Less than 6 hours of sleep reduces the child's intellectual level of 20-30%, scientists have calculated. Their conclusion is that kids have to go to bed on time and not hang with the adults at the table or watching TV. Especially useful is a small siesta.
According to the American David Folks what the child sees in the dream depends on the child's age. According to his studies of 3-4 year old kids they dream most often of animals or playing in their usual place. 5-6 year olds dream of relatives and acquaintances.
In 9-12 year olds they dream of the home, the street or of school. Girls of this age often have a pleasant, happy dreams, and the boys argue and fight.