In this 50-minute activity for grades 3-5, students construct a simple thermometer using 2-liter bottles, straws, and an alcohol-water mixture. The main objective is to help young students understand the difference between temperature and thermal energy. A printable student worksheet, temperature conversion worksheet, assessment ideas, and vocabulary lists are included. This activity is part of a module titled “”How Hot Is It?”” See Related items on this page for a link to the full module. Teach Engineering is an NSF-funded Pathway developed to provide high-quality experiential learning materials for K-12 classrooms.