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Hands-on physics

Sunday morning, 10 a.m. While most teachers are at home enjoying their weekend, several hundred have come to Chicago to attend the conference of the American Association of Physics Teachers, which coincides with the AAAS meeting. I'm sitting in a meeting room with about 40 teachers who have huddled in groups of two to four to solve a tricky particle physics puzzle to build protons and other particles made of quarks.

"It is really neat to see how engaged you are," says Marge Bardeen, who presents this AAPT session. "Imagine how your students would get engaged in this activity."

Bardeen is the head of the Fermilab Education Office. Teachers regularly come to Fermilab to develop new classroom activities and experiments. Here at the AAPT/AAAS conference, Bardeen shares their results with other teachers.

A good example is a low-cost particle detector that teachers and students can use to detect cosmic rays, the stream of invisible particles that constantly bombard earth. The detector allows students to record the particles and make scientific measurements, which they then compare with results obtained by other students at different locations.

"One student even observed solar flares," said Bardeen. "He then communicated with a student in Australia to confirm his observation."

Other examples include the measurement of radioactive decay in pennies. The coins mostly consist of copper, and the challenge is to find out whether all coins have the same content. Measuring the radioactivity of many coins made in the same year, the students discover that pennies made before 1982 cause different peaks in their charts than those made post 1982. The composition of the material used for pennies changed in 1982. The United States switched the penny's core to zinc and coated it with copper.

Another teacher developed a teaching unit that allows students to determine the mass of the top quark. Starting with the tracks of particles recorded by the collider experiments at Fermilab, students measure the length of particle tracks, measure the angles between pairs of tracks and then use simple vector addition to calculate the mass of the top quark.

All activities are geared toward physics master classes, which science teachers usually offer as extracurricular sessions at their schools. To find out more about these activities and programs, visit the Web pages of the Fermilab Education Office.