In years past, science teachers toiled with old-fashioned rocket construction projects and cringed at the idea of students burning their fingers upon the ignition of the burning engines. Subsequently, today’s science teachers are looking for safe and efficient ways to demonstrate rocket propulsion. As a possible solution for today’s teachers, the Aquapod from Great American Products presents teachers with a device that demonstrates rocket propulsion using the apparatus, a bicycle pump, water, and an empty two-liter bottle.
The two-liter bottle works like a balloon in that air injected from the bicycle pump pressurizes the bottle. Once the bottle is pressurized, a string is pulled to release the bottle from the launch platform. As air leaves the bottle, a force accompanied by an equal-and-opposite reaction force (Newton’s third law of motion) propels the rocket in the air. Hence, increasing the pressure inside the bottle creates increased thrust since the air inside the bottle escapes rapidly (Newton’s second law of motion). Also, adding water to the bottle (1/3 of the bottle) increases the action force. This is because the water is ejected from the bottle before the air, which makes the rocket propel nearly 100 feet if the conditions are right.
Included with the Aquapod are written maintenance and operating instructions that will help maximize the life and safe use of the rocket launcher. As a suggestion, make sure that you read these instructions for a successful launch. Undoubtedly, it is important to adhere to the instructions (e.g., “Fill the bottle to be launched with water to about 1/3 its capacity”). Otherwise, the rocket will not soar anywhere near the advertised altitude of 100 feet. In addition, we found that the tire pump that was used needed to be pumped at least 15 times to maximize the pressure to arm the rocket. The device appears reliable and is durable. If used properly, it should provide exciting demonstrations of force and motion for several years.