Experiment

1. Undo the top of the battery filler and toss the tube aside.
2. Use a Philips screwdriver to make a single hole near the center of the filler.
3. Carefully take apart the spark igniter handle. Remove the nut and washer, as well.
4. Insert the igniter through the opening in the filler. Push it through until you can see the threading.
5. Reassemble the igniter. Start by screwing the nut and washer back in place. Make sure it’s tight! It helps if you onto the igniter from the inside.
6. Test the spark igniter.
7. Place 10-15 drops of rubbing alcohol inside of the filler.
8. Insert the ping pong ball into the opening and ensure a snug fit.
9. Ignite for a good pop or remove the ping pong ball to observe the ignition inside!

In case of a fire inside the filler, cover the hole with a plate or similar object.

How Does It Work?

If you take ball out of the popper, you get to witness what was happening inside.. combustion! That handy little spark igniter serves its purpose by igniting the vapors from the rubbing alcohol inside of the popper.

When the rubbing alcohol vapors are ignited, the resulting combustion causes the air inside of the popper to expand rapidly. The rapid expansion looks all over inside of the popper for a way to relieve all of the air pressure. When the air pressure finds its way out, this is called the point of least resistance. In this case, the point of least resistance is the seal between the ping pong ball and the popper

Now, the ping pong ball is squeezed into the popper pretty tight, so it takes a lot of air pressure to pop the ping pong ball. This is due to friction. Once the air pressure exceeds the necessary force to overcome the friction, the force blasts the ball off and away!