Ask A Scientist

How does the engine in a rocket shoot it up?

Asked by: Alex Shanks
School: Tioga Hills Elementary School
Grade: 1
Teacher: Mrs. Mastrogiovannii
Hobbies/Interests: Fly planes, shoot up rockets and soccer
Career Interest: Soccer player

Answer from George Catalano

Professor of Mechanical Engineering, Director of t

Research area:
Turbulence, Fluid Mechanics, Aerodynamics, Environmental Ethics, and Modeling Ecosystems

PhD school:
University of Virginia, Aerospace Engineering, 1977

All things Italian, Creative Arts, Model trains & cars

Wife, Karen, is a registered yoga teacher at Yoga for Everybody at the Orthopedic Associates; lives with 3 Alaskan Malamutes, two more in our hearts

First, let's explore what we mean when we use the word 'rocket.' In fact, a rocket can be any vehicle which is propelled by the ejection of gases at the rear of the object. Typically the exhaust gases are produced by combustion or burning of self-contained propellants. A rocket moves in the opposite direction of the exhaust gases. That is the reason rockets are pointed towards the heavens! Think back to photographs you have seen of the rockets that are launched at Cape Canaveral. The gases move rapidly towards the Earth with the resultant reaction force quickly accelerating the rocket up towards the stars. In addition to space exploration, rockets are used in fireworks, in military weapons, and in many other scientific applications such as in meteorology. Did you know that one of the first rockets known to humankind was in the form of a pigeon that successfully flew above the countryside in the southern Italian province of Puglia? According to NASA, one of the first devices to successfully employ the principles essential to rocket flight was this wooden bird. The writings of Aulus Gellius, a Roman, tell a story of a Greek named Archytas who lived in the city of Tarentum, now a part of southern Italy. Somewhere around the year 400 B.C., Archytas mystified and amused the citizens of Tarentum, present day Taranto, by flying a pigeon made of wood. Escaping steam propelled the bird suspended on wires. The pigeon used the action-reaction principle, which was not stated as a scientific law until the 17th century. In the first few centuries of the Common Era, the Chinese began experimenting with the gunpowder-filled tubes. At some point, they attached bamboo tubes to arrows and launched them with bows. Soon they discovered that these gunpowder tubes could launch themselves just by the power produced from the escaping gas. The true rocket as we have come to know it was born. It was not until the latter part of the 17th century, however, that the scientific foundations for modern rocketry were described by the great English scientist Sir Isaac Newton (1642-1727). Newton organized his understanding of physical motion into three scientific laws that are known as the laws of motion. These laws explain how rockets work and why they are able to work in the vacuum of outer space.

Last Updated: 3/1/17