Experiment with light and vision, sound, and hearing.
Our eyes and ears respond to light and sound waves, but these are just the first steps in perceiving the world. Playing with light and sound is the best way to learn how they work. Investigating real phenomena can also give you a deeper understanding of the scientific process.
With the rope hanging down, the left and right sides of the board appear identical. Lifting the rope shows the dramatic difference that your eyes missed—and continue to miss, as soon as you let the rope fall again.