how to control SMOOTHNESS via GUI slider?! It's not working...pls help!

hello world

I've been trying to use a GUI slider to control 'smoothness' of an object but It just doesn't work.

here's my latest atempt:

 using UnityEngine;
 using UnityEngine.UI;  
 using System.Collections;
 
 public class metalicslider : MonoBehaviour {
 public GameObject metasphere; // object that will be affected
 public Slider sldfind;
  Renderer sphrend;
 
 
 
     // Use this for initialization
     void Start () {
         sphrend = metasphere.GetComponent<Renderer>();
         sphrend.material.shader = Shader.Find ("Standard");
 
         
             }
 
 
 
 
     // Update is called once per frame
     void Update (){
         sphrend.material.EnableKeyword ("_SPECCGLOSSMAP");
         sphrend.material.SetFloat ("_SPECCGLOSSMAP", sldfind.value);
 
     }
 }
 

I checked the documentation, tried this one too, but no cookie

 using UnityEngine;
 using System.Collections;
 
 public class ExampleClass : MonoBehaviour {
     public Renderer rend;
     void Start() {
         rend = GetComponent<Renderer>();
         rend.material.shader = Shader.Find("Specular");
     }
     void Update() {
         float shininess = Mathf.PingPong(Time.time, 1.0F);
         rend.material.SetFloat("_Shininess", shininess);
     }
 }

please, help me!