Question

what is the process of evaporation? when you get out of a swimming pool on a windy day, your body sometimes feels cold. why? the water on your body is evaporating. evaporation is the change of state from the liquid state to the gas state. the reason you feel cold is because evaporation requires energy. the energy in this case goes from your body into the liquid water. liquid water changes state to a gas called water vapor. this change of state also happens when you sweat. sweat is mostly water. when sweat appears on your skin, the water absorbs heat (energy) from your skin. this causes the water to evaporate, and you feel cooler. evaporation and boiling evaporation can occur at low temperatures. water can evaporate at temperatures near 0°c, but it will evaporate very slowly. for water to evaporate quickly in an open container, it must be heated. if the water is heated to a high enough temperature, it will boil. boiling occurs when a liquid evaporates quickly. the particles leave the liquid state and change to vapor (gas) particles. this change creates a vapor pressure. a liquid boils when the vapor pressure equals the air pressure in the room. the temperature at which boiling occurs is known as the boiling point of the substance. like melting point, boiling point can help identify a substance. for example, the normal boiling point of water is about 100°c. many liquids that look like water boil at different temperatures. the figure below shows water evaporating at room temperature and water boiling. evaporation can happen in a liquid below its boiling point. some particles at the surface of the liquid move fast enough to break away from the particles around them. when they break away, they become a gas (or vapor). boiling happens in a liquid at its boiling point. as energy is added to the liquid, particles throughout the liquid move faster. when they move fast enough to break away from other particles, they evaporate. the bubbles you see when water boils contain water vapor. say it investigate people usually feel warmer on a warm, humid day than on a warm, dry day. investigate why most people feel warmer on humid days and report to the class. reading check 6. describe why does sweating help cool your body? reading check 7. identify when the vapor pressure of a liquid equals the air pressure in the room, what will the liquid do? take a look 8. identify are there more water vapor molecules above a beaker of water at room temperature or a beaker of water at its boiling point?

Explanation:

Answer:

(6) Sweat is mostly water. When sweat appears on the skin, the water absorbs heat (energy) from the skin. This causes the water to evaporate, and the body feels cooler.
(7) It will boil.
(8) There are more water - vapor molecules above a beaker of water at its boiling point.