Though not exactly accurate, it's a good way to make the point that touch screens don't respond to force (some mac products aside). My mom usually bangs harder

Though not exactly accurate, it's a good way to make the point that touch screens don't respond to force (some mac products aside). My mom usually bangs harder on the screen when it's unresponsive. That doesn't help. If you think of the screen as responding to body heat, that could teach the right gesture.