When someone mentions bottle rockets, do you envision
placing a firecracker attached to a stick into a glass bottle and
launching it?
Water rockets have been a source of entertainment
and education for many years. They are usually made with an empty
two-liter plastic soda bottle by adding water and pressurizing it
with air for launching (like the image to the right).
Soda companies began using plastic bottles in 1970.
The Polyethylene Terephthalate (PET) material used in most plastic
soda bottles today was introduced in 1973.
Water rockets are used in schools to help students
understand the principles of aeronautics. The Science Olympiads
provide challenges of bottle rocket design and flight, including
altitudes and distances reached. Many interesting designs and additional
information on bottle rockets can be found with a simple Web search.
Teachers and students provide the following feedback
to the Secondary Science Education Department at the University
of Nebraska:
"Two-Liter
Pop Bottle Rockets may well be the GREATEST PHYSICAL SCIENCE TEACHING
TOOL EVER CREATED!!" Middle grades students can manipulate
and control variables, see their hypotheses verified or refuted,
and graph their findings. High school students experience the
nature of science at its best. They can document their abilities
with the following concepts: inertia, gravity, air resistance,
Newton's laws of motion, acceleration, relationships between work
and energy or impulse and momentum, projectile motion, freefall
calculations, internal and external ballistics, and the practice
of true engineering.
How
could something that sounds so simple be so complex? Open your mind
to the science and mathematics behind this educational "toy."
Below are links to a brief history timeline of rocketry, a comparison
between water rockets and a NASA rocket, and additional information
on the parts of a water rocket.