# Radioactive dating lab pennies worth Db Radioactive atoms decay, emitting radiation. value to half of that value can be measured and is called the half-life of the radioactive isotope. The activity uses pennies and dice to represent radioactive isotopes with different half-lives. The pennies that landed heads-up will represent decayed nuclei, the In the year , an archaeology team unearths pottery and is using this isotope for radiometric dating to place the age of the pottery. Graph the data; this graph should resemble the graph from your lab. Notice that you have a y- value at x = 0. This is. Relative dating gives an approximate age of something compared to some other Each penny represents an atom in the radioactive element Carbon old. Only a few rocks have been found to be that old. Why might some rocks be

### Penny Decay Lab Document

Penny Decay web 1 If you plot the natural logarithm of the concentration of A, ln[A], versus time, you will get a graph which is a straight line with a slope equal to -k. See the graph below. In nuclear decay, the rate is proportional to the number of nuclei present. The number of nuclei to decay in a given period of time is always proportional to the number of nuclei left. Nuclear decay is an independent nucleus-by-nucleus process. The probability that a given nucleus will decay in a certain time is constant and independent of other nuclei and the surroundings.

It is a random event and not influenced by factors such as temperature or pressure. In place of the concentration of A you can substitute the number of nuclei present, N. You will construct a graph of the number of pennies left after a given amount of time numbers of shakes versus time and a graph of the natural logarithm of the number of pennies remaining versus time.

## Penny Decay Lab Document

You will calculate the rate constant and the half-life for the process. Obtain a box with a lid containing about pennies.

Penny Half-Life Lab

Count the initial number of pennies in the box. Record this value in the Data Table at shake 0. Put the pennies back in the box. Close the box and shake the box several times to thoroughly mix the pennies.

### Half-Life : Paper, M&M’s, Pennies, or Puzzle Pieces - ANS

Open the box and carefully remove the pennies that are face-up. Be careful not to turn over any of the pennies. Count the number of face-up pennies. Record this value in the Data Table at shake 1. Subtract the number of pennies removed from the initial number of pennies to give the number of pennies remaining. Record this value in the Data Table at shake 2.

## In the Classroom

Subtract the number of pennies removed from the number of pennies remaining after shake 1 to give the number of pennies remaining. Penny Decay web 3 8. Flows, Cycles, and Conservation Objectives Students try to model radioactive decay by using the scientific thought process of creating a hypothesis, then testing it through inference. It is a great introduction to the scientific process of deducing, forming scientific theories, and communicating with peers. It is also useful in the mathematics classroom by the process of graphing the data. Seeing this connection will help students to understand how scientists can determine the age of a sample by looking at the amount of radioactive material in the sample.

To define the terms half-life and radioactive decay To model the rate of radioactive decay To create line graphs from collected data To compare data To understand how radioactive decay is used to date archaeological artifacts Background Half-Life If two nuclei have different masses, but the same atomic number, those nuclei are considered to be isotopes.

Isotopes have the same chemical properties, but different physical properties. An example of isotopes is carbon, which has three main isotopes, carbon, carbon and carbon All three isotopes have the same atomic number of 6, but have different numbers of neutrons. Carbon has 2 more neutrons than carbon and 1 more than carbon, both of which are stable. Carbon is radioactive and undergoes radioactive decay. Radioactive materials contain some nuclei that are stable and other nuclei that are unstable.

Not all of the atoms of a radioactive isotope radioisotope decay at the same time. Rather, the atoms decay at a rate that is characteristic to the isotope. The rate of decay is a fixed rate called a half-life. The half-life of a radioactive isotope refers to the amount of time required for half of a quantity of a radioactive isotope to decay. Carbon has a half-life of years, which means that if you take one gram of carbon, half of it will decay in years. Different isotopes have different half-lives.