I absolutely love teaching moon phases and after 14 years, I feel like I've almost perfected the art of teaching this concept. I've created a lot of new things, come up with tips and tricks that will stick with my students, and created some pretty awesome hands-on activities for my students to be able to interact and experience the lunar cycle. And because I only use activities that give me 'a lot of bang for my buck,' I'm able to shorten the amount of time I need to teach the concept and students are mastering the material in less time than ever.
I begin on the first day with an engagement activity in which students receive a baggie full of moon phases and they are simply asked to place them in a logical sequence on their table. When they are done with the task, they raise their hand for me to come check it. Over 90% of the time, students will place the pictures in the correct sequence, but they will have the moon pictures laid out in a straight line. So I ask, "What comes after this last picture?" And they usually grab the first picture in the sequence and drag it to the end. Then I ask the exact same question again, followed by another card moving from the beginning of the sequence to the end AGAIN. So I ask, "Is there a better way you could lay these pictures out on your desk?" They very quickly realize that a circle is more appropriate because the moon phases are a never-ending cycle. There is no beginning and no end.
After this engagement activity, I begin the "Lunar Lollipop Investigation" in which each student gets to experience and discover for themselves what causes us to see various moon phases from earth and why the moon appears to be lit in the sky.