In this lab, students calibrate an unmarked thermometer*, then use it to measure room temperature. This is a great real world application of thermal expansion and a super simple laboratory activity. There are step by step instructions, along with an introduction to help them understand and complete the lab.
*You can easily order unmarked thermometers from a science supply source. Alternately, if you have those cheap thermometers with the scale on the metal backing, carefully remove the thermometers for this lab. Be sure to have extras as they are very fragile and I always have one or two a year that get dropped!