Capturing the Energy of the Sun with UV Beads

My class has been working on machines and energy, so we read a great book called Energy – Make Things Happen.  It’s a great book that explains potential (stored) and kinetic (moving) energy in a very kid friendly way.  It also talks about how all energy comes from the sun.  This concept, however confused my kids a little and one student kept asking how the sun was touching the grass in order to make it grow.  My best explanations weren’t helping, and then I realized that I had a tool to show it to him.  Stuck on a shelf in my classroom – left over from one of my son’s birthday parties – were some UV beads.  These handy little beads turn color only when hit by the sun’s rays. 

So, as an impromptu add in to my lesson (don’t you love when that happens – throw the lesson plans right out the door!) we made necklaces with the UV beads.  Indoors, all of the beads are white and don’t look like anything special.

Then, we headed outdoors, on a rare cloudly day.  (We’re in Morocco, where the sun shines almost every day.)  Even with the clouds, the minute we were outside in view of the UV rays, the beads began to change color.  The kids were so excited, and we were able to have a discussion on how the sun’s light can travel through air, transferring it’s energy to the grass, which then transferred it to a dinosaur, which died and transferred it to a fossil fuel, which we then transfer into energy to move our car.  The sun starts all energy! 

How have you used UV beads in your classroom?