One difference is confidentiality. Adult arrest and conviction records are public documents. Juvenile records, on the other hand, are sealed to the public. The original idea behind keeping juvenile confidentiality was that a stupid mistake made as a child shouldn't haunt the person for his or her entire life. It was thought that children, still in the formative stages of development, could become productive adults if put on the proper path.
A second difference is punishment. Juvenile punishment tends to be far less harsh than the punishment of adults for the same crime. For example, juveniles can be sentenced to juvenile homes rather than to prison. In fact, juvenile sentencing tends to focus more on rehabilitation than punishment.
A third difference is procedural. Juvenile hearings tend to be far less formal than adult trials.
Juvenile courts don't just handle criminal matters; they also handle cases involving juveniles who need help from the state, such as those who have been abused, and they handle what are called status offenses, which most commonly involve truants and runaways. Within the juvenile court system, juvenile crimes are handled more formally than the other two types of cases.
Much of the traditional approach to juvenile justice has come under attack in recent years, as younger and younger children have committed more and more violent crimes. Society has not been as willing as in past years to treat these juvenile acts leniently. The juvenile rule that children age 15 to 17 can be tried as adults under certain circumstances has been invoked far more often in recent years.
Federal law. Although juvenile law is mostly based on state law, there are federal juvenile laws, which address federal crimes committed by those under 18. Because there are relatively few federal crimes, federal law doesn't play a large role in the juvenile system.
Procedure. Juveniles who have been arrested are supposed to be detained separately from adults. In reality, however, juveniles are often detained in the same facility as adults. Many of the same protections afforded adult defendants are given to juveniles. For example, juveniles have the right to know the nature of the charges against him or her, they have the right to an attorney or have one appointed if they cannot afford an attorney, and the standard of proof - beyond a reasonable doubt - is the same. One key difference is that juveniles do not have the right to a jury trial.
Punishment. Juveniles who are not being tried as adults are typically given some form of probation, particularly first-time offenders. The harshest sentence that can be given is to be sent to a juvenile detention center. Juvenile detention centers are similar to prisons, except that they house only juveniles. In some cases, juveniles can be removed from their homes and sent to foster homes. If the juvenile is given some form of probation, he or she will be assigned to a probation officer, who will monitor the juvenile's progress. Repeat offenders, of course, are treated more harshly than first-time offenders.