1. How Do X-Rays Work By: Carrie Lisle

2. 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

3. 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

4. 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

5. What is an X-ray? Eyes aren’t sensitive to higher energy level and shorter wavelengths of x-rays Both produced by movement of electrons in atoms Similar to visible light rays Both are wavelike forms of electromagnetic energy carried photons Have different energy levels

6. 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

7. 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

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9. The X-ray Machine Machine passes current through filament, heating it up Heat sputters electrons off filament surface Anode draws electrons across tube

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. Bibliography Dugdale, David. “How X-rays Work.” February 2004. 29 April 2004. Jacikas, Kelly and Mark Woodland. “X-Rays.” 16 October 2002. 29 April 2004. Juhl, Katie. “How do X-rays Work.” 26 April 2004. Moncton, David E. “X-Rays.” World Book. 2003 ed.

18. 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.