Each year the Harvard School of Engineering and Applied Sciences offers a family-oriented Holiday Lecture — an engaging and fun forum for ages 7 and up, modeled after the Royal Institution Christmas Lectures of 100 years ago in London.  This year’s Holiday Lecture — A Grain of Salt: Isn’t It Ionic? — will be held 10AM-11AM on Saturday, December 5 in Lecture Hall B of Harvard’s Science Center (map).   It’s free and open to the public.  Pre-register online now for guaranteed seating.  See videos of previous years’ lectures here.