Carbon Dating, Food Irradiation, Helium And Lithium Essay Samples

Although Helium and Lithium only differ in one element, differ in their chemical and physical behavior. Helium is a noble gas which is found in group 18. Helium has only one electron shell which contains two electrons. The complete shell makes helium an inactive element and does not combine with other elements. Lithium, on the other hand, has three electrons meaning it has two shells. The first shell in lithium, has 2 electrons, and the second has only 1 electron. The second shell is not complete and therefore very active making lithium to combine readily with other elements. The free electron in the outer shell allows lithium to make bonds quickly especially with atoms that require one electron to complete their shells.
Food is irradiated with gamma rays from a Cobalt-60 source in order to reduce spoilage organisms by delaying ripening, extend shelf-life and inhibit sprouting. Irradiation is also done for killing pathogens such as listeria, salmonella and E.coli that are food-borne. Cobalt-60 is preferred because up to 95% of the emitted energy is available for use. The rays penetrate deep; the resulting dose in the food product is substantially uniform, and it poses little risk to the environment. The irradiated food does not become radioactive because the gamma radiation does not generate any nuclear change on the food products. The gamma rays only cause ionization of atoms and affect the environment causing the microbes in the food to die.
Carbon dating relies on C14 for dating materials. The C14 has a half-life of 5730 years give or take 40 years. The method is, therefore, inappropriate for dating of materials that are a few years old. Radiocarbon dating is however appropriate for dating materials that are thousands of years old. The method is however not appropriate for dating materials that are millions of years old. The carbon in the material will have been completely depleted because half of the carbon disappears after every half-life.