Object: a smoke detector with battery (might want to test it beforehand)

Good morning, boys and girls. How many of you have seen one of these around your house? Can you tell me what it is? That's right, it's a smoke detector. A smoke detector can sense if there is smoke in the air. Usually, if there is smoke in the air then that means there is a fire nearby. And a fire can be a very dangerous thing. So we keep smoke detectors around the house to let us know if there is a fire starting somewhere. If smoke gets around a smoke detector, it makes a loud noise. You might want to cover your ears for this, okay? (Wa…