First, ask the kids if they know how a rainbow is made. (When I asked my Primary, JR didn't have a clue. They had some funny answers, but didn't really know. SR got really close to knowing. They had some trouble defining reflection/refraction, but we worked it out.)
Second, tell them there's an equation to make a rainbow. Put up the blue signs (well, mine are blue, yours can be whatever you want) and say "You need sun... plus rain.... to make a rainbow!" (I taped them to the chalkboard and drew a plus sign after "sun" and an equal sign after "rain"). Go however in-depth you feel appropriate on how refraction works and whatnot. It's not a science lesson, so I gave it a proper skim-over.
Then tell the kids (I'm paraphrasing what I said)...
"Aren't rainbows beautiful? I sure think so! Did you know that you can have something very beautiful -even more beautiful than a rainbow?! Yes, you can! Here, let me show you. To get something even more beautiful than a rainbow you need sun.... OH! but not this kind of sun! Nope. You need THIS kind of Son! (flip over sun/Son). Who knows who this is? Yes, that's right! It's Jesus! He is Heavenly Father's Son! And let's see.... you also need water. But not rain! Nope. (flip over rain/baptism). You need the waters of Baptism to have something very beautiful. And when you have these things you will get something very beautiful... (flip over last one)... Yes! You can have eternal life! Eternal life and the chance to live with Heavenly Father again is a very beautiful gift that we are given. We can be baptized and we can keep Heavenly Father's commandments so that we can live with him again."
I then read this quote from Sister Elaine Dalton's (YW General President) talk, "Now is the time to Arise Forth and Shine", April 2012 General Conference. I told the children who she was and then I read --->
"Several weeks ago I stood in the celestial room of the Reno Nevada Temple. The light streaming into that room was brilliant and was made even more so by the crystal chandelier, which reflected the light on its many carved facets into rainbows of illumination everywhere. It took my breath away as I realized that the Savior is “the light and the life of the world,” that it is His light we must hold up and reflect. We are the tiny crystals that reflect His light, and in order to do that, we must be clean and free from the dust of the world."
Lastly, I segued into our activity (which was magic color cups) with something like "now will you help me make the colors of the rainbow with the magic color cups I brought today? The cups will change colors and tell us what songs to sing.... and that led right into our Rainbow Review.)
*I combined ideas from the LDS Choristers Facebook Group (thanks Cheri W and Jessica S).
- I could see the enlightenment on their faces. Great lesson.