Copyright law is complicated enough within the United States, but it is important to remember that when your child is in IB, you are dealing with an international organization and are subject to foreign laws and unfamiliar conventions. You might want to look this over before its time for your child to turn in his or her extended essay.
If you have produced something of exceptional quality or individuality—perhaps a design for a new product or a musical composition or a computer program—you might like to make use of this commercially, or you may wish to send an extended essay for publication. In these cases, you may not want the IB to reproduce your work for publication. You may therefore wish to withdraw the licence to the IB to use this piece of work and claim exclusive copyright. This is not a right to claim frivolously—and you should note that this is unlikely to apply to an examination script. First discuss with your teacher any claim you are thinking about, and he or she will, if really necessary, help you complete and send in the relevant IB form with your work. Watch out for the deadline for this.