Submarines use a technology called "sonar" that bounces sound waves off of objects in the water. The sonar operators measure how long it takes for the signal to return to them. The information they get from sonar allows them to know

Ibelieve its because the stove is a cleaner burning fuel

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).