Mmmmmm - Science!

Year 9 Science

Michelle O'Brien

Classroom Teacher - Science

Students in Year 9 are currently learning about radioactivity in our science classes. 

Radioactive decay is the process by which an unstable atom, or radionuclide, releases energy and changes into a different atom. This process continues until the forces in the nucleus are balanced. 

Our class activity used M&M chocolates to model radioactive decay. This hands-on learning helps students to understand the process of radioactive decay and how it relates to the half-life of radioisotopes. 

In this exercise, our M&Ms represented radioactive atoms.

Student teams were tasked to 

1. tip all of their M&Ms out of a cup and onto their desk
2.  inspect how each M&M had landed on the desk
3. record their findings

• If the M&M had landed 'm-side up' it was deemed to have 'decayed' and were then discarded (or in non-scientific terms, eaten!)
• If the M&M had landed 'm-side down' it was deemed not to have 'decayed', so were returned to the cup.  Needless to say, students were fervently hoping for 'decayed' M&Ms!

The teams repeated this tip and examine process until their entire allocation of M&M had disappeared.

With every shake and tip of the cup,  there was a 50/50 chance that each M&M would land either m-side up or m-side down, so with each successive tip the number of remaining M&Ms gradually decreased to zero. 

So, using this activity students could mimic how the radioactivity of a substance decays towards zero if enough time passes!

The students also had a chance to practice their maths skills in this activity, graphing their results to generate a radioactive decay curve.