HW: #1 How did the Atomic bomb change history? (see p. 563) If you were the pilot that dropped the bomb….how would you feel? If you were the pilot, write a letter to your wife about your mission and what you did.
HW: #2 Basic Nuclear Fission: read and answer questions
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Introduction:
Introduction:
¢Nuclear fission is the process of splitting atoms, or fissioning them.
Before we talk about that, however, I would like to discuss marbles. Everyone's played with marbles at one time or another, right? Well, imagine about 200 marbles lying on a flat surface, all jumbled together, and roughly forming a circle. What would happen if someone took another marble and threw it at them? They would fly all around in different directions and groups, right? That is exactly what happens in nuclear fission. The filled circle is like an atom's nucleus. The marble being thrown is like a "neutron bullet". The only differences are that the marbles are protons and neutrons and the protons and neutrons aren't in a filled circle, but in the actual atom are in the shape of a sphere. Of course, an atom is also a bit more complicated than a pack of marbles.
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¢Choosing the Bullet:
¢When we spoke about the marble analogy earlier, we said that the marble being thrown is a like a "neutron bullet". But what does this mean, and why not use another type of particle to "throw" at a nucleus to fission it? Now, let's review the structure of an atom. Remember that an atomic nucleus is made up of positive protons and neutral neutrons? Because of this, the nucleus carries an overall positive charge. So, if we were to launch another particle with a positive charge at a nucleus, it wouldn't get there. Why wouldn't it get there? The answer lies in magnetism. Have you ever used magnets? If you have, you'd know that two like poles of a magnet repel each other. A positive particle and the positive nucleus would repel each other in the same way. The particle is positive. Why? Well, it's composed of two protons and two neutrons. Its positive protons give it a positive charge. Because it's positive, it would get repelled away from another positive nucleus. So, the only thing left is the neutron. The neutron is electrically neutral and thus would not get repelled from a positive nucleus.
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¢Splitting the Uranium Atom:
¢Uranium is the principle element used in nuclear reactors and in certain types of atomic bombs. The specific isotope used is 235U. When a stray neutron strikes a 235U nucleus, it is at first absorbed into it. This creates 236U. 236U is unstable and this causes the atom to fission. The fissioning of 236U can produce over twenty different products. However, the products' masses always add up to 236. The following two equations are examples of the different products that can be produced when 235U fissions:
¢235U + 1 neutron 2 neutrons + 92Kr + 142Ba + ENERGY
¢235U + 1 neutron 2 neutrons + 92Sr + 140Xe + ENERGY
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¢Let's discuss those reactions. In each of the above reactions, 1 neutron splits the atom. When the atom is split, 1 additional neutron is released. This is how a chain reaction works. If more 235U is present, those 2 neutrons can cause 2 more atoms to split. Each of those atoms releases 1 more neutron bringing the total neutrons to 4. Those 4 neutrons can strike 4 more 235U atoms, releasing even more neutrons. The chain reaction will continue until all the 235U fuel is spent. This is roughly what happens in an atomic bomb. It is called a runaway nuclear reaction.
Questions:
Draw a diagram of how Nuclear Fission works. Be prepared to explain it to a partner tomorrow.
Explain the chain reaction that occurs in Uranium 235.
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HW: #3 Review for your Test on World War 2—Thurs/Fri
1.nationalism
2.Propaganda
3.Holocaust
4.Genocide
5.Anti-semitism
6.3 Allies; Allied Powers
7.3 Axis powers
8.Master Race, Aryan ‘race’
9.Adolf Hitler
10.Mussolini
11.Stalin
12.Hitlers vision for Germany
13.Mein Kampf
14.Youth Pledge to Hitler
15.Nuremberg Laws
16.Name the Six Stages of Genocide: Give a specific example from you notes from presentations
17.Einsatzgruppen
18.Kristalnacht
19.Pearl Harbor
20.The Final Solution, 1942
21.Auschwitz Concentration camp
22.D Day
23.Truman
24.Hiroshima, Nagasaki
25.Analyze this work of art: Describe 3 images; what does each symbolize? What is Picasso’s universal message?
Is this due tomorrow??
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