Lesson Summary Students build a bottle thermometer and use it to conduct investigations to find out what happens when it is placed in hot and cold water. Teacher Background Almost all liquids contract as they get colder, and expand as they get warmer. Water follows this pattern until it reaches 4° C. As water continues to cool after this temperature, it actually starts to expand. Water gets less dense as it cools from 4° C to 0°C, where it freezes. The hotter the water, the higher the indicator on the thermometer; the cooler the water, the lower the indicator Set-up/Management Tips You will need room temperature water, hot water and cold water for this investigation. Using a thermos and a cooler, can help maintain the temperature of the water until you are ready to use it. Be sure to use hot tap water (about 45° C). Boiling water will misshape the large plastic cups. Make the “green” room temperature water ahead of time in the dispensing bottle. One bottle holds enough water for 8 thermometers. You can have students use an index card behind the thermometer to mark “temperatures” and make the thermometer more useful. Literacy Support Books Available Through VAST Mediagraphies (see Literacy Links) Science Stories There are none for this part of Investigation 2. Scientific Vocabulary The following words are key vocabulary words that will be introduced in this lesson and reinforced throughout the unit: thermometer                        expand                                    contract