What is wrap doorknob in aluminum foil when home alone?

It's a common safety tip to wrap your doorknob in aluminum foil when you're home alone. The reason for this is that if someone tries to open the door from the outside, the foil will make a crinkling noise. This noise can alert you to the fact that someone is trying to enter your home, giving you more time to take action to protect yourself. It's also a good idea to have a plan in place for what you should do if you hear this noise or otherwise suspect that there may be an intruder in your home. This might include calling the police, finding a safe place to hide, or having a weapon for self-defense.