There are three factors affect the heat transfer that is necessary to change an object’s temperature? Which is not included?

d. Substance and phase of the substance

Heat and Heat Capacity

Cohesion and Adhesion Water molecules stick to each other as a result of hydrogen bond- ing. An attractive force that holds molecules of a single substance together is known as cohesion. Cohesion due to hydrogen bonding between water molecules contributes to the upward movement of water from plant roots to their leaves. Related to cohesion is the surface tension of water. The cohe- sive forces in water resulting from hydrogen bonds cause the mol- ecules at the surface of water to be pulled downward into the liquid. As a result, water acts as if it has a thin “skin” on its sur- face. You can observe water’s surface tension by slightly overfill- ing a drinking glass with water. The water will appear to bulge above the rim of the glass. Surface tension also enables small crea- tures such as spiders and water-striders to run on water without breaking the surface. Adhesion is the attractive force between two particles of differ- ent substances, such as water molecules and glass molecules. A related property is capillarity (KAP-uh-LER-i-tee), which is the attrac- tion between molecules that results in the rise of the surface of a liquid when in contact with a solid. Together, the forces of adhe- sion, cohesion, and capillarity help water rise through narrow tubes against the force of gravity. Figure 2-11 shows cohesion and adhesion in the water-conducting tubes in the stem of a flower. Temperature Moderation Water has a high heat capacity, which means that water can absorb or release relatively large amounts of energy in the form of heat with only a slight change in temperature. This property of water is related to hydrogen bonding. Energy must be absorbed to break hydrogen bonds, and energy is released as heat when hydrogen bonds form. The energy that water initially absorbs breaks hydro- gen bonds between molecules. Only after these hydrogen bonds are broken does the energy begin to increase the motion of the water molecules, which raises the temperature of the water. When the temperature of water drops, hydrogen bonds reform, which releases a large amount of energy in the form of heat. Therefore, during a hot summer day, water can absorb a large quantity of energy from the sun and can cool the air without a large increase in the water’s temperature. At night, the gradually cooling water warms the air. In this way, the Earth’s oceans stabilize global temperatures enough to allow life to exist. Water’s high heat capac- ity also allows organisms to keep cells at an even temperature despite temperature changes in the environment. As a liquid evaporates, the surface of the liquid that remains behind cools down. A relatively large amount of energy is absorbed by water during evaporation, which significantly cools the surface of the remaining liquid. Evaporative cooling prevents organisms that live on land from overheating. For example, the evaporation of sweat from a person’s skin releases body heat and prevents over- heating on a hot day or during strenuous activity. Adhesion Cohesion Hydrogen bonds Cohesion, adhesion, and capillarity contribute to the upward movement of water from the roots of plants. FIGURE 2–11 www.scilinks.org Topic: Hydrogen Bonding Keyword: HM60777 mb06se_cols03.qxd 5/18/07 10:47 AM Page 41 42 CHAPTER 2 Density of Ice Unlike most solids, which are denser than their liquids, solid water is less dense than liquid water. This property is due to the shape of the water molecule and hydrogen bonding. The angle between the hydrogen atoms is quite wide. So, when water forms solid ice, the angles in the molecules cause ice crystals to have large amounts of open space, as shown in Figure 2-12. This open space lattice structure causes ice to have a low density. Because ice floats on water, bodies of water such as ponds and lakes freeze from the top down and not the bottom up. Ice insulates the water below from the cold air, which allows fish and other aquatic crea- tures to survive under the icy surface.

air mass a large area of air that has uniform temperature, humidity, and pressure. air pressure the force that a column of air applies on the air or a surface below it albedo the measure of the sun's reflectivity on Earth's different surfaces atmosphere the layers of gases surrounding Earth climate average weather conditions in a specific region over a long period of time coriolis effect the movement of wind or currents in a curved path due to Earth's rotation eddy Smaller, temporary loops of swirling water that can travel long distances before dispersing front a boundary between two air masses greenhouse gas a gas in the atmosphere that absorbs part Earth’s outgoing infrared radiation gyre a large circular system of ocean currents. humidity the amount of water vapor in the air hydrosphere system containing all the solid and liquid water on Earth jet stream Narrow bands of high speed wind high in the troposphere that move from west to east land breeze Winds that blow at night from land toward the sea. This is due to the fact that land has a low specific heat capacity and cools faster than water. This creates high pressure over the land at night and thus wind. local winds Winds that blow over short distances polar easterlies cold winds that blow from the east to the west near the North Pole and South Pole. prevailing wind distinct wind patterns caused by differences in pressure and the Coriolis effect sea breeze Winds that blow during the day from the sea toward land. This is due to water having a high specific heat capacity and it does not heat or cool quickly. High pressure then forms over the water during the day and blows toward the land. specific heat capacity The amount of heat that must be added to a substance to increase the tempurature by one degree Celsius storm surge water that has blown outward from the center of a tropical cyclone or hurricane and creates an abnormal rise in ocean waters on the coast surface current Currents near the surface of the ocean. Driven by wind, the Coriolis effect, and continental deflection trade winds Steady winds that flow from east to west between 30°N latitude and 30°S latitude along the equator tropical cyclone a rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters typhoon a tropical cyclone occurring in the Pacific Ocean; especially in the region of the Philippines or the China Sea. weather the short-term atmospheric conditions in a given place and time westerlies steady winds that flow from west to east in the middle latitudes (30- 60 Degrees). These impact our weather in the US. wind shear A large shift in wind speed and

Heat and Effects of Light , Sound, and Heat

Heat and Temperature

Heat and Phase Change

Heat and weather changes

Heat and Light

Heat and Matter

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