Distance and Parallax

Extend your arm out in front of you; position your thumb as though you are giving the thumbs up. Point your thumb at an object in your house, outside, a friend, family member, or any object will work. Once you have found your object and your thumb is pointed at it, close one eye, then open and close the other eye. What do you notice? What happens to the object? Does the same change occur if your arm is not fully extended? Change the distance that your thumb is from your eyes.