AddForce made a ball fall with no accelleration

Hi all, I hope I do not ask a stupid thing with this question.

I have a ball with rigidbody and a script that uses:

// This code is simplified for example
    void Update(){
        if(Input.KeyCodeDown(KeyCode.Space))
           rigidbody.AddForce(new Vector3(0, 0.2, 1) * forceModifier);
    }

Why the ball have the same speed when it goes up and when fall?
What’s wrong in my code?

Try using ForceMode.Acceleration. Because if I’m not mistaken the default ForceMode is ForceMode.Force. Which will add a constant force. Acceleration adds a constant acceleration to the rigidbody.