Questions relating to tube sealants, like the products named Slime or Stan's.
Sealants are liquid products added to a tube to prevent minor punctures from turning into full-blown flats. Some tubes come with sealant inside at purchase, and others are added afterwards by the user.
The sealant distributes itself around the inside of the tube because of the forces of riding. So when you get a puncture there's sealant ready to bubble out that spot and dry/set when it hits the lower atmospheric pressure. This retains most of the air in the tyre allowing you to keep riding without a tube swap.
Those who ride tubeless often have sealant inside the tyre instead of their tube.