X-Rays

By: Courtney ThomasSara KielbasaKelsey TamburriLauren Goldfinger

Brief Background

X-rays were first discovered accidentally by Wilhelm Conrad Röntgen in 1895.

X-rays are waves of electromagnetic energy that have a shorter wavelength than normal light

He discovered that these new invisible rays could pass through most objects that casted shadows including human tissue but not human bones and metals.

Within a year of the discovery many scientists replicated the experiment Röntgen performed and began using it in clinical settings

In 1901 Röntgen won the first Nobel Prize in Physics

How They Were Discovered Röntgen discovered the

new ray while working with a cathode tube in his laboratory.

The tube was a glass bulb that had positive and negative electrodes inside. When the air was removed from the tube, and a high voltage was applied it produced a florescent glow.

How Were They Discovered

To further observe the rays he positioned a screen in front of the tube. He began placing various objects between the screen and the tube that was emitting the X-rays.

He discovered that the rays or “invisible light” passed right through pieces of black paper and thin sheets of aluminum and copper but that the light did not pass through blocks of lead and his bones, and instead these objects casted shadows on the screen. This is because these objects have higher density so there is less space between their atoms for the rays to pass through.

This is a representation of the lead block experiment.

How X-Rays Work

When electrons are emitted from the cathode and move towards a piece of metal inside the tube. The electrons will collide with the atoms of the metal target and decelerate rapidly. If the electrons have enough energy they can knock an electron from an inner shell to outer shell. When the electron drops back down to the inner shell a photon, or x-ray, is emitted.

Just incase this does not make sense here is a video:

http://www.youtube.com/watch?v=IRBKN4h7u80

X-Rays

Before X-Rays were discovered Before they were discovered no such thing existed in

the physical world. When doctor’s diagnosed broken bones, tumors, and

bullet locations it was all based on their best guess, and physical examinations.

This could be very painful for patients. Think about somebody just squeezing your broken leg until they could find the place of the break.

Rumor has said that an Italian Surgeon, Guido Lanfranc used to check for breaks in a skull by placing a string between patients teeth and plucking it out. If it made a musical note the skull was in tact. If was dim or of toned it showed a broken bone.

Shortly After the Discovery

Röntgen began using his discovery to do his own X-rays on things such as his wife's hand, and weights in a box.

Other scientists began to replicate the experiment because it was easy using a cathode tube.

Interest in the rays began to increase and many magazines, and newspapers began reporting on them. People were very fascinated by the discovery although a few feared it, and that it would allow strangers to see through walls, which is now known to be inaccurate.

Röntgen’s first x-ray of his wife’s hand

How X-Rays Changed Society The most important and

obvious impact of the x-ray is its use in medicine. They are used for broken bones, teeth, internal organs, tumors, etc. They have become the most reliable and widely spread tool for diagnosing internal problems.

Hard x-rays, which have very high frequency rays, are used for radiotherapy for cancer patients.

X-ray machines have also helped greatly with security, like the security scanners used to examine bags at airports.

How X-rays Changed Society They are used to inspect

canned foods on a conveyor belt in factories. X-rays will beam into the can and if it is not properly filled or has a foreign substance in it an alarm will be set off and the can will be removed. Similar technique is used in many factories for various products.

They have also been used in science to learn about the different structures of matter, especially crystals

Works cited

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“The Discovery of X-Rays.” NDT Resource Center. NDT, n.d. Web. 20 Feb. 2012. <http://www.ndt-ed.org/ EducationResources/ HighSchool/ Radiography/ discoveryxrays.htm>.

“History of Radiography.” NDT Resource Center. NDT, n.d. Web. 20 Feb. 2012. <http://www.ndt-ed.org/ EducationResources/ CommunityCollege/ Radiography/ Introduction/ history.htm>.

How X-Ray Cathode Tubes Work. YouTube. YouTube Inc. , 12 Nov. 2009. Web. 20 Feb. 2012. <http://www.youtube.com/ watch?v=IRBKN4h7u80>.

“Xray.” How Stuff Works. HowStuffWorks Inc., 2012. Web. 20 Feb. 2012. <http://science.howstuffworks.com/ dictionary/ physics-terms/ xray-info2.htm>.

“X-Ray Machine.” Medical Discoveries. Advameg Inc, 2012. Web. 20 Feb. 2012. <http://www.discoveriesinmedicine.com/ To-Z/ X-Ray-Machine.html>.

“X-Rays.” NobelPrize.org. Nobel Media, 15 May 2001. Web. 20 Feb. 2012. <http://www.nobelprize.org/ educational/ physics/ x-rays/ index.html>.

“X-Ray Tubes.” Hyper Physics. AAPT, 2000. Web. 20 Feb. 2012. <http://hyperphysics.phy-astr.gsu.edu/ hbase/ quantum/ xtube.html>.