Linette Guare
Space Shuttle launcher with Alka-Seltzer
Concept: Pressure.
There are more molecules of gas being produced that cause more collisions, which causes more pressure.
Materials:
Directions:
1. Attach the picture or paper rocket / space shuttle to the top of film container with glue or tape.
2. Pour 15 mL of water into the container.
3. WEAR GOGGLES! Drop the tablet into the container and place the lid on.
4. CAUTION - Hold the container away from the body and do not point it at anyone. The lid should fly off.
Introduction:
My friend John has a friend who is an astronaut. Mission Specialist Dan Tani just returned a month ago aboard the Space Shuttle Endeavor from a trip to the International Space Station. John received e-mails from Dan in space. Dan said it was great to walk in space, but said his favorite thing about the whole experience was the take-off from the Kennedy Space Center.
Explanations:
Alka-Seltzer tablets are made of solid of baking soda, citric acid, and aspirin. When water is added: The hydrogen ion (H+ ) from the citric acid and bicarbonate ion (HCO3) from the baking soda in the tablet react to produce carbon dioxide gas (CO2). There are many molecules of gas being produced that cause more collisions, which causes more pressure within the film container. The build up of the pressure is what causes the lid to pop off. Even though the tablet seems to be disappearing, the matter is not being destroyed; it is just being converted to carbon dioxide gas.
Sodium bicarbonate + citric acid --> carbon dioxide + water + sodium citrate
bicarbonate ion + hydrogen ion (from citric acid)
HCO3-1 ion + H+1 -----> CO2 + H2O.
Safety Precautions: Wear goggles and be careful where you are pointing the container. It could cause serious injuries.
Waste Disposal: Dispose liquid down the drain.
Reference: Sarquis, A. M, and Woodward, L. M, J. Chem. Educ. 1999, 76, 385