Actually, the primary factor in a baby’s ability to float is the ability to take air into the lungs. To maintain this access to air, the child must adjust his/her posture. The difference in positioning for an adult can be inches. For a baby, this adjustment is reduced to centimeters. If a child’s body posture is just a few centimeters off, it can make the difference between the face being submerged or the child having access to air.