Definition of Physical Development

Physical development is the development of a child's mobility, thought processes and sexual characteristics. At birth, boys and girls develop at roughly the same rate. As children get older, the process becomes different for boys and girls.

• By the end of their first year, most babies can eat solids.

Newborns

• Most healthy newborn babies weigh between five and eight pounds. Babies' digestive systems cannot handle solid food at this point, so they derive nutrients from liquids given to them by their parents.

Toddlers

• By the end of the first year, babies can eat solid food and get around by crawling or walking. This is a period of accelerated growth for the child, and will last into early childhood.

Adolescents

• Children keep growing steadily throughout adolescence, until they become teenagers. During their teenage years, they will hit puberty, when secondary sexual characteristics start to appear.

Puberty in Females

• During puberty, girls' menstrual cycle begins, and their breasts get bigger. Growth in girls accelerates during puberty, according to Biology Online.

Puberty in Males

• Testosterone production causes a growth spurt in boys during puberty. Boys grow more body hair during puberty, and their voices deepen.