Noon shadows on the Equinox

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This sounds like a fun project (originally written for schools):
You and your students are invited to participate in an annual daytime astronomy project titled - Noon Shadows on the Equinox. The fall (autumnal) equinox will occur this year at 12:03 A.M. EDT (04:03 Universal Time) on Saturday, September 23rd. At that moment, the Sun will cross the celestial equator, and it will mark the official start of autumn in the Northern Hemisphere and spring in the Southern Hemisphere. The activity should be conducted during the school day on Friday, September 22nd. During this outdoor lesson, your students will be measuring the length of a shadow cast by an upright meter stick. The time of the shortest shadow length measured all day will mark solar noon - the Sun's exact midday position in the sky. By calculating the angle between the tip of the shadow and the vertical meter stick at solar noon, your students should be able to determine their own degrees of north or south latitude (but let them discover this neat bit of astronomical geometry). All data submitted will be posted for viewing. Schools from as far away as Puerto Rico and Hawaii have participated in the past.