<meta http-equiv="refresh" content="1; url=/nojavascript/"> Laboratory Activities for Chapter 1 | CK-12 Foundation
Dismiss
Skip Navigation
You are reading an older version of this FlexBook® textbook: Chemistry - Second Edition Teacher's Edition Go to the latest version.

1.4: Laboratory Activities for Chapter 1

Created by: CK-12
 0  0  0

Science Background Information

What is Mass-Energy Equivalence?

Albert Einstein is best known for his theories of relativity. There are two parts to the theory. The first part is the special theory of relativity, which was proposed in 1905. The second is the general theory of relativity, which was proposed in 1915. Einstein’s special theory of relativity describes the motion of particles moving close to the speed of light. Mass-energy equivalence is a consequence of the special theory of relativity. Mass-energy equivalence is the concept that a measured quantity of energy is equivalent to a measured quantity of mass. The formula E = mc^2 expresses the connection between mass and energy. Here E represents energy, m represents mass, and c represents the speed of light in a vacuum. Because the speed of light is a very large number (299,792,458 \ m/s) and it is squared, the equation shows that very small amounts of mass can be converted into very large amounts of energy and vice versa.

Rene Blondlot and N-Rays

In 1903, Rene Blondlot was a distinguished professor of physics at the University of Nancy, France. He was a member of the French Academy of Sciences and had won several scientific awards. He had designed and carried out a brilliant experiment to measure the speed of electricity traveling through a conductor. Other scientists duplicating Blondlot's methods found that the method worked and they got the same result as Blondlot. Thus, his results were verified.

Later in his career, while trying to polarize x-rays, Blondlot claimed to have discovered a new invisible radiation similar to x-rays which he called N-rays (after the town of Nancy). Blondlot claimed that N-rays were emitted by all substances except wood and he detected them with an instrument he designed using an aluminum prism to scatter the rays and a fluorescent thread to detect the rays. Fourteen of Blondlot's friends (also scientists) confirmed the existence of the N-rays. Some other scientists tried Blondlot's experimental set up and agreed with his results. The French Academy of Science was preparing to award Blondlot their highest prize, the LaLande Prize.

Dr. Robert Wood, an American scientist, attempted to reproduce Blondlot's experiment in his own lab. Not only was Wood unable to obtain Blondlot's results but some of the observations reported by Blondlot seemed to Wood to be impossible. Nature magazine was skeptical of Blondlot's result because other scientists in England and Germany were also unable to duplicate Blondlot's result. The magazine sent Dr. Wood to investigate Blondlot's discovery.

Wood visited Blondlot's lab and asked for a demonstration of the experiment. Wood looked through the eyepiece of the instrument but saw no effect of N-rays on the thread. He was told by Blondlot that his eyes weren't properly sensitized. At one point, while Blondlot and his assistant were operating the instrument, Wood secretly reached into the machine and removed the prism. Both Blondlot and his assistant, however, continued to “see” the evidence of N-rays when it was impossible for the instrument to work. Wood then tried to secretly put the prism back in place, but the assistant saw him and thought that Wood was removing the prism. The next time they ran the experiment, neither Blondlot nor the assistant could see any N-rays, even though the machine was in proper working order.

Wood published the results of his visit to Blondlot's lab and the contentions of Blondlot, his assistant, and colleagues was discredited. The French Academy of Science had already published over 100 papers about N-rays. The Academy went ahead and awarded the LaLande prize to Blondlot but it was presented as rewarding his entire career and no mention was made of N-rays. Ten years later, all mention of N-rays had been removed from French science books and French encyclopedias.

There are other similar stories - some about scientists who made serious errors in experiments and others about scientists who faked data - if you are interested in reading about some, you could search internet stories on polywater or cold fusion.

James Randi versus the Dowsers

Dowsing is the process of using wooden twigs or metal rods to locate hidden water or pieces of metal. The dowser holds the sticks or rods in his hands and when they swing together, it indicates the presence of water or metal.

With the rods in the starting position, the dowser walks across a search area and when he/she passes over underground water or a hidden piece of metal, the rods will swing together indicating the presence of water or metal.

James Randi, a former magician, who now spends his time debunking paranormal charlatans, has made a standing offer, originally \$10,000 but now \$1,000,000, to anyone who can pass controlled tests to prove they have paranormal or supernatural powers (this includes dowsing). Mr. Randi uses what are called double blind experiments to test the claims of dowsers. A double blind test requires that neither the dowser nor the judges know the position of the dowsers search object. Over 1,000 people have attempted to claim the prize money, none have succeeded.

Consider the case of Stanley Wojcik, who claimed to be an expert dowser who could locate hidden pieces of metal in over 90% of his trials. Mr. Wojcik supplied reference letters from individuals who supported his claims. Mr. Wojcik's dowsing rods were two coat hangers straightened out to form L-shaped pieces. His procedure was to proceed forward with the rods projecting straight out in front of him until some object was “sensed” and then the rods would swing together.

The test began with Mr. Wojcik being asked to locate a small pile of coins placed on a table in plain sight. This was done to show the judges how the dowsing rods behaved when locating the hidden object and to offer proof that there was nothing in the location to inhibit the function of the dowsing rods. It is common for dowsers who fail the test to offer excuses for the failure . . . the most common excuse is that there is something in the location that interfered with the test . . . like water pipes in the floor or something of that sort.

Mr. Wojcik walked around the room with the dowsing rods extended and when he reached the coins on the table, the dowsing rods came together. Then Mr. Wojcik was asked if the rods would still work if the coins were placed in an envelope and Wojcik replied in the affirmative. During the second test, when the coins were placed in an envelope and placed on the same table in the same place as before, the rods again came together precisely over the envelope. In the next dozen tests, nine more envelopes identical to the first but containing small lumps of paper to match the lump caused by the coins were placed around the room. Even though the odds would indicate that the dowser would correctly find the envelope containing the coins once in ten tries, Mr. Wojcik failed to find the coins even one time. When Mr. Wojcik indicated the test was flawed because of water pipes, the test was moved to another room and Mr. Wojcik still failed every time. The dowser had scored 100% on the trials where he could see the object and 0\% on the blind trials.

Tests such as this have been performed with many dowsers over the years, but Mr. Randi still has the \$1,000,000.

Checking the Data on the “Mysterious” Bermuda Triangle

The “Bermuda Triangle” is a triangular expanse of ocean between the three vertices of Bermuda, Puerto Rico, and Miami. The “mystery” of the Bermuda Triangle was set forth in a series of three books written by Charles Berlitz in the 1970's. Since the publication of the three books, dozens of other books, articles, stories, and several TV movies about the Bermuda Triangle have appeared.

Berlitz's books contained a collection of stories of boats, airplanes, and people mysteriously lost at sea in the Bermuda Triangle, and claimed that all the stories were true and that they offered proof that there was something strange about the Triangle. Berlitz convinced millions of people that there was some unknown force in the Triangle that caused planes, boats, and people to disappear. This unknown force has variously been attributed to a sunken flying saucer, the lost city of Atlantis, or some distortion in the earth's magnetic field.

When an unbelievable story is claimed to be true, the best place to start checking the story is to examine the data upon which the hypothesis is based.

Berlitz identified approximately 80 incidents that he claimed occurred in the Bermuda Triangle. Subsequent authors have stated that there are thousands of such incidences but do not identify any of them. Skeptics who investigated the original 80 incidents have determined that 41 of them did not occur at all. That is, there was never an airplane or boat by the name given in the story; there was never a report made to the U.S. Navy, Coast Guard; or to any police department; the people named cannot be located by the names given in the story; and there were no flight plans or travel plans filed at the airport or harbor of origination. It is presumed, therefore, that these are fictional incidents.

Of the total number of incidents claimed, only 39 have any evidence indicating that they actually took place. Of the 39, 10 were accidents in which a ship was found abandoned. Bermuda Triangle authors indicate that the people disappeared with no explanation. For these 10 cases, however, the crews were rescued and produced quite normal explanations of what happened and whly the ship was abandoned.

The other 29 incidents are indicated on the map.

Of the original 80 incidents, 41 were fictitious, 10 turned out to be quite normal, and of the 29 remaining incidents, only 4 of them actually occurred inside the Triangle. As you can see on the map, one incident occurred in the Gulf of California, over 2,000 \ miles from the Bermuda Triangle. You can also see three incidents that occurred on the European side of the Atlantic Ocean, also over 2,000 \ miles from the Triangle. These three occurred off the coast of Ireland, off the coast of Portugal, and near the Azores Islands. It is absurd to include these events in any examination of the Bermuda Triangle.

Berlitz reported incidents in his book using language and shortage of details to make the incidents seem as mysterious as possible. More complete reports often remove the mystery.

Example report by Berlitz: “Thirty-nine persons vanished north of the Triangle on a flight to Jamaica on February 2, 1953. An SOS, which ended abruptly without explanation, was sent by the British York transport just before it disappeared. No trace was ever found.”

A more complete report: The flight plan of the transport was to fly from the Azores (near Portugal) to Newfoundland, Canada. After an overnight stopover, the plane was to continue on to Jamaica the following day. On the flight to Canada, the plane encountered strong winds up to 75 \ miles per hour and torrential rains in the mid-Atlantic. The crew sent an SOS which ended abruptly and no parts of the airplane were found.

This airplane did not crash in the Bermuda Triangle, in fact, it never even flew through the Bermuda Triangle. The only connection to the Triangle was a future flight plan. When metal airplanes fall into the ocean, they sink . . . and when they sink, radio messages cease abruptly. Berlitz uses words like “vanished” and “disappeared” rather than “crashed in the ocean and sank” to make the incident seem mysterious.

Another Berlitz report: Berlitz's description of the loss of Eastern Flight 401 indicated that while flying through the Triangle, the Eastern flight “suffered a loss by disintegration”. This description would lead us to believe that the flight was somewhere in the Triangle when suddenly pieces of the airplane began to fall off for no apparent reason.

Surviving crew member's report: The crew members reported that while over the Florida Everglades (not in the Triangle), they turned off the autopilot and while trying to fix a navigation problem, failed to notice a loss in altitude. The plane flew into the ground and “disintegrated.” End of mystery.

Another Berlitz report: This incident involves Christopher Columbus. Berlitz reports in his book (and quotes from Columbus' logbook) that Columbus wrote about a “fireball which circled his flagship.”

Other readers of the logbook report: Columbus wrote of “a great flame which fell into the sea.” There is no indication or implication in Columbus' logbook that the flame circled his ship. A meteor burning through the atmosphere is a spectacular sight and somewhat rare. One that flew around in a circle would indeed be a mystery.

The primary incident that Bermuda Triangle enthusiasts would point to is an incident that occurred on December 15, 1945. According to Berlitz, five fully equipped Avenger torpedo bombers took off from Fort Lauderdale Naval Air Station on a flight into the Triangle and back. At the time the planes should have returned, the flight leader reported over the radio they were lost and confused about directions. About 45 \ minutes later, the planes vanished from radar screens. A rescue plane sent to find them also disappeared. No trace was found of either flight. Berlitz also reported some strange radio transmissions by the pilots and flight leader.

The official Naval report of the incident, however, again, is a somewhat different story. The flight was a training flight for new pilots. Only the flight leader's compass was turned on. During the flight, the flight leader's compass failed and this failure was reported by radio. The failure was discovered after the planes were dangerously low on fuel. The pilots were lost and flew around in confusion until out of fuel and then fell into the sea. The rescue plane that was sent was known to be a dangerous plane because it leaked gas fumes inside the plane. A ship in the area observed this rescue plane explode and fall into the sea. Records and witness accounts of the radio transmissions from the flight show no strange or unusual transmissions. From the official report, there appears to be no mystery. The media, however, preferred the mysterious scenario and chose not to check the facts.

The desire to see favorable results where none exist is the source of much of the “data” presented by supporters of the paranormal. There are also examples of this failing in orthodox science. To protect ourselves from such wrong-headed thinking, we must always be skeptical and when we suspect flawed procedures, CHECK THE DATA AND HOW IT WAS COLLECTED.

Historical Comparisons

Introduction to Science

What is science? Is it a list of marvelous inventions and how they work? Or is it a list of theories about matter and energy and biological systems? Or is science a subject that you learn by carrying out activities in a laboratory? Science is all of these, but it is also something even more basic. Science is a method of thinking that allows us to discover how the world around us works.

To begin this study of one form of science, we will review the last 3,000 years in the history of human transportation, communication, and medicine. The following summary lists humankind's accomplishments in these areas during three periods in the last 3,000 years.

Transportation in 1000 B.C.

In 1000 B.C., people could transport themselves and their goods by walking, riding an animal, or by riding in a cart pulled by an animal (Figure below). Crossing water, people could paddle a boat or have an animal walk beside the river and pull the boat (Figure below). These methods of transportation required muscle power, either human muscles or animal muscles.

A horse-drawn Egyptian chariot. Chariots originated in Mesopotamia around 3000 B.C.

A photo of a wooden model of a Greek ship that has both sails and oars.

A photo of a wooden model of a Greek ship that has both sails and oars.

A few societies had designed rowboats or sailboats, which used muscle power or the force of the wind to move the boat. These early means of transportation were very limited in terms of speed and therefore, also limited in terms of distances traveled. The sail and rowboats were used on rivers and inland seas, but were not ocean-going vessels.

Transportation in 1830

By the year 1830, people were still walking and riding in carts pulled by animals. Iron ore was moved along canals by animals pulling barges. American pioneers crossed the United States in covered wagons pulled by animals (Figure below). Large cities had streetcars pulled by horses (Figure below). Ocean crossing was accomplished in sailing ships. The only improvement in transportation was the addition of springs and padded seats to carts and wagons to make the ride less jolting. In the period from 1000 B.C. to 1830, a span of 2,830 years (about 100 generations of people), there were no significant changes in the mode of human transportation.

A covered wagon of the type used by pioneers to cross the US in the mid-1800s.

The first horse-drawn street car in Seattle, Washington in 1884.

The first horse-drawn street car in Seattle, Washington in 1884.

Transportation in 1995

By the year 1995, steam engines, gasoline engines, automobiles, propeller-driven and jet engines, locomotives, nuclear-powered ships, and inter-planetary rocket ships were invented (Figure below). In all industrialized countries, almost anyone could own an automobile and travel great distances in very short times.

In the mid-1800s, several months were required to travel from Missouri to California by covered wagon and the trip was made at considerable risk to the traveler's life. In 1995, an average family could travel this same distance easily in two days and in relative safety. An ordinary person in 1995 probably traveled a greater distance in one year than an ordinary person in 1830 did in an entire lifetime. The significant changes in the means of transportation in the 165 years between 1830 and 1995 (perhaps 5 generations) were phenomenal.

A modern jetliner.

A modern jetliner.

Communication in 1000 B.C.

Shopping list chiseled on a rock.

Shopping list chiseled on a rock.

Essentially, people's only means of communicating over large distances (more than 15 miles) in 1000 B.C. was to send hand-carried messages (Figure above). Some societies, for short distances, had developed the use of smoke signals, light signals, or drum signals, but these methods were useless for long distances. Since the means of communicating required hand-carried messages, the speed of communication was limited by the speed of transportation. Sending messages over distances of 1,000 miles could require several weeks and even then delivery was not guaranteed.

Communication in 1830

A pony express rider, circa 1861.

A pony express rider, circa 1861.

By the year 1830, people's means of communication over large distances was still the hand-carried message. While the paper and ink used to write the message had been improved, it still had to be hand-carried. In the United States, communication between New York and San Francisco required more than a month. When a new president was elected, Californians would not know who it was for a couple of months after the election.

For a short period of time, the Pony Express was set up and could deliver a letter from St. Louis, Missouri to Sacramento, California in eleven days, which was amazing at the time (Figure above). The means of communication in 1830 was essentially the same as in 1000 B.C.

Communication in 1995

A modern cell phone.

A modern cell phone.

By the year 1995, the telegraph, telephone, radio, television, optical fibers, and communication satellites were invented (Figure above). People could communicate almost anywhere in the industrialized world instantaneously. Now, when a U.S. president is elected, people around the globe know the name of the new president the instant the last vote is counted. Astronauts communicate directly between the earth and the moon. An ordinary person in an industrialized country can speak with people around the world while simultaneously watching events occur in real time globally. There have been truly extraordinary changes in people's ability to communicate in the last 165 years.

Medical Treatment in 1000 B.C.

Physician letting blood from a patient.

Physician letting blood from a patient.

Medical treatment in 1000 B.C. consisted of a few natural herbs and some superstitious chants and dances. The most advanced societies used both sorcerers and herbalists for medical treatment. Some of the natural herbs helped the patient and some did not. Cleaning and bandaging wounds decreased opportunity for infection while some herbs such as sesame oil demonstrated moderate antiseptic properties. Dances, chants, incense burning, and magic spells were absolutely useless in curing illnesses. At some point in time, bloodletting was added to the physician's repertoire (Figure above). Bloodletting was accomplished by cutting the patient and allowing the blood to drip out or by applying leeches (which doctors often carried with them). However, bloodletting was not helpful to the patient, and in many cases, it was harmful. Bloodletting was flourishing by 500 B.C. and was carried out by both surgeons and barbers. It wasn't until around 1875 that bloodletting was established as quackery.

In those times, for an ordinary person, broken bones went unset and injuries like deep cuts or stab wounds were often fatal due to infection. Infant mortality was high and it was common for at least one child in a family die before adulthood. The death of the mother in childbirth was also quite common.

In the Middle Ages, knowledge of germs, hygiene, and contagion was non-existent. People who were seriously ill might have their disease blamed on the planets going out of line (astrology) or "bad odors," or retribution for sins, or an imbalance in body fluids. Cures could involve anything from magic spells, bleeding, sweating, and vomiting to re-balance bodily fluids. Between 1340 AD and 1348 AD, the Black Death (bubonic plague) was responsible for killing in the vicinity of half the population of Europe. The bacterium causing the disease was carried by fleas, but, of course, none of this was known by the physicians of the time. Efforts to stop the plague included burning incense to eliminate "bad odors," causing loud noises to chase the plague away (the constant ringing of bells or firing of canon), and a number of people used self-flagellation to attempt to cure the disease.

Medical Treatment in 1830

Medical treatment in 1830 remained in the form of natural herbs and bloodletting. During this time, the ability to set broken bones and to amputate limbs was also developed. Amputation saved many lives from infection and gangrene. Gangrene occurs when the blood supply to tissue is interrupted and the tissue dies. The dead tissue remains part of the body, invites infection, and causes death as the poisons from the rotting tissue are carried through the body. Once gangrene afflicted an arm or leg, the poison from the limb would eventually kill the patient. During the American Civil War (1861 - 1863), a common means of treatment for wounds in field hospitals was amputation. Along with amputation was the ability to cauterize wounds to stop bleeding.

Even though bloodletting did not help patients, it continued in use through 1830. There is a tale (which may or may not be true) that George Washington was suffering from pneumonia and his doctors removed so much blood trying to cure him that they actually caused his death.

Medical Treatment in 1995

Receiving a vaccination.

Receiving a vaccination.

By 1995, medical science had discovered chemical medicines, antiseptic procedures, surgery, and probably most important of all, vaccination . . . the ability to prevent disease rather than cure it after it had been contracted (Figure above).

Diseases that had killed and crippled hundreds of thousands of people in the past are seldom heard of today (polio, smallpox, cholera, bubonic plague, etc.). These diseases have been controlled by scientific understanding of their causes and carriers and by vaccination. Average life expectancy has nearly doubled in the last 165 years. Both infant mortality and death during childbirth rates have dropped to less than 25 \% of what they were in 1830.

Methods of Learning About Nature: Opinion, Authority, and Superstition

Why did humans make so little progress in the 2,800 years before 1830 and then such incredible progress in the 160 years after 1830?

Socrates (469 B.C. - 399 B.C.), Plato (427 B.C. - 347 B.C.), and Aristotle (384 B.C. - 322 B.C.) are among the most famous of the Greek philosophers. Plato was a student of Socrates and Aristotle was a student of Plato. These three were probably the greatest thinkers of their time. Aristotle's views on physical science profoundly shaped medieval scholarship and his influence extended into the Renaissance (14^{th} century). Aristotle's opinions were the authority on nature until well into the 1300s.

Unfortunately, many of Aristotle's opinions were wrong. It is not intended here to denigrate Aristotle's intelligence; he was without doubt a brilliant man. It was simply that he was using a method for determining the nature of the physical world that is inadequate for that task. The philosopher's method was logical thinking, not making observations on the natural world. This led to many errors in Aristotle's thinking on nature. Let's consider just two of Aristotle's opinions as examples.

In Aristotle's opinion, men were bigger and stronger than women, and therefore, it was logical that men would have more teeth than women. Therefore, Aristotle concluded it was a true fact that men had more teeth than women. Apparently, it never entered his mind to actually look into the mouths of both genders and count their teeth. Had he done so, he would have found that men and women have exactly the same number of teeth.

In terms of physical science, Aristotle thought about dropping two balls of exactly the same size and shape but of different masses to see which one would strike the ground first. In his mind, it was clear that the heavier ball would fall faster than the lighter one and he concluded that this was a law of nature. Once again, he did not consider doing an experiment to see which ball fell faster. It was logical to him, and in fact, it still seems logical. If someone told you that the heavier ball would fall faster, you would have no reason to disbelieve it. In fact, it is not true and the best way to prove this is to try it. Eighteen centuries later, Galileo decided to actually get two balls of different masses, but with the same size and shape, and drop them off a building (legend says the Leaning Tower of Pisa), and actually see which one hit the ground first. When Galileo actually did the experiment, he discovered, by observation, that the two balls hit the ground at exactly the same time . . . Aristotle's opinion was, once again, wrong.

In the 16^{th} and 17^{th} centuries, innovative thinkers were developing a new way to discover the nature of the world around them. They were developing a method that relied upon making observations of phenomena and insisting that their explanations of the nature of the phenomena corresponded to the observations they made. In order to do this, they had to overcome the opinions of the ancient Greeks, the authority of the church, and the superstitions of ordinary people.

In the opinion of the ancient Greeks, the earth was the center of the universe and did not move, while the sun, moon, planets, and stars revolved around the Earth in orbits. The astronomer Ptolemy (around 150 A.D.) observed the positions of the planets and recognized that the positions where he observed the planets did not match up with the positions predicted by the orbits of the Greeks. Ptolemy designed new orbits that had circles within circles and complicated retrograde motion (planets moving backward in their orbits at certain times). His descriptions came closer but still could not accurately predict where the heavenly orbs would be on a given night. It wasn't until Nicolaus Copernicus (1473 - 1543) suggested a heliocentric (sun-centered) system that the positions of the planets came close to matching predictions. Copernicus was hesitant to publish his ideas - some say because he feared ridicule from his peers and others say because he feared persecution by the church - but eventually, he sent his work for publication just before his death.

The publication of Copernicus' heliocentric theory didn't seem to cause much controversy for the next 50 years until the idea was supported by a scientist named Giordano Bruno who was promptly prosecuted and burned at the stake by Cardinal Bellarmini in 1600. The most famous supporter of the Copernican system was Galileo Galilei (1564 - 1642) who had developed an improved telescope (1610) and turned it toward the sky. Galileo published a small work describing what he saw with his telescope and how his observations supported the Copernican theory. The book was banned by the church in 1616 and Galileo was instructed not to write about the subject any further. In 1632, Galileo published another work, again supporting the Copernican theory and was arrested by the church, prosecuted, and punished by house arrest for the remainder of his life.

But the method of learning by experimenting, observing, and hypothesizing had been launched and many scientists would not turn back. It should be mentioned that the supporters of the methods of opinion, authority, and superstition did not give and have not given up today. We still have “scientists” claiming that unsupported opinions are “facts” and we still have people deciding the “truth” about nature by voting on it. Nor has superstition died. You may remember from your history classes that the pilgrims of Massachusetts were still drowning and hanging women accused of being witches as late as 1693. It is easy to think that the people of those times were not very smart, and nowadays, no one would think that way. However, you should be aware that a student was suspended from school in Tulsa, Oklahoma in 1999 for “casting spells” and a substitute teacher in Florida was fired in 2008 for “wizardry” after performing a magic trick for his students.

Image Attributions

Files can only be attached to the latest version of None

Reviews

Please wait...
Please wait...
Image Detail
Sizes: Medium | Original
 
CK.SCI.ENG.TE.2.Chemistry.1.4

Original text