User:Chris Horvatich

Objective:

This activity is written for students of all ages. Students will become familiar with a chemical reaction of acids and bases.

Materials:

* baking soda * Plastic film canister, where lid is male. * 8 1/2 x 11 paper * tape * scissors * water * Bleach * rocket template * vinegar * baking soda * chalk * soda bottle * balloons * cork to fit soda bottle

Strategy:

1. Pour a tablespoon of water into a film can. 2. Drop about 7 drops of bleach into the water. Notice the fizz. 3. Break up two seltzer tablets and place them into the soda bottle. 4. Pour 1/4 cup of water into the bottle and quickly put the opening of the balloon over the top of the bottle. Swish the contents of the bottle around several times and observe what happens to the balloon. The balloon should blow up. 5. Pour another tablespoon of water into the film can and drop in another 1/2 seltzer tablet. 6. Snap on the lid of the film can, and stand back. The lid should come off with a pop. 7. Repeat step 5 + 6 using the baking soda and vinegar. Rap some baking soda in a piece of light paper to delay the reaction some so you can get the film can lid on. 8. You may repeat steps 5 + 6 again, this time using a small piece of chalk and vinegar. This however may take some time, as the chalk dissolves very slowly. 9. Repeat steps 5 + 6 using any combination of fuel, the soda bottle and the cork on top. Do this one outside however, as the cork may come off with considerable force. Put the cork on snuggly. Cool! 10. The culminating event is to use the rocket template (click here for the template) to make a rocket out of a film canister. 11. Take the film canister and place it upside down. 12. Take an 8 1/2 x 11 sheet of paper, and tape it to the film canister, leaving the lid portion about 1/4'' from the bottom of the paper. 13. Roll the paper around the film canister creating a fuselage. 14. Using the rocket template, cut off the corners, fold them at the perforated line, and tape them to the bottom of the rocket slightly above the film canister. These are your fins. Should have at least three. 15. Cut out the center circle from the template, and cut the slit that is marked to the center of the circle. Twist it around to make a cone for the tip of the rocket. Tape it on. With a little decorating, your rocket is now ready. 16. Try the various fuels to propel your rocket, and record the results. If the paper on the rocket gets too wet, make another rocket, they are easy.

Wrap Up:

When you added the seltzer tablets to water, a chemical reaction took place producing gas bubbles. You could hear the gas fizzing in both the open film can and the bottle. It was the gas from the seltzer that blew up the balloon and it was the pressure of this gas that popped the top of the film can.

What Happened?

When a seltzer tablet dissolves in water, a chemical change takes place and carbon dioxide gas (CO2) is formed. Most seltzer tablets contain a base called sodium bicarbonate (baking soda) and dehydrated citric acid. When the tablet is place in contact with the water, the citric acid combines with the baking soda. Acids and bases undergo a chemical reaction when they mix, producing a gas and salt. In the closed container, the newly created gas has no place to go since the closed container is already full of air. This is like trying to add more air to a balloon that is already full. The pressure inside the container eventually escapes by blowing up the balloon, blowing out the cork, or blowing off the lid. This is the same thing that happens when you open a can of soda. You notice the fizz that it makes. The carbon dioxide rushes out, making a woosh sound.

Performance Assessment:

* Students will demonstrate the ability to work scientifically and accurately in the lab. * Students will make a hypothesis as to how and why the different propellants worked. * Students should analyze error in the technique that may have affected results.