Cross-posted on the Burlington Science Center blog.
There is plenty to celebrate the week before holiday break, but among the many religious traditions don’t forget to take pause on December 22nd to celebrate a very special day in Earth’s orbit with your students or children, the winter solstice!
The winter solstice is the shortest day of the year for the northern hemisphere (top half) and marks the start of what we consider winter. For residents of Burlington, the sun will shine for only 9 hours and 5 minutes. Amazingly the day is even shorter the further north you travel, with anyone unfortunate enough to be above the Arctic Circle receiving no sunlight whatsoever! The length of our day is affected not by our distance from the sun but the tilt of Earth’s axis. The axis is an imaginary line running from Earth’s north pole to its south pole that spins or rotates around. Unlike a top that spins standing straight up, Earth rotates slightly sideways at a 23.5 degree angle. This is roughly the angle one might make to form a peace sign with their index and middle finger.
During the Winter Solstice the earth’s north pole is pointed away from the sun, causing the northern hemisphere to receive fewer sunlight hours and less solar energy from the sun. Meanwhile, the south pole and southern hemisphere of the Earth is pointed directly toward the sun and receives their longest day of the year! For southern hemisphere residents, December 22nd is the summer solstice! Because Earth points in one direction over the course of an entire orbit (revolution), we in Burlington point away from the sun in the winter months, but point toward the sun during the summer months. Besides sharing some of the information above with your students or children, consider taking time during the final day or two of the 2011 school calendar to do one or more of these fun solstice activities.
Make a Sundial Class Activity – Produced by the Science Center and specifically designed for Burlington residents, this is a science activity where each student creates and uses their own sundial to tell time using the sun. Students will recognize how their shadows change in length and location over the course of a day. The link connects to a student worksheet and sundial template. Appropriate for grades 3-5. Some cutting is required. Grades K-2 may adapt for younger grades by having kids trace their shadows at different times of the day and answer similar questions posted on the student worksheet.
Computer Simulations and Animations:
Earth in Motion: Seasons – Follow Max around the world and learn about how the tilt of Earth and one’s location on Earth influences the seasons (and how Max should best plan his trip!) via Teacher’s Domain.
Seasons Interactive Animation – Best used as a class demonstration on an interactive whiteboard. Allows students to mark and predict where Earth will be in its orbit around the sun during each month. Courtesy of Freezeray.
There Goes the Sun – For more information on the historical perspective of the Winter Solstice and how ancient civilizations commemorated the day, check out this New York Times OpEd piece written by Richard Cohen. Note: most of the material here is not suited for elementary students but is a curious peek into human past traditions!