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# 7.2. Nuclear Reactions

We learnt at GCSE that some isotopes of different elements are radioactive, Carbon-14, Uranium-235 etc. Why do some elements have halflives on the order of millions of years, whereas some decay withing milliseconds? We know that the nucleus is held together by the strong nuclear force, and the nucleon composition (numbers of protons and neutrons) of the nucleus determines the stability of these nuclei. This section looks a little bit into these ideas, and how we can calculate energy released through fission or fusion using Einstein's famous equation, E = mc².

Before we start, I love this video by Veritasium - trying to answer the question of 'What is the most radioactive place on Earth?'.

The section has been divided up as follows:

Nuclear Stability

#### Nuclear Stability

We already know some nuclei are stable and some are unstable. We also know that depending on the composition of the nucleus, the nucleus may decay through alpha, beta or gamma emission. Here we explore a little bit into these ideas. Crash Course have a nice little intro to get us started.

## Video Lessons

 Khan Academy Nuclear Stability and Decay Physics Online Isotopes Intro

## Resources

 IB Physics Topic 7 Notes IB-Physics.net Chapter 7 Summary IB Revision Notes Mr. G 7.2 Teaching Notes 7.2 Student Notes Physics and Maths Tutor Particles Definitions Particles Key Points Particles Detailed Notes Particles Flashcards A Level Resources - content slightly different

## Questions

 Cambridge University Press Topic 7: Add Qs Topic 7: Add Qs MS Topic 7: MCQs CUP Website Link Freely available online Grade Gorilla 7.2 (Nuclear Equations) MCQ Topic 7 (Nuclear) End Quiz Quick IB Specific Mixed MCQs Mr. G 7.2 Formative Assessment Topic 7 Summary Qs IB Specific Questions
Binding Energy and Mass Defect

#### Binding Energy and Mass Defect

The key points of this section are explained quite nicely here:

This section is all about getting your head around the idea of a nuclear binding energy - the energy given out when a nucleus forms. Due to Einstein's famous equation, E=mc², this means that a bound nucleus of, for example, Helium (made of 2 protons, 2 neutrons) has a smaller mass than those same nucleons if they were free.

The reason this is idea of binding energy is significant is because it allows us to understand how we may produce energy from nuclear fusion (the fusing of smaller nuclei to form a larger nucleus) and nuclear fission (the splitting of a large nucleus to form daughter nuclei).

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It is important that we are able to understand the following plot, and the significance of Fe-56.

Fe-56 has the highest binding energy per nucleon.

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To the left of Fe-56, fusion is able to occur to release energy. To the right, fission will release energy.

## Video Lessons

 Chris Doner Nuclear Binding Energy IB Specific Gradepod Binding Energy per Nucleon IB Specific Khan Academy Mass Defect/ Binding Energy Science Shorts Binding Energy Study Nova Binding Energy Per Nucleon

## Resources

 IB Physics Topic 7 Notes IB-Physics.net Chapter 7 Summary IB Revision Notes Mr. G 7.2 Teaching Notes 7.2 Student Notes Physics and Maths Tutor Particles Definitions Particles Key Points Particles Detailed Notes Particles Flashcards A Level Resources - content slightly different

## Questions

 Cambridge University Press Topic 7: Add Qs Topic 7: Add Qs MS Topic 7: MCQs CUP Website Link Freely available online Dr French's Eclecticon Nuclear Physics Nuclear Physics Solutions Link to Dr French's Site Extension: Pre-University Material Grade Gorilla 7.2 (Nuclear Equations) MCQ Topic 7 (Nuclear) End Quiz Quick IB Specific Mixed MCQs Isaac Physics Energy in Nuclear Reactions Mr. G 7.2 Formative Assessment Topic 7 Summary Qs IB Specific Questions
Fission and Fusion

## Fission and Fusion

In this section, you should be able to link the above ideas of mass defect to calculate the energy produced through fission and fusion.

However, it is worth refreshing your memory on the key aspects of fission and fusion, so flick through the following resources.

PHET have a neat simulation looking at Uranium fission and the nuclear chain reaction.

PhD Comics have a nice YouTube video discussing fusion energy

## Video Lessons

 Chris Doner Fission and Fusion IB Specific Science Shorts Fission and Fusion

## Resources

 IB Physics Topic 7 Notes IB-Physics.net Chapter 7 Summary IB Revision Notes Mr. G 7.2 Teaching Notes 7.2 Student Notes Physics and Maths Tutor Particles Definitions Particles Key Points Particles Detailed Notes Particles Flashcards A Level Resources - content slightly different

## Questions

 Cambridge University Press Topic 7: Add Qs Topic 7: Add Qs MS Topic 7: MCQs CUP Website Link Freely available online Dr French's Eclecticon Nuclear Physics Nuclear Physics Solutions Link to Dr French's Site Extension: Pre-University Material Grade Gorilla 7.2 (Nuclear Equations) MCQ Topic 7 (Nuclear) End Quiz Quick IB Specific Mixed MCQs Mr. G 7.2 Formative Assessment Topic 7 Summary Qs IB Specific Questions