|MadSci Network: Biochemistry|
Well Casey, I hate to disagree with your Mom, but since you did ask I will reply. The human body as a whole has practically no magnetic properties. And even if your hand was acting as a magnet, it wouldn't produce the type of motion that you are describing. Try this experiment. Take your threaded needle and hold it over a real magnet. If the magnet is strong enough for the needle to feel its pull, it should be pulled towards it uniformly and not sway. Any swaying or movement of the needle is due to the unsteadiness of the hand holding it, and currents in the air. If you hold your hand out flat in front of you, not resting it on anything, you'll notice that it is never truly still. It is always moving a little. A psychologist might also tell you that if you want the needle to sway one way or the other, you might subconsciously cause it to, but I'm not a psychologist. All I can tell you is that it is not due to any magnetic properties of the human body. Another experiment to try is to hang the needle from something steady. It still moves a little, because their are small currents in the air around it. Try blowing gently on it from a distance. Notice how easy it is to make it move. Also try putting your hand under it, while it is hanging from something. If you are very careful to be still and not breathe on it, you will notice that the swaying of the needle remains unchanged by the presence of your hand. It was swinging before, and it continues to sway more or less randomly due to air currents. Then hang the needle down inside of a jar or something that shields it from air currents. You will have to cover the mouth of the jar. I taped the thread to a ruler, then laid the ruler over the open mouth of a glass bottle, with the needle hanging down into it. If the jar was on a sturdy surface, the needle eventually stopped swaying to any amount that I could see. Having said all of this however, some of the individual atoms in the human body do have magnetic properties. Normally they are all randomly oriented so that there is no overall magnetic field associated with them, but their magnetic properties can be used by scientists and doctors to "see" inside the body using a technique called Magnetic Resonance Imaging, or MRI. In MRI, a very powerful external magnetic field is used to cause all of the magnetic atoms in a region of the body to rotate so as to align their magnetic fields with an applied external field. Then radio waves are beamed at the part of the body you want to look at. Some of these are absorbed by the magnetic atoms (mostly hydrogen atoms in water molecules) in that region, causing them to flip their magnetic field. Later, these atoms flip back to their original orientation, and give off more radio waves. These radio waves can be detected by sensitive instruments and used to "see" inside of the body. Here is a website describing MRI: http://www.cis.rit.edu/htbooks/mri/ You can also find other websites on it by searching for MRI or Magnetic Resonance Imaging using Yahoo or some other search engine on the Internet. Using MRI, doctors can look inside of the body for tumors and other things, and scientists can conduct research on changes that go on in the brain during thinking, and in muscles when they are contracting. They could also probably look and tell what sex a baby in the mother's womb is, but usually use a technique called ultrasound is used to do this, which uses sound to see inside the body. So you see, you can use magnetic properties to tell what's going on inside your body, it just takes a little more expensive equipment than a needle and thread. And although MRI can't tell you what sex your kids will be in 10 or 20 years, it can tell you a lot. I hope you find it as exciting as needle and thread fortune telling. I know I do. Thanks for the question. Sincerely, Todd Holland Mad Scientist and Graduate Student in Biophysics at the University of Illinois at Urbana-Champaign
Try the links in the MadSci Library for more information on Biochemistry.