GEORGIA MILITARY COLLEGE

NATURAL SCIENCE DEPARTMENT

ONLINE CAMPUS

LABORATORY 8 RADIATION

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Introduction

This laboratory explored the concept of radioactive decay. Radioactive decay is the process by which unstable atomic nuclei undergo radiation, emitting energy and other elements in the process (Lofts & Evergreen, 2023). Materials with unstable atomic nuclei are radioactive materials. An important benefit of radioactive decay is its use in dating samples to determine when they lived on earth and make predictions on the conditions on earth at the time. Carbon-14 is a radioactive isotope of the element carbon that is commonly used to estimate the age of organisms through the process of radiocarbon dating. Carbon-14 is formed in the environment when cosmic rays interact with nitrogen atoms (N) and nitrogen molecules (N2) (Lofts & Evergreen, 2023). It undergoes rapid oxidization in the atmosphere to form carbon (IV) oxide. Living organisms are continually replenishing their carbon-14 content by exchanging carbon (IV) oxide with the biosphere. This exchange stops when an organism dies and their carbon-14 content begins to decline over time as it undergoes radioactive decay to form Nitrogen-14 atoms (Lofts & Evergreen, 2023). Thus, the older the artefact, the lower its carbon-14 concentration. The process of determining an artefacts age by examining its carbon-14 content is referred to as radiocarbon dating.

The number of caron-14 atoms decaying per unit of time is referred to as the rate of radioactive decay. It is calculated using the formula:

Rate of radioactive decay = k Nt .equation 1

Where Nt is the number of radioactive atoms in the sample at time t, and k is the radioactive decay constant.

The time it takes for one half of the radioactive atoms to decay is defined as the artefacts half-life (denoted as t1/2). It is calculated as:

T1/2 = ln2/kequation 2

T1/2 = 0.693/k; where k is the radioactive decay constant.

Carbon-14 has a half-life of 5,730 years. This implies that concentration of carbon-14 in an artefact is halved over...

This laboratory seeks to use actual data from an experiment to determine the age of sampled artifacts. It has two primary objectives:

i) To understand the concepts of radioactive decay and half-life.

ii) To familiarize with the half-life curve.

Materials and Methods

Preparing the Lab

i) Access the simulation environment through the Radioactive Dating Game tab on the course home page.

ii) On the simulation environment, choose the Half Life tab and click on Carbon-14 from the right menu.

iii) Examine the graph that loads and record the estimated half-life. At this point, one has all they need to perform the lab.

Performing...

…living plants are continually replenishing their carbon-14 supply through uptake of carbon (IV) oxide for photosynthesis. The carbon decay process only begins when an organism dies and stops exchanging carbon-14 with the biosphere.

Conclusion

This laboratory sought to examine the concepts of radioactive decay and half life and to familiarize with the half-life curve. The half-life of two isotopes Carbon-14 and Uranium-238- was estimated using different masses of the respective isotopes. The results showed that an isotopes half-life remained constant regardless of the mass of the tested sample since the decay process is purely radioactive, dictated by the configuration of protons and neutrons, and not physical properties. From the results, Uranium-238 reports a longer half-life than carbon-14 because its nucleus has a more stable configuration and thus decays at a slower rate. In the second phase of the experiment, the carbon content of 6 samples was examined and used to predict each samples age. The results supported the hypothesis that an isotopes carbon content declines over time and hence, older samples generally have lower carbon contents. The older the sample, the lower its carbon content. Living samples, on the other hand, have 100 percent carbon content as they are continually replenishing their carbon-14 concentrations from the biosphere, and decay only begins when one…