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How Do X-Rays Work. By: Carrie Lisle. Discovery of the X-ray. Original inventor- A. W. Goodspeed on February 22, 1890 Had no information or proof, didn’t take credit November 8, 1895, discovered by Wilhelm Conrad Roentgen. Discovery of the X-ray. Discovered by accident
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How Do X-Rays Work By: Carrie Lisle
Discovery of the X-ray • Original inventor- A. W. Goodspeed on February 22, 1890 • Had no information or proof, didn’t take credit • November 8, 1895, discovered by Wilhelm Conrad Roentgen
Discovery of the X-ray • Discovered by accident • Wilhelm was experimenting with electron beams in a glass discharge tube • Fluorescent screen in lab glowed when electric beam was turned on • Tube was surrounded by heavy black cardboard which should have blocked radiation
Discovery of the X-ray • Tried putting various objects between tube and screen • Put hand in front of tube, saw silhouette of bones • Called “X” rays because it was an unknown type of radiation • Name stuck despite friends’ suggestion for “Roentgen” rays
What is an X-ray? • Similar to visible light rays • Both are wavelike forms of electromagnetic energy carried photons • Have different energy levels • Eyes aren’t sensitive to higher energy level and shorter wavelengths of x-rays • Both produced by movement of electrons in atoms
What is an X-ray? • Electrons occupy different orbitals • Electrons dropping to another orbital releases energy in the form of electrons in atoms • Photon energy level depends on how far the electron is dropped • Photon-atom collisions may cause atoms to absorb energy • Photons’ energy level must match the difference between the orbitals
What is an X-ray? • Atoms making up body tissue absorb visible light photons very well • X-rays have too much energy, and therefore pass through most things • Soft body tissue doesn’t absorb X-ray photons well • Calcium atoms in bones absorb X-ray photons well
The Light Spectrum GAMMARAYS MICROWAVES XRAYS ^^^ ULTRA VISIBLE INFRARED RADIO VIOLET LIGHT WAVES
The X-ray Machine • Machine passes current through filament, heating it up • Heat sputters electrons off filament surface • Anode draws electrons across tube
The X-ray Machine • Electrons fly through tube with high force • Electron and tungsten atom collide • Knocks one of atoms electrons loose • Another electron takes empty place • Releases extra energy in photon form- high energy
The X-ray Machine • Atom’s nucleus can attract a speeding electron enough to change it’s course • Approaching nucleus, electron slows down and changes direction as it passes the atom • Slowing down causes electron to emit excess energy in X-ray photon form
The X-ray Machine • High-impact collisions generate a lot of heat • Rotating motor keeps anode from melting • Entire mechanism is surrounded by a thick lead shield • Shield keeps X-rays from escaping in all directions
The X-ray Machine • A small window in the shield lets out the photons in a narrow beam • Beam passes through filters on way to patient • Camera on opposite side of patient records X-ray pattern • X-ray cameras see chemical reactions, not visible light
The Harm of X-rays • X-rays hit an atom, knocking off electrons to create an ion • Ions cause unnatural chemical reactions inside cells • Charge can break DNA chains • Cells with broken strands of DNA will die or develop a mutation • Can cause various diseases or even cancer
X-ray Radiation • Only large amounts of X-rays cause radiation • Can reduce cell division and damage genetic material • X-ray machine users use protection • Lead shields and vests
What are X-rays used for? • Used in radiation treatment • To look at bones • To see possibly swallowed things in the body • To see gunshot wounds • To look at gallstones • To examine teeth • In crystal research
Bibliography • Dugdale, David. “How X-rays Work.” February 2004. 29 April 2004. <http://www.keele.ac.uk/depts/ uso/hs/rad/xrays.html> • Jacikas, Kelly and Mark Woodland. “X-Rays.” 16 October 2002. 29 April 2004.<http://www.sanjuan. edu/schools/arcade/XrayWJ.html> • Juhl, Katie. “How do X-rays Work.” 26 April 2004. <http://www.cord.edu/faculty/manning/ physics215/studentpages/katiejuhl.html> • Moncton, David E. “X-Rays.” World Book. 2003 ed.
About the Author Hi! My name is Carrie Lisle. I chose to do x-rays for my project because I’ve always wondered how doctors could see to your bones and security at the airport could see what was in people’s bags.