Investigating rockets – key terms
Taking science and technology to new heights. Rocket science includes ideas of forces and motion, how rockets work and some of the challenges for those wanting to make rockets go faster and higher.
This resource provides explanations of the key concepts encountered when investigating rockets – the ‘basics’ that every student should understand.
Rocket
A vehicle or missile that produces thrust in one direction by ejecting high-speed gases in the opposite direction. Rockets carry all of their own propellant.
Chemical rocket
A rocket that burns a fuel with an oxidiser inside a combustion chamber. The gases produced by this chemical reaction are ejected to create thrust.
Ablative coating
A sacrificial layer placed over a structure to protect it from intense heat. Tiny hot fragments break off to carry heat energy away from the surface.
Gas pressure
The force on a given area caused by gas particles pushing against each other and against a surface. High gas pressures inside the combustion chamber and their ejection from the chamber creates thrust.
Thrust
The reaction force that pushes a rocket in one direction as propellant is pushed in the opposite direction.
Propellant
The material that is used to create a pressurised gas that creates thrust when released. For a chemical rocket, the propellant is the fuel and oxidiser.
Combustion chamber
The part of a chemical rocket where the fuel reacts with the oxidiser. The resulting gases are ejected from the nozzle to create thrust.
Newton’s first law
An object will remain at rest or keep moving at a constant speed in a straight line unless there is an unbalanced force.
Newton’s second law
Force = mass x acceleration (also stated as acceleration = force divided by mass). An object accelerates more quickly if there is a greater force pushing it. Also, it is harder to accelerate an object if it has more mass (kilograms).
Newton’s third law
For every force acting on one object, there is an equal but opposite force acting on a different object (also called action and reaction forces).
Space
The region beyond the significant atmosphere of the Earth. Space officially begins at an altitude of 100 km above sea level.
Resultant force
The overall force that acts on an object. For straight-line motion, the resultant force is the sum of the individual forces acting in one direction minus the forces acting in the opposite direction. An object will always change its velocity in the same direction as the resultant force.
