What do Frederick Soddy's radioactive materials from the first decade of the 20th century look like?
The samples are all in small sealed glass tubes containing small quantities of powders, or in one case, a metal tube. The maximum dose the samples deliver varies from insignificant (Sample 1, labelled actinium), to 29 millisieverts per hour (No 4, encased in lead). Many of the glass tubes are smoky, violet or purple, but this is due to radiation damage to the glass - the actual contents are pure white.
The most significant sample may well be No 6, which is labelled "Mesothorium" in Soddy's own hand. Soddy's work which lead to his concept of isotopes involved mixing radium (Marie Curie's 226Ra derived from the uranium decay series) with barium salts, and "mesothorium" (now known as 228Ra derived from the thorium decay series) and trying to separate these mixtures by chemical means. Others had also tried this, but Soddy decided that the failure to separate them was not due to inadequate chemical techniques, but rather because mesothorium and radium were the same chemical element, occupying the same place in the periodic table. This insight, and the word isotope, were pubished in his letter to Nature on 4th December 2013.
It is almost certain that this is one of the samples Soddy used in developing this key concept.
The samples are all in small sealed glass tubes containing small quantities of powders, or in one case, a metal tube. The maximum dose the samples deliver varies from insignificant (Sample 1, labelled actinium), to 29 millisieverts per hour (No 4, encased in lead). Many of the glass tubes are smoky, violet or purple, but this is due to radiation damage to the glass - the actual contents are pure white.
The most significant sample may well be No 6, which is labelled "Mesothorium" in Soddy's own hand. Soddy's work which lead to his concept of isotopes involved mixing radium (Marie Curie's 226Ra derived from the uranium decay series) with barium salts, and "mesothorium" (now known as 228Ra derived from the thorium decay series) and trying to separate these mixtures by chemical means. Others had also tried this, but Soddy decided that the failure to separate them was not due to inadequate chemical techniques, but rather because mesothorium and radium were the same chemical element, occupying the same place in the periodic table. This insight, and the word isotope, were pubished in his letter to Nature on 4th December 2013.
It is almost certain that this is one of the samples Soddy used in developing this key concept.
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