AIM OF THE EXPERIMENT: To demonstrate jet propulsion.
MATERIALS: a metre-long wooden strip, a drinking straw (10 cm), scissors, string, two chairs, a 20 cm balloon, sticky tape.
MATERIALS: a metre-long wooden strip, a drinking straw (10 cm), scissors, string, two chairs, a 20 cm balloon, sticky tape.
Изображение
Cut 4.5 m of string and thread it through the straw.
Stand the chairs 4 metres apart.
Pull the string as taut as you can and tie it to the chair backs.
Blow the balloon up and twist its neck.
Move the straw up to one of the chairs and tape the balloon to the straw with its neck facing that chair.
Untwist the balloon.
RESULTS: The straw, with the balloon attached to it, shoots off along the string and stops only at the very end of the string, or else only when the balloon has completely deflated.
WHY? You have watched jet propulsion. That is the name given to the motion of a body which arises when a part of the body separates from it at some speed. When we let the balloon go, its walls pushed the air out. The air rushed backwards out of the balloon, while the balloon itself shot forward and pulled the straw after it. The straw and the string held the “rocket” on a straight course.
Stand the chairs 4 metres apart.
Pull the string as taut as you can and tie it to the chair backs.
Blow the balloon up and twist its neck.
Move the straw up to one of the chairs and tape the balloon to the straw with its neck facing that chair.
Untwist the balloon.
RESULTS: The straw, with the balloon attached to it, shoots off along the string and stops only at the very end of the string, or else only when the balloon has completely deflated.
WHY? You have watched jet propulsion. That is the name given to the motion of a body which arises when a part of the body separates from it at some speed. When we let the balloon go, its walls pushed the air out. The air rushed backwards out of the balloon, while the balloon itself shot forward and pulled the straw after it. The straw and the string held the “rocket” on a straight course.