1. Put some red ink in the vial, tie a small hole with the same thickness as the straw on the lower rod on the side of the lid, insert the straw, and fill the direct gap between the straw and the small hole with clay.

2. Put the vial into the ice-water mixture, and the red ink in the straw will be marked as 0 C after it is stable.

3. Put the vial into boiling water, and the red ink in the straw will be marked as 100℃ when it is stable.

4. Divide the temperature range from 0℃ to 100℃ into a reasonable number of colored forks and mark them with Shaanxi degrees.