How is the friendliest way of getting a pet snake to smell your hand without fearing or triggering any responses to it? (ex. like having my hand above the ground or low to which they can see it.)

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the dependent variable in galileo's experiment?