Countdown to Mystery Class: Four Months to Go!

Autumn officially began in the Northern Hemisphere last week, and days are getting shorter. This month, explore what causes day and night.

Mystery Class begins January 28, 2013. Watch for monthly "Countdown to Mystery Class" messages to help you and your students get ready for the challenge.




Image of the Month

Follow the Sun
Day and Night
Image: A Clevenger

How Can I Prepare Students? Track Changes in Day Length

Report your October 1st photoperiod:

  • Look up your data for October 1.
  • Report data (select "daylight").
  • View data on photoperiod map.


Report to the Map!

Slideshow: What Makes Day and Night?

Observe, Wonder, and Predict
Observe images of the Earth from space. See how sunlight strikes the Earth over the course of a day. Use the slideshow and activities to explore the 24-hour cycle of changes.

What Makes Day and Night?
Just for Teachers: Helpful Links
The Next Countdown to Mystery Class will be posted November 1, 2012.