Ch 12 SummaryI have learned that water exists in all three states of matter i.e. ice, liquid, gas. When water is in ice state then the molecules are tightly packed, in liquid state the molecules are less tightly packed while in gas state the molecules are free. Whenever state of water changes then heat exchange in surrounding. For example, when water evaporates then heat is absorbed. Sometimes energy is absorb in breaking the bond and temperature remains same and this energy is called latent heat. During evaporation energy is absorb and during condensation energy is released. Sublimation is the process by which solid changes directly into gas without passing through liquid phase. Humidity is amount of water in air. Humidity can be explained in three ways. The three ways are mixing ratio which is the ratio of mass of water vapor and mass of dry air, relativehumidity which is the ratio of actual water vapor in air and amount of water needed for saturation at that temperature and last one is dew point which is the temperature at which condensation starts. The process in which no heat is added or removed is called adiabatic process. I have studied wet as well as dry adiabatic processes.I have also studied processes that lift the air. I have studies four process and these processes are Orographic lifting is which air is rise above mountainous barrier, Frontal lifting in which warmerair is cooled, Convergence in which air there is upward movement and Localized convective lifting in which air is lifted due to buoyancy of air. Whenever air rises and cools, it forms clouds. If the rising air is cooler then surrounding then it returns back and this is called stable air and if the rising air is warmer than its surrounding then it continues to rise and this is called unstable air. When wet adiabatic rate is greater than lapse rate then it is called absolute stability while when lapse rate is greater than dry adiabatic rate then it is called absolute instability and when environmental lapse rate is between dry adiabatic and wet adiabatic then it is called conditionallyinstability. Tiny bit of particles called condensation nuclei acts as surface for condensation when condensation occurs at high above the ground. I have studied different types of clouds like Cirrusclouds which are high, white, and thin, Stratus clouds which consist of sheets or layers and Cumulus clouds which consist of globular cloud masses. Clouds can be low, middle or high. When clouds are low ground then they are called fog. Fog can be of many types like Fogs caused by cooling which is further classified into radiation fog which is formed by radiation cooling of the ground and adjacent air, advection fog which forms when warm air becomes cool when contact with cold surface below, and upslope fog which forms when humid air moves up. Other type is evaporation fogs which is further divided into steam fog which forms when unsaturated and cool air moves over a warm water body and frontalfog forms when moist air mass rise over cooler. Precipitation from cool clouds occurs in the middle and high latitudes by the process called Bergeron process. Precipitation from warm clouds occurs by the process called collision–coalescence process. Precipitation occurs in different types including rain, drizzle, and mist, sleet and freezing rain, hail, rime.I have studied that water is the only substance that exists in three states of matter and it is very useful substance. Without water life is not possible. But as we seen that now a days temperature is increasing and quantity of rain is decreasing. So we should try to take care of our atmosphere by taking different steps like plantation of trees. In this way we could save our atmosphere.I have a question for you guys why there are different types of