How to make a simple thermometer

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 mark it as 0℃ after the red ink in the straw is stable.

3. Put the vial into boiling water and mark it as 100℃ after the red ink in the straw is stable.

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