Alpha, Beta, Gamma, Oh My!
by Tom Kelley
High School Science Chair
In the first week of January every year, the students in some High School Science classes have a unique opportunity to do a sampling of about 20 different experiments relating to nuclear physics. The experiments range from a measurement of the penetrating ability of alpha and beta particles in various materials (wood, aluminum, plastic, lead, etc) to measuring the half-life of a Barium isotope extracted from a Cesium source. These are a multitude of experiences that are never available in a regular high school laboratory setting because the materials and instruments are just too expensive to purchase and maintain.
This is all made possible through a connection made years ago with the Faculteit Betawetenschappen at the Universiteit Utrecht. Rob van Rijn is one of three specialists from the program who travel around to many Dutch schools with a car load of specially constructed boxes containing the experiments. The Dutch government supports this program for the schools with only a minimal 50 euro cost to ASH. In a matter of 20 minutes, Rob turns the physics lab into a complete nuclear physics experimental lab with all 20 experiments up and running. Students in AP Physics, AP Chemistry, IB HL Physics, Physics II and Chemistry II all have units on nuclear physics and so these experiments represent a rare chance to do hands on work with these concepts. All day the students from these classes come in to work with the experiments with their teacher and Rob as their guides.
At first, students may be a bit nervous about the “danger” of doing this work, but as Rob explains, doing an hour’s worth of experiments is about the same total dose of ionizing radiation exposure as 10 minutes in a trans-oceanic flight. He carefully explains the safety aspects first, and then we set the students loose to do as many different investigations as they can in the 90-minute period. At the end of the period, Rob does a demonstration of X-rays using a leaded glass viewing box and then the crowning moment, (at least for me!), is the Wilson Cloud Chamber in which students get to see the vapor trails of alpha and beta particles from a source as well as the occasional background radiation trail.
It was a great day and we will look forward to doing it again next year.