1. Impractical Matters, Inc. “The Carbonator” aka Duct Tape Monster Brian Paul Nate Freeman Thomas Florian Tim Evans

2. The Process Dry ice, or frozen carbon dioxide, is placed in the bottle. Dry ice does not melt; it skips the liquid phase, becoming a gas in a phase change called sublimation. Since the density of the gas is less than that of the solid, the pressure increases inside the closed system. Hot water speeds up the process. The pressure is used to inflate a balloon, which in turn knocks a cart off a ledge. The cart is tied to a string which uses a system of pulleys to pull up on a gate latch as the cart falls, allowing a hinged arm to fall and strike a weight which pulls up the 1kg mass. For those interested, the cart and several parts of the pulley system are made from the Erector Set construction toy.

3. The Math The cart's mass is.3kg and it starts from a height of 14 inches. It is stopped by the string 2 inches above the datum. Given that positive is up, its final velocity can be found using conservation of energy: mgh =.5mV 2 (9.18m/s 2) (12in) 2.54cm 1m =.5V 2 V = -2.37m/s ( 1in )( 100cm ) The swinging arm is also 14 inches, but has a mass of.26kg. Since mass cancels out, this formula may look very familiar: mgh =.5mV 2 (9.18m/s 2) (12in) 2.54cm 1m =.5V 2 V = -2.37m/s ( 1in )( 100cm ) Kinetic energy for each item will be different, however, because it incorporates mass. KE =.5mV 2. Cart:Arm: KE =.5(.3kg)(2.37m/s) 2 =.839JKE =.5(.26kg)(2.37m/s) 2 =.722J

4. The Money $ $ $ Lumber$5.00 Dry Ice$6.00 PVC Pipe$1.00 Bottle$1.25 Hardware/Erector$5.00 Total$18.25

5. The Problems The team faced a number of challenges with our design and the plans were tweaked constantly throughout the build. The most notable issues were: ● Leaking of both CO 2 and water from the initial containers ● Resolved by: using a bottle designed to be sealed; lots of duct tape ● Gate latch too stiff ● Resolved by: more weight in the cart; filing tip of latch ● Weight not high enough to raise 1kg mass to 1meter ● Resolved by: raising weight on hinged platform ● Epoxy not strong enough ● Resolved by: using more duct tape