We CAN check our assumption about unbending the neck. The only thing we have to do is measure the volume of the neck and calculate the volume of the neck from our measurements and see how closely they match. We can use the same process to measure the volume of the neck as we did the mouthpiece – block one end, fill with water, and weigh the water. Here’s the result:

Thirty eight cubic centimeters. Our neck is a frustum and the formula for its volume is:

We’re off by only 1.1 cubic centimeters or in terms of percentages 3%. That’s really not too bad.