Detect collision of a child object with tag

Hello everyone, I want to detect the collision of a child object, for example I have a player object(parent) and contains the child objects which are the parts of the player(head,arms,legs...). I want to detect for example if my spear hits the head object which is child object and if does hit the head my player will die. I try to do the obvious technic:

Code (CSharp):

1. if(collision.gameObject.tag == "Head")
2.         {
3.             Debug.Log("Enemy head");
4.             FindObjectOfType<EnemyAI>().playerHealth -= 100;
5.         }
6.         else
7.         {
8.             FindObjectOfType<EnemyAI>().playerHealth -= 50;
9.         }

But it doesn't detect the tag.
BTW the script is attached to the spear object.

 

Make sure both spear and the head have a rigidbody component on it, even with "gravity = off" and "kinematic = on" , anddand try to write this "collision.transform.tag == Head" instead... (Or use the "CompareTag" that is better). if this doesn't work make the head a trigger and use the "void OnTriggerEnter()"

Hope this help.

 

make sure that all your child's game objects have the tag that you are searching for and not the parent game object