A gravity bong, also known as a geeb, is a makeshift device used to smoke cannabis or other smokable substances. It is made from two plastic bottles, one of which is filled with water and the other with the substance to be smoked. The two bottles are connected by a hole in the bottom of the water-filled bottle, and the substance to be smoked is placed in the hole. When the user inhales through the mouthpiece of the water-filled bottle, the water level drops, creating a vacuum that draws the smoke from the other bottle into the user’s lungs.
Gravity bongs are popular among cannabis users because they are easy to make and use, and they can produce a large amount of smoke. However, they can also be dangerous, as they can cause users to inhale harmful toxins and carcinogens.