MR / Schenectady, NY.Yates Arts-in-Education Magnet School (urban elementary school) .Grade 4.Science mentor demonstrates the effect of the extreme cold of liquid nitrogen (generally about -196 degrees Celsius) on a geranium leaf in classroom experiment. Leaf is immersed in cup of liquid nitrogen and then cracks into pieces as it is slapped against the table. Mentor (materials scientist at research center, full-time working mom) volunteers weekly to demonstrate and explain scientific concepts..MR: g4m Lat5.© Ellen B. Senisi