Name: j middle school
Date: Around 1993
How do space ships get off the ground?
Gravity pulls on any object near the earth, including you, and a spaceship.
To get off the ground, you have to push yourself up harder than the earth is
pulling you down. When you jump in the air, you are pushing against the
ground. When a bird flies, it is pushing against the air with its wings. A
spaceship (or rocket) pushes against its exhaust - the stuff that comes out
the back. Just as if you were sitting on a swing and threw a baseball
forward, you would move backwards. The harder you throw the baseball, the
more you will move. In the same way a rocket throws hot gasses out the back
and pushes itself forward. If it pushes hard enough, it "blasts off". If
it keeps pushing hard enough, it keeps going higher.
daniel n koury jr
Click here to return to the Engineering Archives
Update: June 2012