Purpose: To simulate radioactive decay and determine the half-life of a radioactive substance. Procedure. 1. Count out kernels of popcorn. Since its development over 30 years ago, radiocarbon dating has proven to be an .. The dated corn sample, a single uncharred cob with kernels attached, was . A simple way to simulate radioactive decay is by making popcorn. Popcorn starts out as unpopped “parent” kernels we'll call “kernelite, (Ke).” Heating starts the.

### Dating Popcorn | Earth Science Week

The first time I did this, I made a pretty big mess on the lab bench. After the initial "decay" and if your class isn't too large, pop some more with the lid on so that students can enjoy the demonstration too Teaching Materials Popcorn popping is a great analogy for the spontaneity of radioactive decay. It is impossible to predict which kernel will pop first. If you can, bring in a hotplate, a small pan, oil and some popcorn.

Put the oil in the pan with a few kernels of popcorn. Ask the students to predict which will pop first. What are variables that control whether a kernel of corn will pop? What happens to the kernel of corn when it does pop? Can it go back to the way it was before it popped? Assessment A quick check of whether the students picked up the ideas of unpredictablitly and irreversibility can be done in one of several ways.

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A one or two question quiz, with questions that relate to the goals of this exercise. A short group discussion in small groups or as a whole class about the analogy of popcorn and how it is like radioactive decay. If you are moving on to talk about radiometric dating or half-life, intersperse your lecture with questions about the analogy References and Resources Lisa Tauxe at Scripps has another discussion -- you have to scroll down about halfway to What does popcorn have to do with it?

Radioactive Decay 5 5 Suppose you put kernels of popcorn in a popcorn popper and raise the temperature to a constant level hot enough for the kernels to begin popping.

What would happen after a second interval? Create the Excel spreadsheet shown below to find out! Cell C3 is the number of kernels you start with in the popper. Cell C4 is the probability that a kernel will pop in a second interval.

Column B lists the numbers of seconds that have passed. Remember we are thinking in second intervals. Set up Column C to calculate the number of kernels remaining unpopped after each second period. So, why am I supposed to be thinking about popcorn? First, create fifteen second intervals in Column B. Create Column D to look at the ratio of popped to unpopped kernels.

This is simply the number of kernels remaining after each second interval divided by the number of kernels you started with. What happens in the second intervals after the first one?

### Radioactivity Lab with Popcorn Kernels by Brad Alcock on Prezi

The half-life of the popcorn is the time at which half of the kernels remain unpopped. Use your trendline equation to determine the half-life of our popcorn sample set. Looking at Popcorn Popping Graphically 8 8 In the last slide, we determined the function that describes the number of our unpopped popcorn kernels over time: N o is the starting number of kernels.

**Radiometric Dating (Dr. Jason Lisle)**

N is the number of unpopped kernels at time t. Start thinking about your answer to this question and we will explore it in depth in the next module.

## Using Popcorn to Simulate Radioactive Decay

The Popcorn Popping Function 9 9 Interesting question. Just as a kernel pops into a piece of popcorn… So does a radioactive atom of a parent isotope decay to a radiogenic atom of the daughter isotope. What we know is only the probability that it will occur in the next time interval!

This probability is consistent over time and is also known as the decay constant commonly denoted as. There are many excellent references on radiometric dating and its context. We particularly recommend G. See particularly, Chapter 4: How Radiometric Dating Works. Answer the question on Slide 7: Change your values and hand in this spreadsheet with a graph of the new example.

We have discussed the half-life of our popcorn kernels. Thinking in the same way, what do you think the third-life of the kernels is?