What would be a fun Science activity that introduced 6 to 7 year olds to the basic concepts of light?

Flash Lights and mirrors. Have the kids try and figure out how to arrange the mirrors to reflect the light from a set starting point to a set end point. Make it a simple zig zag pattern, possibly include the ceiling and floor to enforce the idea that light reflects off of angles. They can get up, move, point the flash light in different directions and you can get by with as little as only 2 mirrors if you move the first one as they correctly find the spot. But I feel showing them the full pattern from start to finish will help make them feel like they "won" the game.