Thursday, September 1, 2011

How a ‘half-life’ can impact a whole life…

In the aftermath of unexpected earthquakes in unlikely locales, in anticipation of the already interesting hurricane season, and in preparation for 10th anniversary remembrances of September 11, 2001, we start these content-focused blogs with the timely EPA issue of Emergencies. Addressing ‘uncertainty’ within the context of Environmental Science, we can empower students to be prepared for and respond more readily to natural disasters, hazardous spills, and the unexpected by helping them understand the basics. These future decision-makers may be able to safeguard against the rapid changes happening on a global scale and certainly cope better with the consequences with an understanding of the complete process.

Think back to last month's Balancing Acts activity... often, seemingly unrelated subjects are tightly linked. For example, the nuclear emergency in Japan that most of us watched in real-time this spring was caused by a tsunami. In the event of a nuclear disaster, calculating the half-life of radioactive contamination will determine when an area is safe. We tend to dismiss radioactivity as a natural phenomenon; many people think that it only occurs in nuclear power plants or as the result of a nuclear accident. Radioactive rays are emitted when a radioactive atom decays. Nuclear radiation can be a good thing depending on how it is released. Nuclear medicine is a specialty that relies on the process of radioactive decay in the diagnosis and treatment of disease, for example.

Students often associate ‘half-life’ with nuclear power, but do not understand always that it equally applies to other naturally radioactive elements - nor do they associate the dangers of the long-term ramifications of radioactive materials disposal with respect to nuclear waste management. Best used as a formative assessment, A Dating Game helps learners internalize what a ‘half-life’ really represents with a simple, fun, and safe activity that stimulates discussion. Click here to download the assignment details!

HippoCampus Connections: The ability to transfer knowledge across situations is a sure sign of understanding and mastery. The Coral Age Dating activity in NOAA: Seamounts is a real-life simulation of the concept presented to actually define and apply isotopic age dating of corals.

Because some students may not comprehend the drastic effects of natural disasters, the before and after images in NOAA: Hurricanes can help them appreciate the powers at play. And, in the case of natural disasters, we can show students a proactive aspect as early warning systems have been implemented to evacuate threatened areas, for example see the Tsunami Warning System in NOAA: Ocean Waves.

Instructor Notes: As those of us who replay the vivid images of the 2001 terrorist attacks in our mind’s eye realize how ubiquitous communication networks can have equally positive and negative impacts that do not cancel out, but accumulate over time. Therefore, it’s important to identify, acknowledge, and possibly discuss the differences in perspectives among the many stakeholders who influence your students. Remember that most of today’s high school students were likely just 3-8 years old way back in 2001! I’m excited about the potential of leveraging new technologies for the betterment of the environment and its inhabitants – come whatever may… Challenge your students to make a difference right now! What Apps for the Environment might they propose?


  1. Check out the PhET Radioactive Dating Game activity in the new (beta) HippoCampus Earth Science collection too! You can play a game that tests your ability to match the percentage of the dating element that remains to the age of the object.

    Also be sure to access many other teaching ideas for using it at the UC-Boulder site (

  2. In case it's helpful, the new HippoCampus site (and PhET's Radioactive Dating Game simulation) is available at Everyone is welcome to come explore.