"Fun with Astronaut Ice Cream--An Exercise in Understanding Phase Diagrams" is an engaging and fun way for beginning chemistry students to become familiar with phase diagrams and their associated terminology. When I taught a year-long, honors chemistry (SAT II preparatory) course to sophomores, I would introduce students to the phase diagrams for carbon dioxide and water and then demonstrate the fascinating phase change behavior near the triple point of carbon dioxide and the critical point of benzene using the old Chemistry Comes Alive videos which have now migrated to the ChemEd X video page. Then, to reinforce these concepts, I'd have them view the YouTube video, "Making astronaut ice cream in my home shop" and answer some related questions.
Figure 1: Phase Diagram for water, Chemistry 2e. Provided by: OpenStax. Located at: https://openstax.org/. License: CC BY: Attribution. License Terms: Access for free at https://openstax.org/books/chemistry-2e/pages/1-introduction (accessed 3/27/2023)
phase diagrams, phase transformations, triple point, critical point, normal melting and boiling points
Students will need the links to the videos and also the worksheet that includes the phase diagram for water.
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Watch the short video clips below with your students while pausing to take questions and explain concepts. Then have them view the ~10-minute YouTube video, "Making astronaut ice cream in my home shop". After that, have them examine the simplified phase diagram for water and answer the questions in the linked handout. I typically did this as an activity during a single, 50-minute class period, but it could just as easily be assigned as homework.
Video 1: Liquefaction of Carbon Dioxide - Part 1 of 4, Chemistry Comes Alive Volume 2, ChemEd X Vimeo Channel.
Video 2: Liquefaction of Carbon Dioxide - Part 2 of 4, Chemistry Comes Alive Volume 2, ChemEd X Vimeo Channel.
Video 3: Liquefaction of Carbon Dioxide - Part 3 of 4, Chemistry Comes Alive Volume 2, ChemEd X Vimeo Channel.
Video 4: Liquefaction of Carbon Dioxide - Part 4 of 4, Chemistry Comes Alive Volume 2, ChemEd X Vimeo Channel.
Video 5: Critical Point of Benzene - Part 1 of 3 - Introduction, Chemistry Comes Alive Volume 2, ChemEd X Vimeo Channel.
Video 6: Critical Point of Benzene - Part 2 of 3 - Temperature Increases, Chemistry Comes Alive Volume 2, ChemEd X Vimeo Channel.
Video 7: Critical Point of Benzene - Part 3 of 3 - Temperature Decreases, Chemistry Comes Alive Volume 2, ChemEd X Vimeo Channel.
Video 8: Making astronaut ice cream in my home shop, Applied Science YouTube Channel, accessed 3/21/2023.
Provide students with video links and student handout.
Phase Diagram for water, Chemistry 2e. Provided by: OpenStax. Located at: https://openstax.org/. License: CC BY: Attribution. License Terms: Access for free at https://openstax.org/books/chemistry-2e/pages/1-introduction (accessed 3/27/2023)