Radioactive isotope dating problems
To do this lesson and understand half-life and rates of radioactive decay, students should understand ratios and the multiplication of fractions, and be somewhat comfortable with probability.
These were long on armchair speculation and short on substantive supporting evidence.
Some evidence is also presented to show that radiometric results that are in agreement with the accepted geological time scale are selectively published in preference to those results that are not in agreement.
The geological time scale and an age for the Earth of 4.5 b.y.
Net on Radioactive Lenses (gamma levels..) Radioactive Fed-5s (slight..) Radioactive Optics Posting (WJM) Radioactive Pentax Lens (GM tube sound file..) Romancing the Rare Earths On Enhancing Filters by Howard Ross U. Govt Surplus "Hot" Cameras and Lenses You will find two kinds of radioactive lenses - those that were contaminated and sold as government surplus, and those that are naturally "hot" or radioactive due to the radioactive elements or radioactive impurities used in their manufacture. I am assuming that heavily contaminated and radioactive government surplus items end up in government low level radioactive waste land-fills or other burial sites.
If you want to buy some slightly radioactive lenses and cameras, the U. So if your government surplus bargain camera or lens is contaminated, it is probably only "lightly" contaminated. "Hot" Lenses made from Radioactive Materials Many specialty optical glasses have radioactive elements added to them, either as desired components or as impurities in the mixtures being used.
The mathematics of inferring backwards from measurements to age is not appropriate for most students.