The idea of traveling space has inspired the minds of writers, artists, and inventors for centuries.
While the discoveries and innovations in this field remain endless, rocket science has greatly advanced since humans first imagined it. It is, indeed, a challenging but exciting field, but the fundamentals of rocket science can be understood through Newton’s Laws of Motion.
First, what is a rocket? Technically speaking, a rocket is any vehicle that uses jet propulsion to accelerate without using the surrounding air. It can be as large as the space rockets created by NASA, or as small as something launched from your own backyard!
Here’s how the three Laws of Motion play a role in rocketry:
Newton’s First Law
Objects at rest remain at rest and objects in motion remain in motion in a straight line unless acted upon by an unbalanced force. What does this mean for rockets?
Scientists have to figure out how an object at rest, such as the rocket, can be moved with enough exertion in order to lift off. For lift off to happen, the force exerted must be greater than the force of gravity. This force is called thrust. In sending rockets to space, figuring out how to generate enough thrust to quickly propel a large amount of weight against gravity is incredibly challenging!
Newton’s Second Law
Force equals mass times acceleration (or f = ma). In rocketry, this means that the force or thrust produced is as great as the amount of propellant or fuel (m) used and the acceleration (a) of the combustion products out of the nozzle. In other words: the more propellant and acceleration, the greater the force or thrust, which is important in successful launches.
Newton’s Third Law
For every action there is an equal and opposite reaction. The combustion of propellants when rockets lift off is the action—the reaction is the rocket moving in the opposite direction. Upon lift off, while the propellants accelerate rapidly, the rocket itself slowly accelerates, which may seem like an imbalanced or unequal reaction. What is happening here can be explained by another Newtonian law: the Law of Inertia, which states that it takes a force to change the motion of an object. The greater the mass, the greater the force required to move it. Since the mass of the rocket is much greater than that of the gas, smoke, and flame produced by the propellant, more force is required.
Of course, actual rocket science is much more complex, as there are numerous other factors to consider like:
The weight of the rocket in relation to the force or thrust that can feasibly be produced
The materials used as propellants
The purpose of the rocket in relation to the size
Its safe return
Its environmental impact
And many more!
Learn more about the basics of how rockets work by visiting the Science Mill! This month’s Homeschool Day will focus on activities exploring rocket science, and you can check out the museum’s rocketry exhibit from Wednesday to Sunday. Learn more about admission here.