What is why aluminum foil on door knob?

There are several reasons why aluminum foil can be used on door knobs:

1. Protection against germs: Door knobs are some of the most bacteria-ridden objects we touch on a daily basis. Applying aluminum foil can protect you from coming into contact with germs that may be present on the surface of the knob.

2. Prevention against static electricity: If your door knob is made of metal, touching it can sometimes result in a static electricity shock. By wrapping the knob in aluminum foil, you can reduce the risk of this happening.

3. Privacy: If you want to prevent someone from getting into a room, you can wrap the door knob in aluminum foil to prevent them from turning it.

4. Decoration: Finally, aluminum foil can be used to decorate door knobs for special occasions such as Christmas or Halloween. It's a cheap and easy way to add some festivity to your home.