A hand grenade is a small explosive device that is thrown at a target. It can be used as a weapon against an enemy soldier or vehicle. The most common type of grenade is the fragmentation grenade. Fragmentation grenades send out lots of very fast, very small fragments when they explode. Hand granades are usually thrown, and explode soon after that. Some specially designed grenades are fired from rifles or specially made grenade launchers. There are grenades which contain tear gas. These are used to control riots.