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Nuclear Reactions.

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Presentation on theme: "Nuclear Reactions."— Presentation transcript:

1 Nuclear Reactions

2 Standards Know that some atomic nuclei can change, including:
Spontaneous decay Fission Fusion Alpha, beta & gamma radiation

3 Types of Nuclear Reactions
Natural Radioactive Decay Nuclear Fission Nuclear Fusion

4 Natural Radioactive Decay
Occurs naturally in some elements, especially heavy elements (atomic #83 & higher) Nucleus breaks down naturally, releasing particles & energy Used for radioactive dating

5 Types of Natural Radioactive Decay
3 most common types of radioactive decay Alpha decay Beta decay Gamma decay

6 Types of Natural Radioactive Decay
Alpha decay – an alpha (α) particle is emitted from the nucleus. Alpha particle has 2 p+ & 2 n0 (same as a helium nucleus) Least energetic of the 3, can be blocked by a piece of paper or surface of skin

7 Types of Natural Radioactive Decay
Beta decay - a beta () particle is emitted from the nucleus. Beta particle is an e- formed from decomposition of a n0 into a p+ & e- Can be stopped by aluminum foil or thin wood

8 Types of Natural Radioactive Decay
Gamma decay – emission of a high energy photon (particle of light) Will only be stopped by several meters of concrete or several centimeters of lead Will pass through human body and are very dangerous

9 Each type of radiation can penetrate materials differently

10 Nuclear Fission Heavy element decays (nucleus splits), releasing particles (n0) and large amounts of energy 1st atomic bombs were fission bombs: Little Boy (fission of uranium) – dropped on Hiroshima, Fat Man (fission of plutonium) – dropped on Nagasaki Present-day nuclear power plants work by fission

11 Fat Man Little Boy Nagasaki

12 Nuclear Fusion Nuclei of small atoms combine to form a larger nucleus (usually hydrogen nuclei combine to form helium), releasing huge amounts of energy in the process Core of our sun is a fusion reactor Appealing as energy source, but difficult to achieve high temperatures necessary and to contain reaction Much safer than fission reactors

13 Our Sun photo: SOHO Tokamak (fusion reactor)


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