Play a particleSystem with code

Scripting
1

I need to play a particle system 10 secs after the game started, I create a public ParticleSystem variable and drop the ParticleSystem on the editor , then with a InvokeRepeating I call a function that have this line : particleSystem.Play();
but it give me the following error : Object reference not set to an instance of an object UnityEngine.ParticleSystem.Play (Boolean withChildren).

Someone knows the error ?? or knows how to do that ?

thanks !!

public class Fireworks : MonoBehaviour {
	
public ParticleSystem particleSystem = new ParticleSystem();

	    void Start()
    {
       
		InvokeRepeating("fireworks", 1.0F, 1.0F);

    }

		public void fireworks(){
		
		particleSystem.Play();
		
	}
	
}
2

Can you paste the code inside CODE tags so that we can see it? And even the exact error message line number and character would be awesome to help you figure out what’s wrong.

3

thanks for answer , now there is the code