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1 of 39© Boardworks Ltd 2007 Nuclear Fission Objectives Be able to describe what nuclear fission is and what a chain reaction is 27 April 2015 Nuclear.

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Presentation on theme: "1 of 39© Boardworks Ltd 2007 Nuclear Fission Objectives Be able to describe what nuclear fission is and what a chain reaction is 27 April 2015 Nuclear."— Presentation transcript:

1 1 of 39© Boardworks Ltd 2007 Nuclear Fission Objectives Be able to describe what nuclear fission is and what a chain reaction is 27 April 2015 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. Describe what the bold words mean. Why does it talk about marbles? 10 MINUTES!! Copy the objectives then read the passage and answer the questions.

2 2 of 39© Boardworks Ltd 2007 Outcomes All students should be able to describe what a fission reaction and chain reaction is. Most students should be able to describe how a fission reactor works and how it is kept safe. Some students should be able to describe the dangers of nuclear and evaluate models to describe chain reactions, come up with their own and argue why we should or should not use nuclear power.

3 3 of 39© Boardworks Ltd 2007 Nuclear fission occurs when a stable isotope is struck by a neutron. The isotope absorbs the neutron, becomes unstable and then splits apart, releasing large amounts of energy. What is nuclear fission? The fission of 1 kilogram of uranium-235 releases more energy than burning 2 million kilograms of coal! Unlike natural radioactive decay, fission is not a natural event. Isotopes that undergo fission include uranium-235 and plutonium-239. These isotopes can both be used in nuclear reactors and in nuclear weapons.

4 4 of 39© Boardworks Ltd 2007 Fission Introduction into Nuclear Fission UIKuv8http://www.youtube.com/watch?v=N7C14 UIKuv8

5 5 of 39© Boardworks Ltd 2007 What happens in nuclear fission?

6 6 of 39© Boardworks Ltd 2007 How does nuclear power work?

7 7 of 39© Boardworks Ltd 2007 What’s a chain reaction? When one action creates a chain that makes other actions occur without further stimulus: Dominoes FIRE: PING PONG? Evaluate: Which model is best to describe a nuclear chain reaction? Why?

8 8 of 39© Boardworks Ltd 2007 What is a chain reaction? Nuclear fission results in a chain reaction because each time a nucleus splits it releases more neutrons, which can go on and cause more fission reactions to occur... and so on. +   +       + + This is why a chain reaction releases a lot of energy so rapidly. If a chain reaction is uncontrolled, heat builds up very quickly. A chain reaction must be controlled to maintain a steady output of heat.

9 9 of 39© Boardworks Ltd 2007 What happens in a chain reaction?

10 10 of 39© Boardworks Ltd 2007 For nuclear fission to start in a reactor, a uranium-235 atom must absorb a low speed neutron. High speed neutrons are not as readily absorbed by uranium nuclei. How are neutrons controlled? However, high speed neutrons are released during fission. control rod fuel rod graphite core water carrying away heat The reactor’s graphite core slows down the released neutrons so the chain reaction can keep going. Control rods made of boron absorb excess neutrons to prevent chain reactions getting out of control.

11 11 of 39© Boardworks Ltd 2007 Nuclear Fission Task: Summarise the 5 most important points from the information given to you. You MUST describe what a fission reaction and draw what a chain reaction is. You SHOULD describe how a fission reactor works and how it is kept safe. You COULD describe the dangers of nuclear. control rod fuel rod graphite core water carrying away heat concrete

12 12 of 39© Boardworks Ltd 2007 Review and Revise Self Assess You MUST describe what a fission reaction and chain reaction is. You SHOULD describe how a fission reactor works and how it is kept safe. You COULD describe the dangers of nuclear.

13 13 of 39© Boardworks Ltd 2007 Pros and cons of using nuclear fission

14 14 of 39© Boardworks Ltd 2007 Review All students should be able to describe what a fission reaction and chain reaction is. Most students should be able to describe how a fission reactor works and how it is kept safe. Some students should be able to describe the dangers of nuclear and evaluate models to describe chain reactions, come up with their own and argue why we should or should not use nuclear power. Describe which outcomes you have met today and what skills you have used to achieve them. Creative Thinker Self Manager Reflective Learner Effective Participator Independent Enquirer Team Worker

15 15 of 39© Boardworks Ltd 2007 Wordsplat/Bingo FissionNeutronTurbine Control RodUraniumNucleus Chain Reaction Fusion Plutonium

16 16 of 39© Boardworks Ltd 2007 Wordsplat/Bingo FissionUranium Chain Reaction PlutoniumNeutronNucleus TurbineFusionControl Rod

17 17 of 39© Boardworks Ltd 2007 Wordsplat/Bingo FusionUraniumNucleus FissionNeutron Chain Reaction PlutoniumTurbineControl Rod


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