How This Works

This digital simulation models the same radioactive decay process as the physical coin lab. You start with 100 virtual "coins" — each one representing a radioactive parent atom.

When you shake the box, each coin has a 50% chance of flipping. Coins that flip turn blue (decayed). The gold coins are your remaining undecayed parent material — count them and enter your count!

Tip: Click on blue (decayed) coins to number them as you count. Marks persist between shakes, so you can keep track of which ones already decayed!

Note: This simulation uses true randomness, so your results will vary each time — just like real radioactive decay!

🎲 Simulation
💡 Click blue coins to number them! Marks stay between shakes.
0
Shake #
0
Marked
Enter the number of gold coins you counted
📈 Decay Curve

Data Log

Shake 0: 100
📚 Pre-Lab Questions

Read the lab introduction, then answer these questions before starting the simulation.

1 Using Models: What is the advantage of creating a simple model of radioactive decay?
2 Inferring: Why is a penny useful for representing a radioactive isotope?
3 Using Models: What represents the parent atoms in this activity? What represents the daughter atoms?
4 Predicting: How will the abundance of the heads-up and tails-up pennies change over time during this activity?
5 Contrasting: Identify three ways in which this model differs from the actual process of radioactive decay.
📝 Analysis Questions

Use your simulation data to answer the following questions. Your data is shown below for reference.

Your Simulation Data

Shake 0
100
1 What percentage of the original 100 coins remained after shake 1? After shake 2? After shake 3?

Remember: with 100 starting coins, the count equals the percentage!

2 In terms of radioactive decay, what do the remaining gold coins after each shake represent?
3 In terms of radioactive decay, what does each shake of the box represent?
4 Compare your simulation results to the ideal decay curve. How do your results differ from or compare to actual constant radioactive decay? Why might there be differences?

Look at your data points compared to the dashed red line (ideal 50% decay curve).

5 After 4 shakes (half-lives), what is the ratio of parent material to daughter material?

Gold coins = parent, Blue coins = daughter. Express as parent:daughter

💡 Use the Half-Life Reference Chart below to help answer the following questions.
6 Suppose the radioactive isotope you are modeling has a half-life of 350 million years. How old is the sample if ¼ of the original material remains?

Think: How many half-lives does it take to get from 100% to 25%?

7 Some fossil bones contain ⅛ of their original amount of carbon-14. The half-life of C-14 is 5,730 years. How many half-lives have passed? How old are the bones?
📤 Export Your Lab Report

Download your complete lab report as a PDF. This includes your graph, data table, and all analysis answers.

Complete at least 5 shakes to enable export