby lamp and stores it. A second click releases the light and returns it to the lamp from which it came. In our "muggle" world, one object traps light: a black hole. (I am not saying that the deluminator is a black hole; it just does something similar.) Black holes are the most dense objects known to science, with gravitational fields so strong that even light cannot escape from them. Black holes are believed to be formed at the end of the life cycle of some stars, and astronomers have compelling evidence that a so-called supermassive black hole is at the center of our galaxy. A reasonable question students might have is how astronomers can see a black hole if no light gets out of one. Scientists primarily use two approaches. First, the huge mass of a black hole affects the motion of stars near it, and that can be easily observed. Second, as matter is pulled into a black hole, it releases radiation as potential energy is converted to kinetic energy. That radiation can be observed from Earth.
Another nifty bit of magic dodges a physics challenge other films have failed. Harry, Ron, and Hermione move around Britain by "apparating," a form of teleportation witches and wizards learn late in their training at Hogwarts. Of the three, Hermione is the best at this skill, so she generally takes charge of their transport from one place to another. She can take Harry and Ron along with her, as long as they are both touching her. This is quite similar to the "jumping" done by Dave, the main character in Jumper, which happens to be the first film I reviewed for Blick on Flicks.
One of my concerns about Dave's teleportation was his movement north or south on the planet. A point on the equator is moving faster than places north or south because the diameter of a circle travelled in one day shrinks the farther you are from the equator. (At the poles, you would only turn in place.) A sloppy teleport could result in your moving too quickly or too slowly for your new location. Apparating in Harry Potter is less of a problem than Dave's jumping for two reasons. First, Harry, Ron, and Hermione only move around Great Britain, so they can't travel more than five or six degrees north or south in one move, while Dave goes from London to Fiji in a single jump. The other reason, though, is more important. In Jumper, objects seemed to carry their motion with them during the jump. In Harry Potter, people are still when they are about to disappear, and motionless when they arrive at the new location. This seems more consistent to me than the conceit in Jumper, in which only the motion the screenwriters want is carried along.
Though the film is based on magic, Earth science, astronomy, and physics can be found in Harry Potter and the Deathly Hallows (Part 1).
Jacob Clark Blickenstaff is Assistant Professor of Physics and Assistant Director of the Center for Science and Mathematics Education at the University of Southern Mississippi. He can be reached at firstname.lastname@example.org.
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