The Doctor Bones Science Column
Science Questions and Answers for Elementary and Middle School Kids
As featured in the Goshen Independent (Goshen, NY)
Introducing “Ask Doctor Bones”
SCIENCE Q & A FOR ELEMENTARY AND MIDDLE SCHOOL KIDS
Doctor Bones (aka Don R.Mueller, Ph.D.-Scientist) will do his best to answer your questions from the World of Science. Questions addressing all of the Natural Sciences (i.e., Biology, Chemistry and Physics) and related topics are welcome. Did you ever want to know how something works, or why something in science is the way it is? Give Doctor Bones a try!
Do you have a question for Doctor Bones?
 _Send Doctor Bones your Science Questions:
Write me a note: 
Email:__ docbones@drbonesshow.com_________________drmueller@optonline.net
See some of the Science Questions that Kids have submitted:
October 9, 2002 _Goshen Independent
Jimmy writes: Hey Doctor Bones,________________
Question: How come an airplane can fly, even though it weighs much more than a bird?
Answer: Hi Jimmy: That’s a good question! At first glance it doesn’t seem that such a heavy object like an airplane could fly, but like a bird an airplane can create enough “lift” for it to overcome its own weight (due to gravity) to get off the ground and fly. To create lift the airplane must be moving forward. The airplane’s engine produces the “thrust,” which is the forward force acting on the airplane that is used to create lift. The thrust must also be great enough to overcome the force of the resistance from the air, a frictional force we call “drag.” Both the main wing and the tail wing of the airplane are designed to produce lift. The main wing and the tail wing are both known as “airfoils.” Airfoils or wings generally have a curve (also called the “camber”) to both their top and bottom surfaces. This curvature can be designed so that as the airplane moves forward, the air moves faster across the top of the wing than it does across the bottom of the wing. The faster moving air across the top of the wing creates a lower pressure above the wing and the slower moving air across the bottom of the wing creates a higher pressure below the wing, which lifts the airplane into the sky. This result can be explained by Bernoulli's principle, which was conceived by Daniel Bernoulli, an 18th-century Swiss scientist (1700 – 1782). Bernoulli found that a fluid, like air for example, exerts less pressure when it is moving quickly than when it is moving slowly. You can test this out at home. Take a strip of writing paper, about 2 or 3 inches wide and about 5 or 6 inches long and hold the short side between your index finger and thumb of both hands. Now blow across the top of the paper. The air moving across the top of the paper will be moving faster than it is across the bottom of the paper and the paper will lift into the air. Once you stop blowing it will fall back to its original position. You have just demonstrated to yourself how an airplane wing can be used to create flight. Can an airplane fly upside down? It sure can! The lift needed to keep the airplane flying will result as long as the front edge of the wing is tilted far enough above the rear edge of the wing. Therefore, it really doesn't matter whether the top of the wing or the bottom of the wing is facing up.
October 23, 2002 _Goshen Independent
Lisa writes: Dear Doctor Bones,____ ___ Zap !!!
Question: When I walk across the carpet and touch the doorknob, sometimes I get a shock, but other times I don’t get a shock, why is that?
Answer: Dear Lisa: I know what you mean. When you rub your shoes across the carpet, surface electrons from the carpet can move to your shoes. The soles of your shoes and the carpet are usually good electrical insulators, which also means that they are both poor conductors of electricity. As a result, when you rub them together an electrical charge can be built up. In scientific language, this means that when your shoes touch the carpet, electrons on the surface of the carpet can move or “tunnel” as its called, through the potential barrier on the surface of your shoes, thus building up a charge. The carpet loses electrons and becomes more positively charged and your shoes gain electrons and you become more negatively charged. The more rubbing you do between you and the carpet, the greater the movement of electrons and the greater the charge you will have before you touch the doorknob. Of course, when you touch the doorknob you discharge (Zap!) the electrical charge that you have built up and sometimes you can even see a small spark. However, like you said, sometimes when you walk across the carpet you don’t get a shock. Well, one reason may be because the two insulating materials (the carpet and the soles of your shoes) have not been rubbed together enough for a sufficient charge to build, and noticeable zap to occur. Another reason concerns the moisture content of the surrounding air. Dry air is a poor conductor of electricity, whereas damp air, which has a higher percentage of water vapor, is a little bit better in conducting electricity. If the air is moist, the charge building on your shoes can discharge into the air before you touch the doorknob and get zapped. Smoke particles in the air can also discharge the excess electrical charge on your shoes.
November 6, 2002 _Goshen Independent
Jennifer writes: Dear Doctor Bones,__________
Question: My little brother is always cracking his knuckles, which drives me crazy! I tried cracking my knuckles just to see why he likes it so much. Sometimes my knuckles crack, but sometimes they don’t. Why is that?
Answer: Dear Jennifer: I agree with you, little brothers can be a handful. What really happens when you “crack” your knuckles? Well, to answer this question, let’s start at the knuckle. A knuckle is any finger joint; a joint being the place where two bones meet. { Did you ever hear the joke: “What did the one bone say to the other bone? The answer is “I’ll meet you at the joint.” Ha! Ha! } The joint contains a thick, clear lubricant called synovial fluid, which helps the joint move smoothly in addition to supplying nutrients and oxygen to the joint. In the process of “cracking your knuckles” you are pulling the two bones apart at the joint, which increases the volume (space) of the joint capsule. By increasing this space, the synovial fluid pressure decreases. Dissolved gases in the synovial fluid (like nitrogen and carbon dioxide) start to leave the fluid, forming tiny bubbles, which expand and quickly burst, resulting in the familiar “popping” or “cracking” sound that we hear. The formation of gas bubbles and their subsequent collapse, produces cavities or holes in the fluid. This process is called “cavitation.” It will take time for these gases to dissolve again into the synovial fluid, which is why we can’t keep cracking our knuckles over and over again. So as you pointed out, sometimes you can crack your knuckles, while other times you can’t crack them. Does cracking your knuckles lead to arthritis? Although frequent knuckle-crackers can potentially injure themselves, there are no convincing studies to suggest that knuckle cracking leads to osteoarthritis. In any case, I agree with you, knuckle cracking is annoying!
November 20, 2002 _Goshen Independent
Joe writes: Dear Doctor Bones,____
Question: Is a hot-air balloon the same thing as a helium balloon?
Answer: Dear Joe: Although a hot-air balloon and a helium balloon are not one and the same they do work by the same simple principle, which states that: an object with a density that is less than the density of air will float upward in air. The density (d) in this case, is a measure of the mass (m) of the gas divided by its volume (V) such that d = m/V. A helium-filled balloon rises in air because the density of helium gas is about 7 times less than the density of air at sea level. A hot-air balloon also rises in air because hot air is less dense than cooler air. The use of a hot-air balloon as a lighter-than-air ship goes back a long way. In fact, in 1783, the Montgolfier Brothers used their hot-air balloon (carrying a few small farm animals) to show King Louis XVI and Marie Antoinette that such flight was possible. Shortly thereafter, a science teacher named Pilatre de Rozier, and Marquis d'Arlandes, an infantry officer, were the first people to fly in a hot-air balloon. The two of them flew for about 5.5 miles over Paris, France. A hot-air balloon has three basic parts: a balloon, a wicker basket to carry passengers and a burner assembly to heat the air. The air is heated by burning propane fuel, the same type of propane that your dad might use for a summer barbecue. Heating the air in the balloon to about 100 degrees Celsius expands the air and forces about ¼ of the original air to exit through the bottom of the balloon, decreasing the mass of gas in the balloon. The resulting hot air, which is less dense than the cooler air surrounding the balloon, doesn’t escape as readily from the bottom of the balloon because buoyancy (which means the power to float or rise in a fluid) acts to buoy it upward. Buoyancy was discovered by the Greek scientist Archimedes while he was floating around in his bathtub. Archimedes’ principle when applied to air suggests that a hot-air balloon floating in air will be buoyed up with a force equal to the weight of the air displaced by the hot-air balloon. Since the hot air in the balloon is less dense than the same volume of atmospheric air it displaces (to displace means to take the place of) the buoyant force will push the balloon upward. Helium balloons also work by the same principle of buoyancy. It is also interesting to point out that the density of hydrogen gas is about 14 times less than the density of air at sea level, which would make hydrogen an excellent gas for lighter-than-air balloons. The problem with hydrogen gas is that it burns easily in oxygen gas when someone lights a match or makes a spark. Helium balloons are used instead because helium is not combustible like hydrogen.
November 27, 2002 _Goshen Independent
Patty writes: Hello Doctor Bones,________
Question: My mom told me that if I eat a lot of turkey on Thanksgiving, I’ll get sleepy. Why is that?
Answer: Dear Patty: Happy Thanksgiving! Turkey meat contains an amino acid called “tryptophan” (pronounced “trip-toe-fan”). [Amino acids are the building blocks of proteins.] Tryptophan may be obtained from a number of plant and animal proteins. Tryptophan is used to make a chemical messenger called “serotonin” (pronounced “se-ro-toe-nin”), which is a neurotransmitter (“neuro” means “nerve”) used in the brain that can calm us and also make us feel sleepy. Neurotransmitters like serotonin are chemical substances (molecules) that allow neurons (single nerve cells) in the brain to send messages back and forth. Communication between a message sending neuron and a message receiving neuron takes place in a small gap between the two neurons called a “synapse” (pronounced “syn-apz”). Transfer of the nerve impulse across the synapse will depend upon the release of a specific neurotransmitter (like serotonin, for example) from the message sending neuron. Tryptophan is just one of a number of amino acids we will find circulating in our blood upon digesting our Thanksgiving meal. As a result, tryptophan must compete with other amino acids as they pass from the bloodstream to the brain. How then can tryptophan stand apart from the other amino acids? Well, most Thanksgiving meals are high in carbohydrates, with items like turkey stuffing, mashed potatoes and pumpkin pie on the menu. Eating carbohydrates stimulates the release of insulin into the blood, which moves many of the amino acid competitors of tryptophan out of the blood. Tryptophan is more likely to remain in the blood (and therefore move to the brain) because of its attachment to a carrier molecule. Many scientists and nutritionists who have studied tryptophan and its connection to Thanksgiving, believe that the sleepiness you feel after ingesting a Thanksgiving meal is more a result of the size of the meal (and possible alcohol usage) and the fact that more blood (and hence oxygen) is needed for digestion, than from the conversion of tryptophan to the sleep-inducing serotonin. Save me a piece of pumpkin pie!
 This is the molecular structure of the essential amino acid Tryptophan. The black spheres represent carbon atoms, red is oxygen, blue is nitrogen and the white spheres are hydrogen atoms. Amino acids are the building-blocks of proteins.
December 18, 2002 _Goshen Independent
Vanessa writes: Dear Doctor Bones,
Question: I’m in 6th grade science and I like it. There are a lot of famous men scientists, but not a lot of famous women scientists. Can you tell me about some famous women scientists?
Answer: Dear Vanessa: Science can be defined as “the knowledge gained by systematic study.” As you observed, male scientists have dominated the natural sciences (i.e. biology, chemistry and physics). However, you may be pleasantly surprised to hear that from the earliest days, female scientists have made significant contributions to the natural sciences. Clearly, women possess the same intellectual gifts as men to study science at its highest levels, but they have not entered the natural sciences in the same numbers as men. This is unfortunate, as alluded to by Dr. Rosalyn S. Yalow (in 1977 became the first American-born woman to win a Nobel Prize in Physiology or Medicine) who stated, "The world cannot afford the loss of the talents of half its people if we are to solve the many problems which beset us." Perhaps you will be inspired to become a scientist by knowing that “famous” women scientists like Marie Curie, her daughter Irène Joliot-Curie, Rachel Carson and Dorothy Crowfoot Hodgkin are just a few of the many woman scientists who have contributed greatly to science. Marie Curie (1867-1934) is perhaps the most famous woman scientist. Along with her husband Pierre, she discovered the radioactive elements, polonium and radium. She won a Nobel Prize in Physics in 1903 and a Nobel Prize in Chemistry in 1911. Madame Curie, as she was known, coined the word, “radioactive.” Irène Joliot-Curie (1897-1956), whose research contributed greatly to the study of natural and artificial radioactivity, shared the Nobel Prize for Chemistry in 1935, along with her husband Frédéric Joliot. Ecologist, Rachel Carson (1907-1964), whose book “Silent Spring” opened our eyes to the dangers that may arise from the use of pesticides like DDT on food crops, remains inspirational to future generations in protecting the natural world. Dorothy Crowfoot Hodgkin’s (1910-1994), interest in crystals as a young girl, led to a distinguished scientific career and a Nobel Prize in Chemistry in 1964. She used techniques in X-ray crystallography to determine the three-dimensional structure of important molecules like penicillin, vitamin B-12 and insulin. Try the book by Sharon Bertsch McGrayne called, “Nobel Prize Women in Science: Their Lives, Struggles, and Momentous Discoveries” for more “famous” women scientists. Bye.
___
__Madame Curie
January 8, 2003 _Goshen Independent
___________________________________________Red Blood Cells
Joey writes: Dear Doctor Bones,_____________
Question: My doctor told me that I have type-O blood. What does that mean?
Answer: Dear Joey: The ABO human blood-typing system that doctors and nurses use today originated from the blood classification research of the Austrian scientist Karl Landsteiner (1868-1943) who was awarded the Nobel Prize for Physiology or Medicine in 1930, for this important work. Dr. Landsteiner classified human blood into four major blood types: A, B, AB, and O. This lettering scheme refers to the particular antigens attached to the surface of red blood cells. [Red blood cells can be abbreviated as RBC’s.] Antigens determine blood type. Blood type-A for example, refers to A antigens, whereas type-B blood pertains to B antigens. Type-AB blood has both A and B antigens on the surface of RBC’s. People with type-O blood, have neither A antigens, nor B antigens. Antigens (short for “antibody response generating”) are also called “agglutinogens” and are complex molecules usually proteins or glycoproteins (“glyco” meaning sugar). If a particular antigen is present on the RBC surface, then an opposing antibody may be present in the blood. For example, people with blood type-A have anti-type-B antibodies, and those with type-B blood have anti-type-A antibodies. People with type-AB blood have neither anti-type-A nor anti-type-B antibodies, and people with type-O blood have both anti-type-A and anti-type-B antibodies in their blood. Antibodies (also called agglutinins) are large proteins that can bind to antigens on RBC’s thus triggering an immune response. In the case of an improperly matched blood transfusion, such an antigen-antibody response can be that of RBC’s clumping together, which is known as a “transfusion reaction.” To avoid a transfusion reaction, those giving blood (donors) and those receiving blood (recipient) must be matched properly. This means, for example, that type-A blood donors should only give blood to recipients having type-A or type-AB blood, whereas type-B blood donors should only give blood to recipients with type-B or type-AB blood. Type-AB blood donors should only donate to type-AB recipients. Since you have type-O blood, you can donate blood to recipients with type-A, type-B, type-AB or type-O blood. Congratulations, you are a “universal donor.” On the other hand, people with type-O blood can only receive blood from type-O donors. People with type-AB blood can receive blood from type-A, type-B, type-AB or type-O blood donors and therefore, they are referred to as “universal recipients.”
January 22, 2003 _Goshen Independent
_____________________________________________________ {Simplified DNA molecule}
Samantha writes: Dear Doctor Bones,_________
Question: I saw a news story about DNA and cloning on TV, but they didn’t have much to say about it. Could you tell me about DNA and cloning?
Answer: Dear Samantha: DNA is the abbreviated name for “DeoxyriboNucleic Acid,” which is thought of by many scientists to be the world’s most interesting molecule. DNA is our body’s “genetic blueprint,” carrying the hereditary (genetic) information that is used to make proteins. A DNA molecule is a ladder-like connection of two strands of DNA that have been twisted into a spiral structure. Scientists refer to this as a “double helix.” The double-helical structure of DNA was first proposed by James Watson and Francis Crick in 1953. Watson and Crick won the Nobel Prize in Physiology or Medicine (1962) for their work with DNA. Rosalind Franklin, also played an important role in determining the structure of DNA. If you log onto http://ndbserver.rutgers.edu/ (the Nucleic Acid Database or NDB) you can view almost all of the known DNA structures. Speaking of nucleic acids, it was Johan Friedrich Miescher (1844-1895) who in 1869, isolated a substance he called "nuclein" from the nuclei of white blood cells. This substance came to be known as nucleic acid. Seventy-five years later (1944), Oswald Avery, Colin MacLeod, and Maclyn McCarty proved that our genetic code (as this pertains to our genes) was contained in the DNA molecule. A gene is a length of DNA (situated at some point on a chromosome) that holds the genetic code or “recipe” for making a particular protein. Chromosomes consist largely of DNA. Human beings each receive 23 chromosomes from their mother and 23 chromosomes from their biological father. Cloning DNA means making an exact duplicate (or cDNA) of some portion of DNA that is of interest to the scientist. It could also suggest copying a gene, for example. The copied gene can then be “amplified” into many copies. Cloning can also lead to the creation of cells or multi-cellular organisms by using the DNA from a single "parent" with the clone’s DNA being identical to that of the parent. One way of cloning an animal (for example, like Dolly the sheep) takes DNA from a donor cell and places it into the nucleus of an egg (ovum) whose DNA has been previously removed. In this instance, the complete genome is from the donor and the result will be a clone of the donor. Hello, Dolly.
____
February 5, 2003 _Goshen Independent
Jeff writes: Dear Doctor Bones,_________
Question: I like looking at the Moon. Can you tell me some interesting things about the Moon?
Answer: Dear Jeff: From the beginning of recorded history human beings have been fascinated with the Moon. And why not, the Moon (called “Luna” by the Romans) is the only natural satellite of the Earth and our next-door neighbor in the solar system. The mathematician, Thomas Harriot (1560-1621) is credited with constructing the first telescopic Moon map in the summer of 1609. Later that year, Galileo Galilei (1564-1642) began his telescopic examination of the Moon, compiling a number of drawings of the lunar surface. Mankind’s first visit to the lunar surface was in 1959, when the unmanned Russian spacecraft Luna 2 crash-landed on the Moon. In 1962, the unmanned U.S. Ranger 4 spacecraft crash-landed on the far side of the Moon. The far side of the Moon cannot be observed from Earth, because the Moon rotates once for every time it revolves around the Earth. The far side is sometimes referred to as the “dark side” of the Moon. It is proper to use the term “far side” rather than “dark side” because as the Moon orbits the Earth, all parts of the rotating Moon will eventually get illuminated by the Sun, even if we cannot see the Moon’s far side from Earth. It takes approximately 27 days and 8 hours for the Moon to complete one rotation about its axis. It equally takes 27 days and 8 hours for the Moon to make one orbit around the Earth and appear at the same position in space relative to the fixed positions of the stars on what astronomers call the “Celestial Sphere,” a tool they use to measure the observable night sky. The time required to make this orbit is known as the Moon’s “Sidereal Period.” This is different from the Moon’s “Synodic Period,” more commonly called the lunar month, which is approximately 29 days and 12 hours. On July 20, 1969 the headlines read, "That's one small step for man, one giant leap for mankind" when Apollo 11 astronaut Neil Armstrong became the first man to set foot on the Moon. Armstrong’s Apollo 11 colleague, Edwin "Buzz" Aldrin, followed him down the ladder of the Lunar Module "Eagle" to the lunar surface, while the final member of the Apollo 11 crew, astronaut Michael Collins, circled the Moon in the Command Module "Columbia.” The Moon’s gravity is about 1/6 of that on Earth. Therefore, if you weighed 180 pounds on Earth, you would weigh about 30 pounds on the Moon. Try logging onto http://home.hiwaay.net/~krcool/Astro/ww/ to calculate your weight on the moon and the planets. You can get complete Sun and Moon Data for One Day from the U.S. Naval Observatory at http://aa.usno.navy.mil/data/docs/RS_OneDay.html. I wish you Happy Travels.
February 19, 2003 _Goshen Independent
Gina writes: Hello Doctor Bones,___________________
Question: I'm sad about what happened to the astronauts on the space shuttle Columbia. Can you tell me some of the history of the space shuttle program?
Answer: Dear Gina: I'm also sad about the tragic loss of our brave astronauts. The Shuttle program started unofficially as far back as 1969. It was then that NASA engineers started thinking about ways to build a reusable spacecraft that could be launched like a rocket into outer space and then fly back to Earth like an airplane. In reality, the space shuttle behaves more like a glider than an airplane as it "glides" back to Earth. The first shuttlecraft was originally called Orbiter 101, but soon after it was renamed Enterprise to the satisfaction of Star Trek fans. At a weight of 150,000 pounds, Enterprise was the World's heaviest glider. Enterprise was never launched into space, but it did serve as a test craft for a series of shuttle approaches and landings. Enterprise's first free flight was on August 12, 1977. A Boeing 747 (that NASA bought from American Airlines) carried it "piggyback" to 22,000 feet whereupon it separated from the 747 and glided safely to Earth, landing along the 7-mile runway at Rogers Dry Lake, CA. NASA originally wanted to make five different orbiters, but they settled on four space shuttle orbiters: Columbia, Discovery, Atlantis and Challenger. The space shuttle Endeavor was built to replace the ill-fated Challenger, destroyed less than two minutes after launch on January 28, 1986. Columbia (Orbiter 102) was the first of the space shuttle orbiters to reach outer space. On April 12, 1981, Commander John Young and Pilot Robert Crippen, took Columbia into orbit around the Earth. At launch, Columbia, which consisted of two solid rocket boosters, an external fuel tank and the orbiter itself, weighed in at approximately 4.5 million pounds. Upon release of the rocket boosters and fuel tank (used to thrust Columbia off the Kennedy Space Center launch pad) Columbia weighed about 214,000 pounds. Two days later, Columbia landed safely at Edwards Air Force Base in California. In its history (1981-2003) Columbia made 28 flights. Each orbiter was designed to make 100 flights. It is troubling that Columbia was lost after having satisfied only a quarter of its potential for space investigation. We can all hope that what is learned from this tragedy will help NASA scientists and engineers make space travel significantly safer for future space shuttle astronauts.
March 5, 2003 _Goshen Independent
Abby writes: Dear Doctor Bones,_____________
Question: What can you tell me about vitamins?
Answer: Hello Abby: Vitamins are "vitally" important to life. In fact, "vitamin" comes from the word "vitamine," which was coined by the biochemist Casimir Funk as far back as 1912, and is a contraction of the words "vital" and "amine." However, since not all vitamins are amines (containing nitrogen) vitamine was shortened to vitamin. By definition, vitamins are a group of organic compounds that in small doses are essential for metabolism (energy for cells) of the food we eat, and the growth and maintenance of our body. We require a number of vitamins (as supplied by our diet) to help make the many enzymes and hormones that we need to live. Vitamins are of two distinct types: Water-Soluble (meaning to dissolve in water) and Fat-Soluble (meaning to dissolve in fat). The water-soluble vitamins that we need are Vitamin C and an assortment of B-vitamins, whereas the fat-soluble vitamins we require include those of Vitamins A, D, E and K. Vitamin A was the first vitamin to be discovered. In 1913, the biochemist Elmer V. McCollum and his colleagues conducted nutritional studies that led to the discovery of vitamin A in butterfat and cod liver oil. McCollum originally called it "fat-soluble factor A" and then later "vitamine A." We store vitamin A in our liver. The earliest symptom of a vitamin A deficiency is night blindness. Perhaps you've heard someone say, "Eat your carrots for good eyesight!" Well, in truth, carrots contain a chemical substance called "beta-carotene" (carotene, coming from carrots) which the body can convert to vitamin A when needed. Vitamin D is a fat-soluble vitamin that exists in several forms. The form we humans need is vitamin D3, or "cholecalciferol." Among the many useful functions of vitamin E is that it acts as an antioxidant in the body, scavenging free radical compounds. The "K" in vitamin K refers to the German word "koagulation." Coagulation as we know it refers to blood clotting. Vitamin K is essential for the functioning of several proteins involved in blood clotting. Water-soluble vitamin C (also called ascorbic acid) serves many useful functions in the body, perhaps the most important of which is in the maintenance of the connective tissue that holds your cells together. We require a family of water-soluble B-vitamins, which includes those of Thiamin (vitamin B1), Riboflavin (vitamin B2), Niacin (vitamin B3), Pantothenic Acid (vitamin B5), Pyridoxine (vitamin B6), Biotin (vitamin B7), Folic Acid (vitamin B9) and Cobalamin (vitamin B12). Although the various B's have many important jobs to do, the most common of which is in the conversion of food to energy (metabolism). Eat wisely and enjoy your life!
March 19, 2003 _Goshen Independent Tom writes: Dear Doctor Bones,___________________
Question: Why are nuclear weapons so dangerous?
Answer: Hi Tom: Nuclear weapons harness the power of the atomic nucleus. They are the most destructive explosive devices ever developed and are extremely dangerous for a number of reasons. Today's nuclear weapons have many times the destructive power of the first nuclear weapons, which were used at a heavy price (killing nearly 145,000 people in Hiroshima, Japan and some 70,000 people in Nagasaki, Japan) to bring an end to World War II. Presently, there are at least eight countries possessing nuclear weapons: the United States, Russia, Great Britain, France, China, India, Pakistan and Israel. The United States and Russia have the majority of these weapons, in the neighborhood of 24,000 such devices. In the hands of evil, nuclear weapons become a serious threat to all. Exploding a nuclear bomb over a city will cause extensive destruction. The immediate effects of the explosion include that of an intense heat wave, a shock wave and prompt ionizing radiation and nuclear particles. Objects near the center (also called the hypocenter) of the blast will be vaporized by the intense heat generated. The explosion also sends out a shock wave, which acts like an expanding soap bubble, knocking down everything in its path. The release of neutrons, beta particles (fast moving electrons), alpha particles (energetic helium nuclei) and gamma rays (X-rays) from a nuclear blast can destroy our cells and threaten our lives. Neutrons and gamma rays easily penetrate our body causing serious damage. Gamma rays can ionize molecules in human cells, making these molecules highly reactive and potentially damaging to the normal chemical processes used by cells. The result may be the immediate or delayed stoppage of a cell's metabolism and replication. Cells that undergo rapid division (like hair follicle cells, for example) are the most sensitive to radiation injury. This is why hair loss is the most famous symptom of radiation poisoning. The delayed effects from a nuclear explosion include that of the radioactive fallout (dust) and other environmental hazards. Depending upon the type of radioactive material released by the blast, these effects could last from hours to centuries. The winds can spread the radioactive fallout many miles from the hypocenter of the explosion, endangering the lives of millions of people.
April 2, 2003 _Goshen Independent Paul writes: Hey Doctor Bones,__________
Question: I am very interested in the war in Iraq. What can you tell me about smart bombs?
Answer: Dear Paul: Before we examine how a "smart" bomb works, it would be useful to take a look at a conventional dumb bomb. A dumb bomb is called "dumb" because after it is dropped from an airplane (i.e., "bomber") it has no means to steer itself as it falls to the ground. The bomb itself, is simply a bomb casing that contains an explosive material, a trigger and a fuze. The trigger, which may go off either on impact or after some time-delay, triggers the "fuze" (as it's called) that ignites the bomb's explosive material. In this way, the bomb can be made to explode on impact or near the target. Because the dumb bomb cannot steer itself to the target, the bomber may need to drop several dumb bombs in order to destroy the target. A smart bomb is "smart" because it has a means for controlling its flight to the intended target. The garden-variety smart bomb has an electronic sensor, an onboard computer and a battery that powers everything. Unlike a dumb bomb, a smart bomb has adjustable flight fins (whose movement is computer controlled) to create lift and help steer the bomb as it falls under gravity to the target. In this respect, a smart bomb performs essentially like a heavy glider. Smart bombs are typically TV/IR-guided, Laser-guided or GPS-guided. A TV/IR-guided bomb has either a TV video camera or an infrared (IR) camera (used for night vision) as its electronic (in this case, visual) sensor of the target. A TV/IR bomb can be directed to its designated target, either remotely or automatically. With remote operation, for example, the bomb behaves like a remote control plane. The bomb can be steered to the target by the bombardier viewing the video images from the bomb's TV/IR video camera. Laser-guided smart bombs have a laser-seeking device as their electronic sensor rather than a video camera. The target is illuminated with laser light from either someone on the ground (like from a tank) or from the air (as from an airplane) and the laser-seeking device in the smart bomb sees the reflected laser light and can zero in on the ground target. GPS-guided smart bombs use Global Positioning System or "GPS" technology to guide the bomb to its target. The GPS-guided bomb has a control computer, an inertial guidance system and a GPS receiver. The GPS receiver interprets signals from GPS satellites, which orbit the Earth, to track the bomb's position in the air. Ideally, the GPS-guided bomb can hit within a few feet of its target.
April 16, 2003 _Goshen Independent Kevin writes: Dear Doctor Bones,______
Question: I saw Paul's question about smart bombs. I want to know about cruise missiles. What can you tell me?
Answer: Hi Kevin: A cruise missile has wings and an engine and behaves basically like a small airplane using aerodynamic lift for most of its flight path. The primary job of a cruise missile is to deliver a 1000-pound bomb to a battlefield target. Some cruise missiles are designed to drop submunitions, which are warheads that contain bomblets. When released, bomblets can spray their principle agent over the intended target. The typical cruise missile (designed to fly at low altitudes to elude radar and infrared detection) has a missile body, propulsion system (low-thrust engine), guidance and navigation systems and a weapon (bomb or bomblets). They can be launched from ships, submarines or aircraft. There are at least 12 countries that have cruise missiles, including the United States, Russia, Great Britain, China, Germany, France, Italy, Israel, Japan, Taiwan, Norway and Sweden. Cruise missiles that are presently available to deliver weapons of mass destruction WMD (nuclear, chemical, and biological agents) include the U.S. Tomahawk and Advanced Cruise Missile (ACM), the Russian SSN-21 and AS-15, and the French Apache. The U.S. Tomahawk is by far the most famous cruise missile name, having been used in Operation Desert Storm (1991) and again in Operation Iraqi Freedom (2003). The Tomahawk, which costs about $1.5 million per missile, is a little more than 20 feet in length at launch and weighs 3500 pounds (including a 550-pound solid rocket booster). The Tomahawk has a diameter of 21 inches, a wingspan of nearly 9 feet and a turbo-fan engine that produces 600 pounds of thrust. The missile has a cruising speed of 550 mph (880 km/h) and can fly upwards of 870 nautical miles (1000 statute miles, 1609 km). Cruise missiles are known most notably for their accuracy in hitting their targets. Four different systems exist to help guide a cruise missile to its intended target, including IGS (Inertial Guidance System), Tercom (Terrain Contour Matching), GPS (Global Positioning System) and DSMAC (Digital Scene Matching Area Correlation). The Tomahawk Block II model, uses IGS aided by Tercom and DSMAC. The Tomahawk Block III model, adds GPS guidance to the Block II guidance system. In 2004, the even more sophisticated Tactical Tomahawk is projected to enter the U.S. arsenal.
April 30, 2003 _Goshen Independent
Diane writes: Dear Doctor Bones,
Question: I found out that there are a lot of applications for lasers. What do you know about lasers?
__
Answer: Dear Diane: Yes indeed, there are many useful applications for lasers. Perhaps the most familiar to us is the barcode scanner at the supermarket, which uses a diode laser. Diode lasers are also used in another familiar item to us, the CD player. There are a number of different types of lasers, including for example, gas-lasers, excimer, solid-state, diode, dye, free-electron and quantum cascade lasers. The first laser (also known as the first "optical maser") was the solid-state ruby laser invented by Theodore Maiman in 1960. However, there is still some controversy that Gordon Gould was the first to build a working optical laser. It was Gould who coined the word "LASER," which is an acronym for Light Amplification by the Stimulated Emission of Radiation. Gould was also awarded patents for his early work in lasers. The concept of stimulated emission, which was fundamental to the development of the laser, was first formulated by the physicist Albert Einstein in 1917. Stimulated emission was first associated with the "MASER," which is an acronym for Microwave Amplification by Stimulated Emission of Radiation. Charles Townes and Arthur Schawlow invented the maser in 1954, using microwave radiation (high frequency radio waves) and ammonia gas as the maser medium in order to create, amplify, and transmit an intense, highly focused beam of high frequency radio waves. A laser is essentially a maser that ends in visible or ultraviolet light rays or "photons" (photons are bundles or "quanta" of electromagnetic radiation) of the same wavelength, which is the result of the stimulated emission process. Because the resulting laser photons have the same wavelength, laser light is called "monochromatic" light, meaning "of one color." This is one of the reasons that lasers are very different from ordinary light, like that from a light bulb, which contains many wavelengths. Another reason laser light is different from ordinary light is that laser light is "coherent" or "organized" light. This simple means that the wavefronts of the individual photons making up the laser light are in "phase" or in "synchronization" with each other. Laser light, is in fact, a train of coherent photons. Ordinary light is called "incoherent" or disorganized" light because individual photons do not enjoy the same phase relationship. Laser light is also uni-directional (moving in one direction) and of high irradiance (brightness) unlike light from a light bulb, which travels in all directions and is considerably less radiant.
May 14, 2003 _Goshen Independent Sharon writes: Dear Doctor Bones,___________
Question: Why is it so tough to get ketchup out of the bottle?
Answer: Dear Sharon: Americans love their ketchup, but they don't particularly like all of the shake, rattle and roll that it sometimes takes in order to get the "red stuff" out of the bottle. Over the years, a number of tricks have been devised to get ketchup out of the bottle and onto the multitude of foods we enjoy it on. [One girl I know likes it on bananas. Yuck!] Some of these tricks, which are all effective to some degree, include sticking a knife into the bottle (an old favorite), shaking vigorously before opening the cap, warming the bottle in hot water and many more. The trouble with ketchup is that after sitting around in the bottle it becomes like thick pudding, which of course, if the bottle is made of glass makes for quite a challenge in getting it out of the bottle. If the bottle is of the plastic "squeeze" variety (something we didn't have when I was a kid), then we could simply squeeze it out of the bottle, with a little shaking if necessary. Some vigorous shaking (even with the advantage of the plastic squeeze bottle) before we pour will make for easier flowing ketchup. The reason behind the shaking is that ketchup is a thixotropic (pronounced "thick-so-tropic") substance. Thixotropic ("thixo" is Greek for "touch") substances exhibit both solid-like and liquid-like behavior depending upon the forces (like shaking, for example) that are applied to them. When sitting for long periods in the bottle, ketchup is more solid-like than liquid-like because of the long-chain molecules in ketchup that coil together, sort of like a pile of spaghetti. However, when we shake it vigorously, the long-chain molecules start to uncoil from each other and ketchup becomes more liquid-like and hence flows more easily out of the bottle. [Paint is a thixotropic substance that is quite familiar to us. Quicksand is yet another example. When you move around in quicksand, it becomes less solid-like and more liquid-like, which is why you can drown in quicksand.] Once the ketchup reaches the food we've poured it on, like French fries, for example, it starts to revert back to its solid-like state. This is good because we surely don't want to have fluid-like (watery) ketchup on our fries. Did you know that Americans spend close to $500 million a year on ketchup? This seems reasonable since ketchup is America's favorite condiment. Did you know that ketchup is also known as catsup, catchup and catsoup, among other names? Kids between the ages of 8 and 15 account for more than 50% of all the ketchup consumed.
May 28, 2003 _Goshen Independent
Tamara writes: Dear Doctor Bones,_________
Question: Is Albert Einstein the World's most famous scientist?
Answer: Dear Tamara: Albert Einstein (1879-1955) is certainly one of the most famous if not the most famous scientist the World has ever known. He is in the company of such famous scientists as Isaac Newton, Galileo Galilei, Madame Curie, Thomas Edison (scientist and inventor) and Ben Franklin (scientist and statesman) to name just a handful. Einstein was born on March 14, 1879 in Ulm, Germany and spent his school days in Munich, Germany. As a boy, Einstein was curious about nature. One story tells of Einstein's fascination with a magnetic compass and his wonder about the "invisible force" (magnetism) that always points the compass needle North. Even at an early age, he imagined that there were secrets to be unlocked behind this and other physical phenomena. In fact, it was Einstein who later said, "Imagination is more important than knowledge." Perhaps this is one of the reasons he disliked the schools of his era, where regimentation was the norm (focusing on memorization and obedience to authority) and free expression and imagination were frowned upon. Despite these early years, Einstein's imaginative powers continued to flourish and by 1905, the year that science historians now refer to as "the year of wonders," (from the Latin: annus mirabilis) Einstein would publish several landmark scientific papers. These papers would reveal for the first time, to the members of the science community, Einstein's interpretation of Brownian motion, his explanation of the Photoelectric Effect and his now famous Special Theory of Relativity. Of this phenomenal year in the history of Modern Physics Einstein would simply state: "A storm broke loose in my mind." One remarkable consequence of the special theory of relativity is that if a particle emits a certain amount of energy, then its mass must decrease proportionally in such a way that the famous equation E=mc² results. In this equation, E represents energy, m is the mass and c² is the speed of light squared, which is a very large number. By 1915, Einstein had completed his General Theory of Relativity, the equations from which astronomers calculate, for example, the distribution of matter in a galaxy. For his work in explaining the photoelectric effect, which details that light consists of photons (quantum particles of light energy), Einstein was awarded the Nobel Prize in Physics in 1921.
June 11, 2003 _Goshen Independent
Yana writes: Hello Doctor Bones,
Question: My uncle is a chemist. What do chemists do?
Answer: Dear Yana: You can be proud of your uncle the chemist as chemists play an important role in society. Chemistry is a natural science concerned with the systematic study of the composition as well as the physical and chemical properties of organic and inorganic substances (matter). A job for the garden-variety laboratory chemist might be in the Reaction, Isolation, Purification, and Identification (also known as "RIPI") of substances of interest in his or her laboratory. Chemists use well-defined methods to answer important questions such as: "What is this substance made of?" and "What are the physical and chemical properties of the substance?" From the data, the chemist will know if the compound is something already available or if it is a new discovery. Interesting things can happen in a chemical lab and finding new chemical compounds is one possibility. You never know when the next important discovery (i.e. aspirin, penicillin, lexan plastic and even aspartame or "NutraSweet") will be made. The four primary areas of chemistry are Analytical, Organic, Inorganic and Physical. In a very basic sense, analytical chemists are interested in identifying the elements (atoms) and compounds (molecules) that make up a particular substance, from which they attempt to determine both its composition and structure. An organic chemist is generally concerned with the synthesis (the formation of compounds from simpler compounds) of desirable organic (carbon containing) compounds for different applications. Inorganic chemists are mostly interested in evaluating compounds containing atoms other than that of carbon. Physical chemists use their scientific skills to investigate the physical properties of atomic and molecular structures. They are also curious about the rates (how fast or how slow) of chemical reactions and how they can use this information in an attempt to "control" chemical reactions. Biochemists are also chemists. Biochemistry is the marriage of biology and chemistry. Chemists are not confined to the lab. There are many "real world" opportunities for them to utilize the skills they have acquired as chemists. Chemists can be found in diverse industries, as teachers (high school, college and university), astronauts, as medical doctors, environmental scientists, and in local, state and federal government jobs to name just a few.
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July 9, 2003 _Goshen Independent
__________________________________ Depiction of SARS Virus
Connie writes: Dear Doctor Bones,____
Question: I've been hearing about Monkey Pox and the SARS virus. What are viruses?
Answer: Hi Connie: Before getting to Monkey Pox and SARS, let's define what a virus is. A virus is a minuscule invader of cells whose primary goal is to reproduce itself at the expense of the cell it has invaded. Although viruses carry along a blueprint (containing DNA or RNA) for replication, because viruses are acellular (not composed of cells) they must invade living cells in order to reproduce. You've probably already heard something about DNA, which stands for DeoxyriboNucleic Acid. In the case of viruses, DNA is the molecule that carries the genetic instructions (blueprint) used to make more virus. RNA stands for RiboNucleic Acid and like DNA, RNA can also store genetic information. The core of a virus, which contains the DNA or RNA, is protected from harm by a protein coating called a "capsid." At this point the virus is called a "naked" virus. Some viruses have yet another layer, one constructed of fat and protein that surrounds the capsid. These viruses are called "enveloped" viruses, but despite the extra layer, they are surprisingly less resistant to disinfectants, for example, than are naked viruses. Before entering a living cell, a virus must attach itself to the outside of the cell. Once attached, naked viruses can inject their entire capsid into the cell or just the genetic material contained within the capsid. An enveloped virus leaves its envelope outside of the cell. Once inside, viruses attempt to reprogram the cell's metabolic machinery, to produce more of the virus, and perform less of normal cellular activities. The newly formed viruses can either leave the cell by a process called "budding," whereby the new virus "buds" out from the cell a few viruses at a time or by the death of the cell, which is called "lysis." Monkeypox, like smallpox (which fortunately has been eradicated throughout the World) belongs to the orthopox virus genus. Monkey pox, can cause fever-type illnesses (similar to those of other pox-type viruses) in humans and animals. Until recently, monkey pox was confined to central Africa. Despite its name, monkey pox is more commonly spread to humans by infected squirrels or rats. The Centers for Disease Control (CDC) website (http://www.cdc.gov/ncidod/sars/basics.htm) will provide you with some useful information about SARS and what is being done to stop the spread of the disease. Take Care.
July 23, 2003 _Goshen Independent
Rick writes: Hi Doctor Bones,______
Question: I read your column about how airplanes fly. Can you tell me how helicopters fly?
Answer: Dear Rick: I would be happy to tell you how helicopters fly. Helicopters, like airplanes need lift to get off of the ground. However, unlike an airplane, which is a fixed-wing aircraft, a helicopter has a main rotor with blades that act as "moving wings." If the spinning helicopter blades are all tilted slightly (also called the pitch angle) in the upward direction, then the air pressure above the helicopter blades as they "bite" into the air, is lower than the air pressure below the blades, and "lift" is created. If the main rotor spins sufficiently fast, the helicopter can lift off and hover in the air. In order for the helicopter to climb higher, the pitch angle of the blades is increased. Decreasing the pitch angle of the blades allows the helicopter to descend. The "collective pitch" of the helicopter blades is controlled via the collective control lever, which is located at the pilot's side. The collective control lever, which simultaneously or "collectively" changes the pitch angle of the blades, is linked to the engine power so that if the pitch angle is increased or decreased, the revolutions per minute (RPM) of the main rotor can be kept constant. To move the helicopter forward, backward or sideways, the pilot uses an additional control called the cyclic control. Using the cyclic control stick, the pilot can change the angle of the main rotor blades individually as they spin. Moving the cyclic control stick forward tips the nose of the helicopter down and the helicopter moves forward and moving the cyclic control stick back will tip the nose up and the helicopter moves backward. Directing the cyclic control stick to the right banks the helicopter to the right and to the left banks the helicopter to the left. At the tail-end of the helicopter is a tail rotor, which serves a very useful function. Without a spinning tail rotor, as the main rotor blades spin in one direction the helicopter would spin unimpeded in the opposite direction. This is a consequence of Newton's Third Law of Motion and is known as a torque reaction. The tail rotor blades being much shorter than the main rotor blades must spin faster (three to six times faster) than the main rotor blades in order to stabilize the helicopter. The pilot uses the two tail rotor control pedals on the floor of the helicopter to control the pitch angle of the tail rotor blades. Happy to hear that you read my column.
August 6, 2003 _Goshen Independent
Erica writes: Dear Doctor Bones,______
Question: I've been studying the Solar System. Do you know some interesting facts about the Sun?
Answer: Dear Erica: Scientists estimate that the sun has been shining for around 4.5 billion years and should continue to shine for another 5 billion years or so. It was the Polish astronomer, Nicolaus Copernicus (1473-1543), who advanced the heliocentric (meaning "sun" at the center) theory of the solar system despite much criticism at the time in favor of Ptolemy's geocentric (meaning "earth" centered) theory of the solar system. [Helios was the Greek god of the sun. Sol was the Roman god of the sun from which we derive the word "solar."] Ptolemy, who is believed to have lived during the 2nd century A.D., was an Alexandrian astronomer, mathematician, and geographer who believed that the Earth was at the center of the universe. The Ptolemic view of the universe prevailed for more than 1000 years. The Copernican theory of the solar system would eventually be proven to be the correct one when Johannes Kepler (1571-1630), the German astronomer and mathematician, formulated his three laws of planetary motion using astronomical data carefully collected by the Danish astronomer Tycho Brahe (1546-1601). The earth is on average 93 million miles away from the sun, which means that it takes a little more than 8 minutes for sunlight to reach the earth. Our sun (also called a G2 star by astronomers) is considered to be a second or third generation star, which means that the sun not only burns hydrogen as fuel but also helium and elements heavier than helium. Helium, by the way, is the second heaviest element in the Periodic Table of Elements. It was discovered by Jules Janssen (1824-1907) a pioneer in the use of photography for solar spectrocopy during his examination of a total solar eclipse. The name "helium," which was coined by Sir J. Norman Lockyer (1836-1920) is derived from the word "Helios." The Sun is about 865,000 miles in diameter, which is around 108 times larger than the Earth's diameter of 8000 miles at the equator. The sun's volume is large enough to hold nearly 1.3 million Earths. Wow! Here's a sun joke for you: "What do you call an alien spacecraft that ventures too close to the Sun?" Answer: "An unidentified frying saucer." Ha. Ha.
August 20, 2003 _Goshen Independent George writes: Hey Doctor Bones,______ _______
Question: What's the ozone layer all about?
Answer: Dear George: The ozone layer contains ~ 90% of the atmospheric ozone and resides within a region of the earth's atmosphere called the stratosphere, which extends from about 12 to 50 kilometers above the surface of the earth. The ozone layer contains gaseous ozone molecules represented by the chemical formula O3, which shows us that an ozone molecule consists of three oxygen atoms. This is a molecule different from the oxygen molecule that we need for life whose chemical formula is O2. Ozone molecules have just the right shape and size to absorb certain radiation from the sun that can be potentially dangerous to earth dwellers like us. The ozone layer, in this case, acts as a protective shield blocking higher energy ultraviolet-C (UVC) radiation and partially blocking lower energy ultraviolet-B (UVB) radiation. The word ozone comes from the Greek word ozein, which means, "to smell." You may have smelled ozone after a lightning storm. Lightning is an electrical discharge in the atmosphere that can lead to the formation of ozone and its characteristic smell. Ozone molecules O3 are naturally formed and destroyed in the stratosphere in a series of chemical reactions involving oxygen molecules O2, oxygen atoms O, and sunlight. For example, in the formation of ozone, sunlight with the appropriate energy splits O2 into two O atoms. We can represent this as the chemical reaction, O2 + sunlight → O + O. [O atoms can also be formed from the reaction, O3 + sunlight → O + O2.] In another reaction, O atoms combine with oxygen molecules to form ozone, O + O2 → O3. Ozone can also be destroyed by the reaction, O + O3 → O2 + O2. These reactions, known as the "Chapman Reactions," after the scientist who discovered them, illustrate the balance between the natural formation and destruction of ozone in the stratosphere. During the 1970's scientists learned that man-made compounds called chloro-fluoro carbons or CFC's led to the greater destruction of ozone in a complex series of chemical reactions, disturbing the natural balance. One continuing consequence of the disruption in the natural ozone balance has been the formation of an "ozone hole" in the ozone layer over Antarctica. Fortunately, scientists and other concerned citizens witnessed the first global agreement to restrict CFC's with the signing of the Montreal Protocol in 1987.
_____ __The Chapman Reactions of Ozone
September 3, 2003 _Goshen Independent
Stephanie writes: Dear Doctor Bones,_______ ___The Red Planet
Question: Did you know that Mars is closer to Earth than it has been in 60,000 years?
Answer: Dear Stephanie: Yes, I heard that and thanks for reminding me, since I wanted to put together some interesting facts about Mars for you and the other readers of the Doctor Bones column. On August 27, 2003 the Earth was as close as 55,758,000 kilometers (34,646,400 miles) to Mars. It won't be until August 28, 2287 that the Earth and Mars will be nearly this close again. I wonder what the Earth will be like in 284 years from now? Mars (also called the Red Planet) is the fourth planet from the Sun (Earth being the third planet). Mars has been observed by many cultures dating as far back as 400 BC and the Babylonians who called Mars, Nergal - God of the midsummer Sun. The ancient Egyptians called Mars, Har décher - The Red One and the Greeks called Mars, Ares, after their God of War. We take the name Mars from the Romans who named the planet after their God of War. Mars orbits the Sun at an average distance of about 142 million miles. It takes Mars nearly twice as long (23 months) to orbit the Sun than does the Earth (12 months). The diameter of Mars is about half that of the Earth, around 4220 miles. The length of the Martian day (24 hours and 37 minutes) is very similar to that for we Earthlings. As far as the atmosphere on Mars is concerned it is cold, dry, and almost all carbon dioxide gas (~ 95%). Unlike the Earth's atmosphere, which is high in nitrogen gas (79%) and oxygen gas (20%), the Martian atmosphere has very little nitrogen (3%) and oxygen (0.1%). The surface temperature of Mars ranges from a balmy high of 68 °F (20 °C) to a very bitter low of -220 °F (-140 °C). There are two small moons orbiting Mars, one is called Phobos (meaning fear) and the other is called Deimos (meaning terror). Phobos and Deimos were discovered by the American astronomer Asaph Hall in 1877 while using the U. S. Naval Observatory's 26-inch refracting telescope called the "Great Equatorial," which was then the largest telescope of its kind in the world. Hall was born on October 15, 1829 in Goshen, Connecticut. Phobos is the larger of the two Martian moons and it revolves around Mars at the rate of three times per day. Wow! Deimos, on the other hand, takes about 1.25 days to orbit Mars. Some astronomers believe that Phobos and Deimos are in fact, captured asteroids. Happy Mars watching.
September 17, 2003 _Goshen Independent
Jerry writes: Hi Doctor Bones,_______
Question: What is the difference between sound waves and light waves?
Answer: Dear Jerry: There are actually several important differences between sound and light waves. One difference is in the velocities of the respective waves. Sound waves, for example, at room temperature move through the air at a speed of approximately 1,100 feet per second. The speed of sound is dependent on the air temperature. The cooler the air, the slower the speed of sound, the warmer the air, the faster the speed of sound. Light waves, on the other hand, travel through empty space at a speed of approximately 186,000 miles per second, and at nearly the same speed in air, independent of the temperature of the air. In fact, the second major difference between sound waves and light waves is that light waves travel through empty space (also called a vacuum), whereas sound waves cannot travel through empty space. You could prove to yourself that sound does not travel through a vacuum by using a simple experiment that features a ringing bell in a jar. When the jar is filled with air we can hear the sound of the bell, but when we evacuate the air from the jar we no longer hear the bell ringing because we have eliminated the medium through which the sound travels. In this case, we have proven that sound waves require a medium for travel, the medium simply being the material through which sound travels. The denser the medium, the faster the speed of sound. Sound waves can travel through all materials, but light waves cannot travel through all materials. Sound is constructed of what are called longitudinal waves. These are alternating compressions and expansions (or rarefactions as they are called) of the material that the sound wave happens to be traveling through. You can imagine this type of wave behavior as you might imagine a slinky contracting and then expanding as it moves along. In a longitudinal wave, particles within the medium oscillate back and forth in a direction parallel to the movement of the sound wave. Light is composed of transverse waves in an electromagnetic field. An electromagnetic field has both electric and magnetic field components, hence the name "electromagnetic." In a transverse wave, particles move in a direction perpendicular to the direction of the moving wave, oscillating up and down as the wave passes through. When most of us refer to "light," we are concerned with visible light. Visible light, is in fact, only a very small part of what scientists call the "electromagnetic spectrum," which includes all types of electromagnetic radiation, from low-energy radio waves to high-energy gamma rays. I'll wave good bye now.
October 15, 2003 _Goshen Independent
Carlota writes: Dear Doctor Bones,_______________
Question: How does a telescope work?
Answer: Dear Carlota: Telescopes have been around since the early 1600's when astronomers like Galileo Galilei (1564-1642) and Johannes Kepler (1571-1630) used the first telescopes to study the heavens. Science historians believe that the Dutch eyeglass maker Hans Lippershey (1570-1619) was the father of the telescope. Telescopes, which are defined as optical instruments used to view distant objects, have three main functions: (1) to collect light in order to brighten the image, (2) to resolve the image and (3) to magnify the image. The most common type of telescope is that of the Galilean-type: a variable length tube, with an inner tube that slides freely within an outer tube. At one end of the telescope is the eyepiece (generally with a plano-concave lens) which acts as a magnifying glass, while at the opposite end we have the objective lens, which is used to gather light from distant objects that we hope to see more clearly. This is also called a refracting telescope. The objective lens, which collects the light rays, has a surface that is curved outward (convex) so that it can bend (refract) or "focus" the light into a tiny bright point also called the focal point. The focal length for a refracting telescope is the distance between the objective lens and the focal point. The longer the focal length the more powerful the telescope. The objective lens produces an upside-down image of the object at the focal point. The upside-down image is inverted (turned right side up) by the lens in the eyepiece, which also creates the magnified image that we see. Telescopes have a telescopic power or magnification rating. The magnifying power is equal to the focal length of the telescope divided by the focal length of the eyepiece. For example, a telescope with a focal length of 1000 millimeters along with an eyepiece having a focal length of 20 millimeters has a magnification rating of 1000 mm / 20 mm = 50. This means that the image we see is 50 times larger than it appears to the naked eye. Another important type of telescope is a reflector telescope. Instead of using a lens to collect light rays, Isaac Newton, who developed the reflecting telescope in the late 1600's, used a curved metallic mirror to collect light rays. Reflector telescopes use a large concave mirror to collect light and focus it back to a diagonal mirror, which then directs the light to the eyepiece where it is magnified. Have a nice week.
May 12, 2004 _Goshen Independent Penny writes: Dear Doctor Bones,_______________
Question: I would like to know more about muscles. What do you know about muscles?
Answer: Dear Penny: There are as many as 639 named muscles in the human body. The three basic types of muscle are smooth muscle, cardiac (heart) muscle and striated (skeletal) muscle. Smooth muscle is located throughout the body in hollow organs such as the gastrointestinal system (esophagus, stomach, intestines), blood vessels (arteries and veins), urinary tract and the uterus. Smooth muscle is also called involuntary muscle because its contraction is controlled by the autonomic nervous system rather than by our conscious thoughts. Smooth muscle is called smooth because it has no striations or "stripes" like cardiac and striated muscle. Cardiac muscle is found only in the wall of the heart. Like skeletal muscle (as viewed under a microscope), cardiac muscle has a stripe-like pattern of fibers or striations. However, it behaves like smooth muscle, in that its muscular contractions are under involuntary control. This is a good thing. Can you imagine having to consciously keep your heart beating? Not a good idea! Striated or "skeletal" muscle as the name implies is attached to the skeleton. Skeletal muscle contractions are controlled by the somatic nervous system, which means that they are under voluntary control. The exception would be a skeletal muscle reflex action, which is under involuntary control. An example of this type of behavior would be when your doctor hits you just below the knee (along your patellar tendon) with a small rubber mallet and your lower leg naturally pops up due to the "knee jerk" reflex. If you go to a weight room or gym, I'm sure you will hear the bodybuilders talking about their various skeletal muscles: biceps, triceps, deltoids (shoulders) or "delts" as they call them, pecs, lats, traps, abs, calves and so on, to use their lingo. Muscles work in pairs. To give you an example, let's examine the interaction of the biceps, which is the muscle in front of the upper arm and the triceps, which is the muscle in back of our upper arm. When the biceps contracts, it pulls the lower arm upward, while at the same time the triceps stretches. As the triceps contracts, it extends the lower arm, while simultaneously the biceps stretches. The biceps and triceps muscles are said to be an antagonistic pair. In other words, they counteract each other as they perform their individual duties. Bye-bye.
July 21, 2004 _Goshen IndependentMary Beth writes: Dear Doctor Bones,_______
Question: The movie "The Day After Tomorrow" warns us of the impending doom because of global warming. Could this really happen? What is Global Warming?
Answer: Dear Mary Beth: The makers of "The Day After Tomorrow," a movie based on the theory of “abrupt global climate change,” say that the movie is intended to raise consciousness on the issue of global warming. The moviemakers admit to using their artistic license with the science for the sake of entertainment. The movie, which includes bowling ball sized hail hitting Tokyo, temperatures jumping from hot to very cold within hours (the next Ice Age) in North America, tornadoes striking Los Angeles and yes, there's more, is a bit far-fetched for the tastes of most scientists. The Day After Tomorrow appears to be a science fiction thriller that has too little science and too much fiction. Marshall Shepherd, a meteorologist at NASA's Goddard Space Flight Center in Greenbelt, Maryland says, "I'm heartened that there's a movie addressing real climate issues, but as for the science of the movie, I'd give it a D minus or an F." The theory of abrupt climate change suggests that if certain temperatures are reached, there may be both abrupt and large changes in climate, although not necessarily those depicted in the movie. Most scientists studying global warming tend to agree that changes in global climate will be more gradual than abrupt, |
