PlayParticle.cs

using UnityEngine;
using System.Collections;

public class PlayParticle: MonoBehaviour {

    public ParticleSystem myEffect;
	
	void OnTriggerEnter(Collider col)
    {
        if (col.CompareTag("projectile"))
        {
			Debug.Log ("playparticle!!");
            myEffect.Play();
        }
    }
}