Task: Question Answering
Input (English): Background Paragraph: As Figure above shows, the distance between particles is much smaller for the solid and liquid states than for the gas state. In the solid state, particles are fixed in place, while particles are more free to move in the liquid and gas states. The particles in the solid and liquid states “stick together,” but in the gas state, they move freely about the container. In general, it requires energy to separate individual particles. If we want to make a solid adopt a liquid form, we can add energy in the form of heat, increasing the temperature of the substance. Conversely, if we want to convert a substance from a gas to a liquid or from a liquid to a solid, we remove energy from the system and decrease the temperature. Pressure also plays an important role in changes of state, which will be discussed later on. We will study these difference in greater detail in the chapter States of Matter. 
Story: Thomas and Alexander are freshman students in an introductory chemistry laboratory course at their local college. In this week's experiment, both Thomas and Alexander will be starting their experiments with liquid water. They both follow different experimental protocols, and at the end of the experiment Thomas discovers ice in his reaction flask, while Alexander discovers steam in his reaction flask. 
Question: Which person must have decreased the temperature of their reaction?
Output (English): Thomas.