i press space and the player isnot jumping what is wrong? details in description

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class playerController : MonoBehaviour {

 public float speed;
 public float jumpHeight;
 public Rigidbody rigid;

 private Vector3 direction;

 // Use this for initialization
 void Start () {

 }

 // Update is called once per frame
 void Update () {
     direction = new Vector3 (Input.GetAxis ("Horizontal"), 0, Input.GetAxis ("Vertical"));
     if (Input.GetButtonDown ("jump")) {
         rigid.AddForce (Vector3.up * jumpHeight, ForceMode.VelocityChange);
     }
 }

 private void FixedUpdate ()
 {
     rigid.MovePosition(transform.position + direction * speed * Time.fixedDeltaTime);
 }

}