Chemistry Concepts Covered from National Science Standards:

1. Force and Motion

2. Energy

3. The Universe and its Happenings

MATERIALS:

1. Three empty soda or juice cans

2. Two Styrofoam cups

3. Lighter fluid

4. A match

5. Goggles

PROCEDURE:

1. With a can opener, cut the tops of the cans as follows:

TOP CAN: open on top of can and half of the bottom removed.

MIDDLE CAN: open on both ends.

BOTTOM CAN: only the top removed, leave bottom closed.

2. Connect the three cans on top of each other with masking tape or duct tape

3. Punch a hole about 2 cm in the bottom can on the side about 1/2 cm in diameter (i.e.. use a large nail).

4. Tape the two Styrofoam cups together rim to rim and place it tightly in the top opening.

5. Place two or three squirts of light fluid in the bottom hole and shake the stack of cans.

6. Let the stack stand for a few minutes. You are now ready for ignition!

7. Strike a match and hold the flame close to the bottom opening.

8. BE CAREFUL, KEEP AWAY FROM THE CANNON BALL!

QUESTIONS:

1. What are the two baffles in the cans for?

2. What purpose did shacking the stack of cans have?

3. What kind of energy resulted from the chemical explosion?

4. What other kinds of liquids do you think could be use in place of lighter fluid?

RATIONALE:

The baffles were left in the cans to enhance the mixing of the fuel with the air in the cylinder. The baffles momentarily retain and reflect the heat of the ignition to ensure combustion of the fuel. The shaking of the cylinder was done immediately after the fuel was added for exactly the same reason. The better the mixture of fuel vapors and the air, the better the explosion. The chemical energy stored in the lighter fluid is transformed by the combustion into kinetic energy of the moving cannon ball. Gasoline or alcohol may be used instead of lighter fluid.

APPLICATION: internal combustion engine; liquid fuel rockets

PREPARED BY: Annette Hynes

TAKEN FROM: Dale Kyser and Roger Gray, physiology teachers of Garden County High School, Oshkosh, Nebraska.