Your baby will be absolutely delighted in seeing the effect of turning a fan on and off. This is best experienced by tying ribbons around a stick or ruler and placing it in a planter full of soil or rocks. Place the stick and ribbons in front of a floor fan or where the breeze of a ceiling fan will make the ribbons flutter.
Have baby sitting up away from any ability to touch the fan or th ribbons. Watch his response to the ribbons flying in the breeze. After a minute a two turn off the fan and see if his reaction changes. Be sure to tell him when the fan is off and when it is on. If possible, let him see and hear that you are moving a switch and what that does to the ribbons. Cause and effect is an important brain development activity.