NEED HELP!!! How to explode my enemy ship? Need help with C# script

The idea is to throw a bomb and if it touches the Sphere collider in which my enemy ship is placed, it must destroy the enemy ship. So, first of all I must say that I’m new in C#, and with all that I know I tried to write a script to do so. I haven’t got any errors, though it does’t work. I’m sure it’s some logical mistake in the script and I would appreciate a lot if someone helped me with it. I need it for a project, and I’ve got a deadline…

so here goes the sript that I attached to the bomb:

float lifespan = 3.0f;
public GameObject explosionEffect;
public GameObject enemy;

void Update () {
    lifespan -= Time.deltaTime;
    if(lifespan <= 0)
    {
        Explode();
    }
}
void OnCollisionEnter(Collision collision)
{
    if (collision.gameObject.tag == "Enemy")
    {
        Explode();
        Destroy(enemy);
        Instantiate(explosionEffect, transform.position, Quaternion.identity);
    }
}
void Explode()
{
    Destroy(gameObject); 
}

And I also tried to attach a 'Explode" script to the enemy ship, yet it doesn’t work either…:
void Update () {

}
void OnCollisionEnter(Collision collision)
{
    if (collision.gameObject.tag == "Granade")
    {
        Destroy(gameObject);
        //Instantiate(explosionEffect, transform.position, Quaternion.identity);
    }
}

Note that the bomb has got the tag “Granade” and the enemy ship has got the tag “Enemy”.
Thanks a lot!

So you have the script attached to the bomb and than the first thing you do when colide is destroy the bomb whatever comes after won’t be executed, just change the order to:

Instantiate(explosionEffect, transform.position, Quaternion.identity);
Destroy(enemy);
Explode();