How does propulsion work?

What is chemical propulsion?

Chemical propulsion is propulsion in which the thrust is provided by the product of a chemical reaction, usually burning (or oxidizing) a fuel. A chemical reaction combines two or more kinds of chemicals and makes a different chemical as a product. A commonly used reaction is combining hydrogen with oxygen to make water.

Generally, the reaction also releases heat which will warm up the product. Since when you heat a substance it expands (try this with a crayon and a magnifying glass), the heat produced by the chemical reaction heats up the product, making it expand. As it expands, it gets too big for the reaction chamber and pushes out the back of the rocket. This provides thrust for the rocket.

What is a propellant?
How are rockets designed?
How does DS1's engine work?
What is the difference between an ion engine and a chemical one?

What are the types of rocket propulsion?
What is thrust?
Every action has an equal and opposite reaction?
How do things burn?

What is specific impulse?
What is a monopropellant?
What are some rocket propellants?
How do you calculate rocket engine performance?