How do you create and calibrate a thermometer using a straw? (a drinking straw)?

Answer 1

You could. It is possible by using the straw's thermal coefficient of linear expansion. For example for polyethylene (I do not know what drinking straw is made off) it is 13.0 E-5 /deg C.
To measure the expansion you can use several methods two of then are:
1. Lever method where a light beam (16-18gage steel wire or a 6-10 cm sawing needle) with a pivot placed to give the straw 1:6 or 1:8 advantage. As the straw expands it will move the needle.
2. Mirror method is analogous to the lever method however the mirror is in motion and the reflection mark will move to indicate temperature.

The calibration is cumbersome since you have a mechanically sensitive instrument. I would place it under a glass dome outside and observed/ marked throughput a year or used an environmental chamber.

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