SCHOOL years are a time of unusual growth and change in children. They are soaking up huge amounts of information and experiences and are developing individual personalities. They begin these years by learning through hands-on, concrete experiences, and they end them by becoming able to do abstract thinking. Children grow at their own pace in all areas of development, and they often grow in spurts. However, the following milestones are generally accepted as normal for 11-to 12-year-olds. Physically, they are full of energy, look more adult than they did at 10, and have good co-ordination and strength. Menstruation in girls may begin, the individual differences between sexes is more apparent, and children show a growing interest in sexuality. Mentally, they are able to think and talk about morals and social problems. They usually like stories of adventure and mystery. They are impressed with their own knowledge, but are able to see others' points of view, even if they don't wish to admit it. They understand reproduction and the life cycle, and are interested in the reasons for health and hygiene practices. They are often critical and reflective as well as very observant. Emotionally, they may have mood swings, they often want more freedom and independence than is allowed, and they may become argumentative and rebellious about this or about routines and chores, which they have decided to dislike. Socially, boys tease girls and girls tease boys, there is lots of hero worship, and children want a best friend. They want to feel they belong to a group. They really love to talk to friends on the telephone, and they like to earn their own money. They like projects, sports, and music.