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