Sphere is not using OnCollisionEnter/OnTriggerEnter/OnCollisionStay/OnTriggerStay functions

Hello,

I have recently tried to start a new game in unity, and I made a playground scene to test the mechanics and all. Currently, I have a ball that stays on the ground, can move, and jump, but I want to restrict the ball from jumping more than once until it lands back on the ground. However, I cannot get the ball to detect the ground with this code (attached to the ball):

 using UnityEngine;
 using System.Collections;
 
 public class BallController : MonoBehaviour {
 
     public float ballSpeed;
     public float jump;
     public float maxAngVel;
     public float jumpCount = 0;
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () {
         float xSpeed = Input.GetAxis ("Horizontal");
         float ySpeed = Input.GetAxis ("Vertical");
 
 
         Rigidbody body = GetComponent<Rigidbody> ();
 
 
         body.AddTorque (new Vector3(xSpeed, 0, ySpeed) * ballSpeed * Time.deltaTime);
         body.maxAngularVelocity = maxAngVel;
 
         if (Input.GetKeyDown (KeyCode.Space) && jumpCount == 0) {
             body.AddForce (new Vector3 (0, jump, 0));
             jumpCount = 1;
         }
             
     
     }
         
 
 
     void onCollisionEnter (Collision col){
         Debug.Log ("test");
         if (col.gameObject.tag == "ground") {
             Debug.Log ("Touching the ground");
             jumpCount = 0;
 
         }
     }
         
 }
 

Here is how my ball object is set up:

it has a child empty game object, with this currently on it:

The empty child is the actual sphere collider, while the collider on the parent is a trigger that has a radius a slight bit bigger than the child, for when I tried to use OnTriggerEnter/OnTriggerStay functions.

I have tried all 4 functions I mentioned in the title with no results. What am I doing wrong? [1]: /storage/temp/92155-unity1.png [2]: /storage/temp/92156-unity2.png