Sara Infante listens intently and scribbles notes as her chemistry professor describes how to identify the masses and atomic numbers of two isotopes of carbon. When it's time to fill in a table showing that she understands the lecture so far, she…
This content is available exclusively to Chronicle subscribers
Already a subscriber?
Log in now
Not a subscriber yet?
Subscribe now for instant access to this article and thousands of others, data tables, and interactive charts — all available exclusively for Chronicle subscribers. Plus your subscription includes weekly print or digital delivery of The Chronicle and The Review and the Chronicle iPad® Edition.Subscribe Today