Radioactivity is a topic in chemistry that can be difficult to teach if you are looking for a hands-on, data-driven approach. Safety and cost concerns often prevent students from having an inquiry-based experience with the topic. Two years ago, I was awarded an ACS Hach grant to purchase Vernier radiation detectors, radioactive samples from Flinn Scientific and a radioactive shielding kit also from Flinn. With these materials, I am able to give my students an authentic lab experience for them to determine there are three types of ionizing radiation without direct instruction. Prior to receiving the Hach grant, I found a great simulation that allowed my students to collect and analyze similar data with no equipment. Both activities are outlined below.
Radioactive decay, beta decay, alpha decay, gamma decay, radioactive shielding
1 class period
Flinn Scientific radioactive source kit (I have 2)
Flinn Scientific nuclear shielding super value kit
Vernier Radiation Monitors (1 per lab group)
Vernier interface with a digital port (Go!Links will not work)
Computers that can run flash
University of Colorado, Colorado Springs Simulation
Attached worksheet (optional)
While my students are walking into my classroom, I start the topic of radiation by turning on one of my radiation detectors and letting it beep as it picks up background radiation. It does not take long for students to start asking “what is that beeping noise?” I then show students the radiation detector and we discuss what they already know about radiation. I show students the different radioactive samples (I tape over the labels so they don't know what they are) and ask the students if they can think of any ways that we could determine if the samples are all the same or if they could be different. Students usually suggest comparing the counts/minute but soon find that those data are not reliable enough to make a conclusion. Once they see the pile of shielding materials on my desk, they get to the conclusion that you could try blocking the radiation with different materials.
From there, I set students off with the guiding question, “How many types of radiation are represented by these samples?”. Students then design their own experiments with the materials from the shielding kit as well as their own materials to determine if the 6 samples are the same or different. I do not have to give very much guidance at this point, sometimes just a nudge for students to select a wider range of materials. The alpha-emitter can be blocked by just a sheet of paper, the beta-emitter can be blocked by lead or even a thick piece of wood and the gamma-emitter can only be blocked by multiple layers of lead. Students usually get creative and use their notebooks, phones, hands, shoes and anything else they have lying around to answer the question.
When students finish collecting their data, I ask them to whiteboard their results and conclusion using the Claim-Evidence-Reasoning (CER) model. Students must state their claim at the top of the whiteboard (their answer to the guiding question), provide their data in an organized manner and provide an explanation as to how their data supports their claim.
The simulation is a little more guided than the lab activity though it does not have to be. The worksheet I attached will guide students through the data collection process. You could also show students how to use the simulation and then let them design their own experiment based on the same guiding question from the lab activity. They will simply have less options when they run their tests.
You could also have students present their simulation data with the same CER framework as the lab activity and ask the same extension questions. One of the benefits of the simulation is it gives you fun facts about the nuclides you are testing.
How many types of ionizing radiation are there?
Which type of emitted particle do you think is the most massive? Least massive?
Which type of radiation do you think would be the most harmful for humans to be exposed to?
Which type of radiation do you think would be the most harmful for humans if ingested?
If radon is an alpha-emitter, why are we concerned about it accumulating in basements?
Very little preparation is required for this lab aside from setting up your Vernier interfaces and setting out your materials.
Simulation activity adapted from University of Colorado, Colorado Springs Virtual Chemistry Laboratories
Please refer to the ACS Guidelines for Chemical Laboratory Safety in Secondary Schools (2016). Some additional information on these guidelines can be found in a Pick at ChemEd X.
RAMP: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies
Students that demonstrate understanding can develop models to illustrate the changes in the composition of the nucleus of the atom and the energy released during the processes of fission, fusion, and radioactive decay.
[Clarification Statement: Emphasis is on simple qualitative models, such as pictures or diagrams, and on the scale of energy released in nuclear processes relative to other kinds of transformations.] [Assessment Boundary: Assessment does not include quantitative calculation of energy released. Assessment is limited to alpha, beta, and gamma radioactive decays.]
*More information about this category of NGSS can be found at https://www.nextgenscience.org/sites/default/files/NGSS%20DCI%20Combined....