Students will be able to explain how scientists determine the ages of rocks using radioactive decay.

Complex and microscopic structures and systems can be visualized, modeled, and used to describe phenomena.

5 minutes

To introduce the idea of radioactive decay and carbon dating, I play a video clip from Nova "Hunting the Elements". As the video comes to an end, I pose the question, *"Why is Carbon-14 useful to determine the age of organic remains?"*

35 minutes

I tell the students that they will now become archaeologists as they play with the PhET simulation "Radioactive Dating Game". I ask the students to divide themselves into partners, and request that one partner to get a computer, while the second partner gets the record sheet they will use. Although students could work through the simulation individually, I prefer partnerwork to foster discussion among students, encouraging scientific discourse (**SP7**).

In this video I walk you through using the simulation.

As the students work on the simulation they are visualizing how stability and change in natural or designed systems can be constructed by examining the changes over time (**CCC Stability and Change**), as well as analyzing and interpreting data **(SP4**). here are some examples of student work (SW1, SW2).

5 minutes

To close this lesson I ask that students write, on Edmodo, what was the most interesting thing they learned in today's lesson. The review of this responses allows me to gauge not only how the lesson went, but also how the simulation engage/did not engage the students. Here's a sample of what they answered.