The Steve Spangler Science Color Changing Beads are a simple and fun way to teach the powerful effects of UV rays. This set includes approximately 250 beads. The ultra-violet sensitive pigment changes the beads from white to the assorted colors of blue, green, orange, purple, red, and yellow. This STEM activity is a fun opportunity for the kids whether it is a beautiful and sunny or gloomy and cloudy. These beads are reusable and will change over and over again without fading. The UV beads can even be turned into a fun science experiment by finding different types of medicine bottles and testing to see which one is the most effective in blocking the beads from the harmful effects of the UV rays. COLORS INCLUDED: Red, Purple, Yellow, Orange.