Jump when the screen is tapped, rather than when the space key is pressed

Question

I am trying to make my character jump when the player taps the screen.

At the moment it jumps when I press space bar, but how can I change the code to make him jump when the screen is tapped?

This code works as the character then jumps up:

void Update()
{
    if (Input.GetKeyDown(KeyCode.Space))
    {
        rb.gravityScale *= -1;
    }
}

This code using touch does not work: the character just stays where he is when I click the screen on my computer.

public void Update()
{
    if (Input.touchCount > 0)
    {
        Touch touch = Input.GetTouch(0);
        rb.gravityScale *= -1;
    }        
}

Answer 1

I changed the code to the following by adding a TouchPhase.Began to the if statement:

public void Update()
{


    if (Input.touchCount == 1)
    {
        if (Input.GetTouch(0).phase == TouchPhase.Began)
        {
            Touch touch = Input.GetTouch(0);

            rb.gravityScale *= -1;

        }
    }


}

Then testing it on a device using unity remote.