More than 4,100 students around the world took the Avogadro Exam this May, a test created and overseen by the University of Waterloo. Students demonstrate their knowledge of various chemistry principles and vie for prizes, which are awarded to those who score in the top five percent.

Only six U.S students made the cut this year, and four of them are students in Don Southard's AP Chemistry class. The HB students who achieved this impressive showing are seniors Gillian Rosen and Sarah Forcier, and juniors Tatini Mal-Sarkar and Ingrid Zippe.

The Avogadro exam is given to students who have completed no more than 100 hours of instruction in chemistry.