Tuesday, October 5, 2010

Chapter 4: Discovery of Protons

Ernest Rutherford,a British chemist, was known as the father of nuclear physics. He worked with nuclear physics and experimented with the nucleus and different kinds of atoms.
The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom, along with neutrons, but is also stable by itself and has a second identity as the hydrogen ion, H+. It is composed of three fundamental particles: two up quarks and one down quark.

The Experiment:
After the discovery of the electron in 1897, scientists realized that there must be a positive charge.  He then shot alpha particles through nitrogen gas and observed the charge of the particles that passed through the foil. Any other particles that passed through would fall onto the zinc sulfide screen and create a sparkle. These were all shown to have the same positive change as a proton. Some even came back towards the way they had come from. This showed him that there were even protons in the nucleus because the protons would bounce back off the other protons.

Why he chose this?
In 1919 Rutherford discovered that he could change one element into another by striking it with energetic alpha particles. Rutherford conducted numerous experiments and in every case, hydrogen nuclei were emitted in the process. He saw that the hydrogen nucleus was important to the atomic structure and by 1920, scientists reffered to it as "a proton."

Nuclear transmittion taking place.

"Rutherford bombarded gases with alpha particles."

1. Sawyer/ Assist. Professor of Physics, Louisiana Tech Univ., Dr. Lee. "Who Discovered the Proton? And How Was It Discovered?" Physics and Astronomy Links - PhysLink.com. Web. 05 Oct. 2010. http://www.physlink.com/education/askexperts/ae46.cfm.
2. "Discovery of Protons." Oracle ThinkQuest Library. 1999 ThinkQuest Team. Web. 05 Oct. 2010. <http://library.thinkquest.org/27954/proton.html>.
3. "Ernest Rutherford." Wikipedia, the Free Encyclopedia. Web. 05 Oct. 2010. http://en.wikipedia.org/wiki/Ernest_Rutherford.
4. "Proton." Wikipedia, the Free Encyclopedia. Web. 05 Oct. 2010. http://en.wikipedia.org/wiki/Proton.
5. "YouTube - Rutherford's Experiment: Nuclear Atom." YouTube - Broadcast Yourself. Web. 05 Oct. 2010. <http://www.youtube.com/watch?v=5pZj0u_XMbc&feature=related>.