The freon in air conditioners (home or car) and refrigerators changes from gas to a liquid and back to a gas, which then repeats. This is a physical change because the freon does not change its chemical makeup, just its state (liquid versus gas). A physical change is easily reversible. So the process can repeat and continue and keep us and our food cool.
The human hand is at the end of the arm and is composed of five digits. Index: second finger of the hand, next to the thumb. Second finger: middle finger of the hand. Third finger: second finger from the outside of the hand. Fourth finger: small finger closest to the outside of the hand. Distal phalanx: bone at the end of a finger. Middle phalanx: small, middle bone of a finger.
There are three bones in each finger called the proximal phalanx, the middle phalanx and the distal phalanx. Each finger has three joints. The first joint is where the finger joins the hand.This joint is where the bones that form the palm of the hand, the metacarpals, join with the first bone of the finger, called the proximal phalanx.The second joint is the proximal interphalangeal joint, sometimes called the PIP joint for short.he first joint is where the finger joins the hand. This joint is where the bones that form the palm of the hand, the metacarpals, join with the first bone of the finger, called the proximal phalanx.