function Firework(){

  this.hu = random(255)
  this.firework = new Particle(random(width),height,this.hu,true);
  this.exploded = false;
  this.particles = [];



  this.update = function(){
    if (!this.exploded){
    this.firework.applyForce(gravity);
    this.firework.update();
    if(this.firework.vel.y>=0){
      this.exploded = true;
      this.explode();
    }
  }
  for (var i = this.particles.length-1; i >= 0; i--) {
    this.particles[i].applyForce(gravity);
    this.particles[i].update();
    if (this.particles[i].done()){
      this.particles.splice(i,1);
    }
  }
  }

  this.done = function(){
    if (this.exploded && this.particles.length == 0){
      return true;
    }
    else return false;
  }

  this.explode = function(){
    for (var i = 0 ; i<100;i++){
      var p = new Particle(this.firework.pos.x,this.firework.pos.y,this.hu,false);
      this.particles.push(p);
    }

  }

  this.show = function(){
    if(!this.exploded)
    this.firework.show();
    for (var i = 0; i < this.particles.length; i++) {
      this.particles[i].show();
    }
  }

}