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Thread: Radioactivity & Alpha Decay

  1. #1 Radioactivity & Alpha Decay 
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    Here is an excerpt from this article.

    WHEN THE FRENCH PHYSICIST Henri Becquerel (1852-1908) discovered “his” uranium rays in 1896 and when Marie Curie began to study them, one of the givens of physical science was that the atom was indivisible and unchangeable. The work of Becquerel and Curie soon led other scientists to suspect that this theory of the atom was untenable. Scientists soon learned that some of the mysterious “rays” emanating from radioactive substances were not rays at all, but tiny particles.
    What was the experiment which allowed Becquerel to sense 'rays' emitting from uranium? And how did Becquerel isolate uranium to begin with?

    Eventually I'd like to know what the experiment was that lead them to believe that the rays were actually particles. But I don't want to get ahead of myself.



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  3. #2  
    The Doctor Quantime's Avatar
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    I think it was from radium or something, protons being given off as alpha decay, but I'm a little rusty on this.


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    Quote Originally Posted by svwillmer
    I think it was from radium or something, protons being given off as alpha decay, but I'm a little rusty on this.
    An alpha particle is equivalent to a helium nucleus, not a proton. So, technically, the decaying particle loses protons, but you can't say its 'giving off protons.'

    Basically, one day, Becquerel noticed that a photographic plate stored near his uranium had become exposed. To see if it was actually the uranium that had caused this, he stuck a chunk of uranium in a dark drawer with a photographic plate, and sure enough, the plate was exposed by the radiation from the uranium. Becquerel wasn't actually the one to first isolate uranium, that was Eugene-Melchior Peligot, 55 years before Becquerel did his thing with it.
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    What was the experiment which allowed Becquerel to sense 'rays' emitting from uranium? And how did Becquerel isolate uranium to begin with?
    Becquerel's first encounter with radioactivity was quite by accident. He discovered that photographic plates, stored in a drawer, were exposed and ruined. He then proceeded to re-enact the situation, removing items from the drawer, one at a time, until he concluded that a sample of uranium salts stored in the drawer had caused the exposure of the plates.

    By placing a small metal maltese cross between the uranium and the plates he obtained an image of the cross. Thus he concluded the uranium was giving off some sort of rays (as opposed to say, a mystery gas) that exposed the plates.

    Much later he showed that his rays could be deflected by electric and magnetic fields. This proved they were actually a steam of charged particles.
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    Administrator KALSTER's Avatar
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    Just for the sake of clarity: Alpha radiation = helium nucleus (2protons and 2 neutrons); Beta radiation = electron (neutron decay into a proton) and Gamma radiation = gamma rays (electromagnetic radiation)?
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    Quote Originally Posted by KALSTER
    Just for the sake of clarity: Alpha radiation = helium nucleus (2protons and 2 neutrons); Beta radiation = electron (neutron decay into a proton) and Gamma radiation = gamma rays (electromagnetic radiation)?
    Well done. You'll never guess what delta radiation is.
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  8. #7  
    Administrator KALSTER's Avatar
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    I give up.....
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
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    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
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  9. #8  
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    Science forum spamming .
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  10. #9  
    Administrator KALSTER's Avatar
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    I thought that was Alpha-Sigma-Sigma radiation?
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
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