Master Electrician Dad Teaches Son how to control motors and lighting with a contactor, thoughts?

What happens here

This video, featuring a master electrician, provides an educational overview of electrical contactors and their crucial role in safely controlling motors and lighting, particularly in HVAC systems. It demonstrates key diagnostic steps for an air conditioning unit that isn't running, including checking the thermostat and outdoor disconnect for voltage. The core of the instructional content focuses on identifying a failing contactor by its characteristic "chattering" sound, signaling the need for replacement.