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Name ___________________________________________ Date ______________________ Class ________________________To study the phase changes as water is heated from solid to liquid to water vapor. Melting, boiling, freezing, condensation: these are all things you have experienced in your daily life. You have seen water change phases over and over again, but have you ever taken time to think about why it happens? Did you know that phase changes either absorb energy or release energy? Vaporization Depending on the temperature, most substances can exist as both a solid and a liquid. A substance in itsliquid state has more thermal energy than it has in its solid state. The temperature at which the transitionfrom a solid to a liquid takes place is the melting point of the substance. The molecules that make up a gas have more thermal energy than molecules of the same substance in the liquid state. The liquid molecules are in close contact with each other while gas particles are spaced significantly further apart. The transition from a liquid to a gas is known as vaporization and occurs by either evaporation or boiling. The normal boiling point is the temperature at which the substance boils at sea level. Melting and vaporization points are characteristic properties of a substance. Chemists often use these points to help identify or classify a substance. In this activity you will observe the temperature change as water is chilled by ice and the ice melts due to stirring and being out at room temperature. Then you will heat up the water until it boils and watch how the temperature changes in that process.