Solid Propellants
A propellant is basically an explosive substance that is used to make an object move. When propellants burn they release a lot of pressure and fire. The pressure and fire pass through a nozzle, which is the place where they are released in order to push an object like a rocket away from Earth. So in general, rockets work because of a controlled explosion. In almost all cases, solid propellants contain three substances. First there is an Oxidizer, which contains a large amount of Oxygen that supplies the Oxygen for the explosion. There are three oxygen atoms in the Oxidizer for Black Powder. The second element is a fuel, usually a hydrocarbon which is something that burns. Finally, solid propellants require a Binder which holds the Oxidizer and the Fuel together so that they do not fall apart.
When one is measuring the effectiveness of a solid propellant, one can look for the following traits to check a propellants effectiveness: