Xiaohong, it's too hot

1. When the temperature changes in different seasons, various physical changes will occur in the water: in spring, the melting of ice and snow is a phenomenon; It is a phenomenon that the water spilled on the floor in summer soon dries up. Both of the above States absorb heat when they change.

There is a device that can reflect the water vapor content in the air. It consists of two identical thermometers side by side, one of which is wrapped in a wet cloth. The readings of the two thermometers are different, and the reading of the wet bubble thermometer is lower (lower) because the water in the wet cloth absorbs heat when it evaporates.

3. When manufacturing metal tools, in order to increase the hardness of the workpiece, put the red-hot workpiece into cold water to make a fire, which will make a "squeaky" sound and emit "white smoke" on the water. This state change is an evaporation process.

4. The weather is very hot. Xiaohong is doing homework at home, sweating profusely. She looked up at the indoor thermometer and learned that the room temperature was 38 degrees, so she turned on the electric fan. At this time, she looked at the thermometer again and found its reading (fill in "increase", "decrease" or "unchanged"), but she felt much cooler because turning on the electric fan accelerated (airflow).