Science pdf 2

Discovery of the Atoms

By Jennifer Kim

Friday, November 4, 2011

Rutherford

• Rutherford was a New Zealand scientist, he discovered the structure of the atom with Niel Bohr. It is known as the Rutherford-Bohr Theory of Atomic Structure.

• One of his experiment was, which he shot relatively large, charged particles called the “Alpha particles” at a thin gold foil. Through this project, he found the particles passing directly through the foil but came off at odd angles. By this result, Rutherford concluded that each atom was mostly empty space with dense region (central mass) in positive charge.

• However, he made an serious flaw that electrons needed to orbit, but his analysis of energy were made when an electron dropped from a higher energy orbit to a lower energy orbit. This doesn’t make the orbit hold up the atoms. So, he wasn’t able to get the best result out of his experiment of understanding the atom.


Who is Niels Bohr?• Niels Bohr focused on researching the structure of the atom, and completed

the structure at 1913.

• Niels Bohr introduced the theory of electrons traveling around the atom’s nucleus, only in discrete orbits which did not emit radiation. Which means electron moves to a higher orbit with larger radius, absorbing the radiation.

• He also introduced that electrons could drop from a higher-energy orbit to a lower one, light quantum of separate energy. This is the basis for quantum theory.

• He also described the Periodic Table, and that nucleus as a compound structure.

• While he was traveling to the United States, he immediately came up with the theory that the rare uranium isotopes 235 are fissionable by the slow neutrons. However, isotope 238 cannot. Isotope: forms of same elements with equal numbers of proton, but different neutrons in nuclear.

• During his time for understanding how to make Atomic bomb, he was disturbed by escaping the invasion of Nazis in the World War II. His family was half Jew, and escaped to Denmark then Sweden.

Bohr’s atomic models form World Book Encyclopedia

(1999 edition)


J J Thomson

• J J Thomson is scientist from England, who were honored for researching the discharge of electricity in gases. He was the youngest and the third Cavendish Professor with James Clerk Maxwell (who created the basic equations of electromagnetism).

• He made many important experiments on electromagnetism and atomic particles, such as creating the “cathode ray tube.” It is a vacuum tube containing electron gun with the source of electrons. This is the move and deflect the electron beam in order to show images in form of light.

• His experiment creation were made with simpler materials and bad quality, which gave him struggles to understand the result. The days back then, didn’t have the developed technology as it is today. So the materials were a little in-functional Finally, he proved that the negative charge and the ray are inseparable and twisted together.


John Dalton

• John Dalton was a scientist who worked and focused on the behavior and properties of gases.

• John Dalton worked on experiments which proved that the understandings of gas and the elements were used to find out the atomic weight of each element.

• John Dalton’s performed experiments were well done, but he did not know about their structure. Which he knew his result will be something fundamental.

John Dalton's Original Table of Atomic Weights


Democritus

• Democritus, known as the ‘laughing philosopher’ because of his importance on the value of ‘cheerfulness,’ he was one of the two founders of ancient atomist theory.

• He was a philosopher. Philosophers are people who think about the world, including the atoms. However, he studied many things other than atoms. Such as, animals, plants, weather, and stars.

• He found that there were infinite number of different types of atoms. They were kinds of shape and size which were made from the same stuff. So how the substance was solid or liquid, hot or cold, spicy or sweet, he thought they were all because of the appearance of atoms.

• However, his limitation was that he didn’t do any experiments or have the equipments to. He didn’t have the special microscope to see the atoms, so he had to invent with his own imaginations. It was also too old back then, which was harder to discover new things on their own.


Global Issue of Atoms• Electricity from: Nuclear Power “Are they really

necessary?”

• These nuclear power plants are fueled by uranium, this naturally occurs in the Rocky Mountains, countries such as Canada, Australia, and South Africa.

• The energy is stored in uranium atoms and it makes the nuclear power possible.

• The nuclear reaction generates heat to generate electricity, which is like fossil fuels; it is an finite non-renewable resource.

• We need them for radioactive materials, for treatments in medicine, radiography, to remote locations, space applications, and finally for food irradiation.


Benefits and Limitations

• Even though they don’t generate air pollutants (sulfur dioxide, carbon dioxide, nitrogen oxides), the operation of nuclear power result in environmental impacts (air emissions). Their air emissions are not similar of those fossil plants, but they release small amounts of airborne radioactive gasses.

• So does the nuclear plants that works upon water, it will impact water resources, aquatic habitats, and fish.

• The radioactive wastes from the nuclear power, risks health and will be stored for centuries.


Environmental

• This is an issue that people all over the world have. The Nuclear power made by uranium is in only little way of carbon emissions. The single nuclear power plant can generate so much electricity, with a long life span. However, toward the environment, the process of mining Uranium for nuclear power causes harm. It destroys the landscape and releases radioactive substances. The chemicals during the process can leak into groundwater.


EnvironmentsAlso, except the generation of nuclear fuel, they also involve carbon emission in process. The most recent issues from today, Nuclear power can bring out “Chernobyl.” It is when the radiation levels are every where elevating normally from 10 to 100. It can also harm the water for the coolings systems of the plants, and produce radioactive wastes. Nuclear Powers can be a big use, but a very big harm towards our environment.

Japan’s Nuclear

Radiation


Economic

• The cost of building a nuclear power plants is an expensive project, which requires good deal of taxpayer money. The long planning and building will invariably cost a lot. Also, the after cost of this project will be huge. “Imagine” the cost involved with storing nuclear waste for thousands of years. How much will that be? Sometimes, this project can be part of wasting money for the countries.


Imagine..-Human Health

Problems: vomiting,headache,some loss of white blood

cells,nausea

Thousands of people are sick from this


• Works Cited

"Chernobyl Legacy Lingers in Britain." Green Living Tips - a More Environmentally Friendly Life. Web. 03 Nov. 2011. <http://www.greenlivingtips.com/blogs/389/Chernobyl-legacy-lingers-in-Britain.html>."Electricity from Nuclear Power." Power Scorecard Homepage. Web. 03 Nov. 2011. <http://www.powerscorecard.org/tech_detail.cfm?resource_id=7>."History of Atoms." NoBeliefs.com (Freethinkers). Web. 03 Nov. 2011. <http://nobeliefs.com/atom.htm>."J. J. Thomson's Cathode Ray Experiment." The Scientific Method, Science, Research and Experiments. Web. 03 Nov. 2011. <http://www.experiment-resources.com/cathode-ray.html>.


http://www.greenlivingtips.com/blogs/389/Chernobyl-legacy-lingers-in-Britain.html






http://www.powerscorecard.org/tech_detail.cfm?resource_id=7




http://nobeliefs.com/atom.htm

http://nobeliefs.com/atom.htm

http://www.experiment-resources.com/cathode-ray.html




"John Dalton’s Atomic Theory." Universe Today — Space and Astronomy News. Web. 03 Nov. 2011. <http://www.universetoday.com/38193/john-daltons-atomic-theory/>.

"Nuclear Energy | Clean Energy | US EPA." US Environmental Protection Agency. Web. 03 Nov. 2011. <http://www.epa.gov/cleanenergy/energy-and-you/affect/nuclear.html>.

"Rutherford-Bohr Model | Radiation Protection | US EPA." US Environmental Protection Agency. Web. 03 Nov. 2011. <http://www.epa.gov/radiation/understand/rutherford.html>.

Book Source:

Pasachoff, Naomi. Niels Bohr Physicist and Humanitarian. United States of America: Enslow, 2003. Print. Great Minds of Science.


http://www.universetoday.com/38193/john-daltons-atomic-theory/




http://www.epa.gov/cleanenergy/energy-and-you/affect/nuclear.html




http://www.epa.gov/radiation/understand/rutherford.html




Thank You :)


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