This document discusses physical development during infancy. It covers growth in height and weight from birth to age 1, with birthweight typically tripling. Four principles of physical growth are described: cephalocaudal, proximodistal, hierarchical integration, and independence of systems. Motor development milestones from rolling over to walking and jumping are provided, along with a chart showing fine motor skill development from ages 3 to 33 months. The development of the senses like vision, hearing, smell, taste and touch are also summarized.