The concept of air resistance is related to Newton's second law of motion, which describes acceleration and force. Air resistance is a significant factor in how fast an object falls, according to this law.
The example of the "elephant and the feather" is often used in classrooms to demonstrate how Newton's law applies to air resistance. If dropped in a vacuum, the elephant and the feather fall at the same rate. Objects falling in Earth's environment, however, are acted upon by gravity and air resistance, which causes the elephant and feather to fall at very different rates. In the absence of only air resistance, they would hit the ground at the same time.