Moon Phase Demo

This comes to me from Tiffany E. Smith, Science Teacher at Stroudsburg Junior High School, PA who attended one of my workshops at the 2003 NSTA Convention in Philly. It's quite cool! Here it is in her own words.

When I was student teaching last year I was struggling to figure out a way to teach phases of the moon, because I feel it is something difficult to teach and it is also easy to misunderstand. I got this idea from a professor at Bloomsburg University, unfortunately I do not know his name, I didn't have him for class, but it is wonderful.

  1. Take a large piece of cardboard and cut it into a square. Mine is probably 1m x 1m or a bit larger.
  2. Spray paint it black on one side.
  3. Cut a circle in the center of the cardboard large enough for a student to put his/her head through.
  4. Get 8 (or more if wanted) ping pong balls. Using a black sharpie marker, color one half of each ball black.
  5. Ok here is where it is difficult to explain. Using very strong glue (I used Duco cement), glue one ping pong ball a determined distance from the center of the cardboard. Ok let me try to explain this better. Look at your piece of cardboard with the hole in the center as if it were a compass. Go north of the hole whatever distance you decide (we'll say 16 inches) and glue the ping pong ball so that the black side is facing east and the white side is facing west. Do the same directly south, east, and west of the hole in the center of the cardboard, at the same distance (16 inches). Be sure that the black sides of the ping pong balls are all facing the same direction. Now, you can do this at your NE, SE, SW, and NW directions as well. When the glue dries, place the board over your head, have someone hold it in place for you, and you rotate. Whichever side the white half of the balls face is where the sun is. Your head is the earth. When you rotate, you are seeing the phases of the moon. Common mistake is to have the people holding the board to move, but this is wrong. You just rotate. I think this thing is great!! It makes the phases of the moon so easy to teach because they can actually experience the position of the earth, sun, and moon in a 3D way rather than 2D how most textbooks try to teach it. The prof. I got the idea from did not use glue, he used tiny screws to hold the ping pong balls in place but I'm not that crafty. A great place to get cardboard that large is from a store that sells refrigerators, washers, and dryers.
I have some pictures on the web of it. The website itself is very old, was never really complete, and hasn't been updated but the pictures are there. Hopefully the website will still be there when you attempt to view it, Bloomsburg threatens to get rid of your website after you graduate so I'm hoping that won't happen!!

Tiffany E. Smith
Science Teacher
Stroudsburg Junior High School

Thanks, Tiffany! I've included a couple of the pictures Tiffany had online just in case Bloomsburg deletes the site...

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