When you learn a sport learn it for real. This is useful for people who practice self defense from staged events like movies, must be alert because these are framed just for the movie and for entertainment purposes and might not be useful in real life. Traditional martial arts are known to teach like a real life situation. This method of teaching is very useful because children might need to defend themselves anytime. Remember that self defense for children are not the same as self defense for adults. Adults need extra force to over come the strength of the enemy whereas; children need to know which the weakest points on the enemy is. Then they can attack the enemy in those parts.
If you have ever been to a martial arts class or a self defense center, you might have noticed that techniques are different for people of different age. When it is time to leave your children to do things on their own, the defense mechanism is a part of that too. When your child hangs out with friends, there is a chance that an assailant might grab your child and go in a few seconds. You might need to introduce your kid to some defense weapons.
Some of the defense materials available in the market are kubotan, teasers, knives etc. Some weapons might be non lethal and you need special permission regarding their usage. The effects of some of these weapons are deadly and you do not need to use these all the time. Also knives should not be given to kids instead of a knife, a pepper spray works well.