One of the harder ideas to grasp in fusion is that nuclei, which, because of their electric
charge, strongly repel at long range (compared to the size of a nucleus), can strongly
attract at short range. This activity allows students to explore a similar situation in which
the magnetic interaction provides the repulsion (similar to the electric interaction within
the nucleus) and Velcro provides an attractive force at short range (similar to the nuclear
strong interaction).
This activity can be used directly in a unit on plasmas and the solar system, or at any time
when plasmas, nuclear science, or fusion are being discussed. Students also have the
opportunity to review basic features of magnetic poles.
You may wish to use this activity in conjunction with another cpep inquiry based
activity, Testing a Physical Model. It is designed to help students visualize the kinds of
reactions that take place in fusion and what variables they depend upon by simulating a
nuclear fusion reaction within a confinement vessel. Both activities introduce the
students to the idea of using models as a valuable way to understand physical
