Designed by California Physics Teacher Dean Baird, this versatile system allows students to see and control light beams. Scattering agent added to water in the plastic tank make laser beams visible. Students easily control observations involving simple refraction and total internal reflection. Includes Laser Viewing Tank, multi-line diffraction grating, acrylic stirring rod, removable opaque background screen and teacher's guide. 18"W x 6"H. Demonstrate gradual (curving) refraction with sugar!, Split a single laser beam with the diffraction grating. Show why daytime skies are blue while sunrise and sunset skies are red. The ultimate laser light workstation, Safe laser viewing