Health Bar Problem

I have been trying to implement a health bar that decreases when my player is damaged, though no matter which method I use, the image doesn’t scale down, it stays the same.

These are the tutorials I have tried and none have worked:

3. Unity 5 health bar tutorial - Values - YouTube

Unity 5 2D Platformer Tutorial - Part 13 - Player Health UI - YouTube

This is the current code I am using:

using UnityEngine;
    using System.Collections;
    public class PlayerHealth : MonoBehaviour {
    
    	public float Health = 100f;
    	private SpriteRenderer healthbar;
    	private Vector3 healthscale;
    
    	void start(){
    		healthbar = GameObject.Find ("HealthBar").GetComponent<SpriteRenderer> ();
    		healthscale = healthbar.transform.localScale;
    	}
    
    	void update(){
    		if (Health <= 0) {
    			Application.Quit ();
    			Debug.Log ("The game should quit right now.");
    		}
    		if (Health > 100) {
    			Health = 100;
    		}
    
    		HealthUpdate ();
    	}
    
    	void HealthUpdate(){
    		healthbar.transform.localScale = new Vector3 (healthscale.x * Health * 0.01f, 1, 1);
    	}
    
    }

Change your start and update function to Start and Update (first letter uppercase)