2B50.10 • Expanding Liquid

Photo shows the demonstration used at the University of Texas at Austin.

---

Concepts Conveyed:

• This demo shows the properties of liquids due to thermodynamics, namely the ideal gas law. Since the pressure remains constant, the volume that the liquid is taking up increases with temperature and decreases as it cools.

---

Instructions / Notes:

• Add or remove the flasks from the hot plate to see how the changes in temperature effect the volume.
• The water in the flask on the hot plate will rise as it is heated. As the it cools, it will shrink back into the flask. It may take some time to see either, especially during the cooling process, but the marks made at the start will help identify the change.
• Remove the flask from the hot plate after 15 minutes.
• If the water reaches the black line, remove the flask from the hot plate to prevent overflow.

---

Demo Staff:

About 15 minutes before class, heat one of the flasks on max heat.

Leave one flask unheated, so the professor can heat it on their own during class if they so choose.

Last updated on January 23, 2025