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Heat Standard 4a/4d 4a-Students know the sun is the major source of energy for phenomena on Earth's surface; it powers winds, ocean currents, and the water cycle. 4d-Students know convection currents distribute heat in the atmosphere and oceans. p. 400-409 1. The earth receives energy from the sun in the form of Radiation. a. When radiation is absorbed, the energy is changed to heat. 2. Conduction a. Transfer of heat from one material to another. b. Heat transfers from a hot place to a cool place. c. Molecules move faster when they are warm. d. Molecules move slower when they are cool. 3. Convection a. The transfer of heat by the circulation of movement of liquid or gas. b. Rising and falling of warm and cool gas/liquid. 4. Greenhouse effect a. 20% of the radiation from the sun is absorbed by gases in the atmosphere and change to heat. b. When land and water absorb radiation i. Molecules move faster ii. Warming gas molecules 5. Global warming a. Is a rise in global temperatures b. Caused by an increase of CO2 i. Causing a rise in the sea level ii. Mixture of fresh and salt water 6. Keeping the Earth livable a. The amount of solar energy received and sent back into space must be equal. b. This is called Radiation balance Atmospheric Pressure and winds 7. Wind a. Moving air b. Wind is created by differences in air pressure c. Caused by unequal heating of the Earth. d. Low pressure at the equators i. Warmer air molecules ii. Less dense e. High pressure at the poles i. Cooler air molecules ii. More dense iii. Because air moves from high pressure to low pressure, the winds usually move from the poles to the equator. 8. Trade Winds a. Two different types: i. Local winds 1. Caused by uneven heating of the Earth’s surface. 2. Can blow from any direction 3. Move short differences (30 degrees Lat. To equator) 4. Early traders used the winds for trade. 5. Doldrums at the equator (no wind) a. Doldrums means foolish. i. Don’t get your ship caught there. 6. Horse Latitudes a. If ships got caught there, horses were thrown overboard to save fresh water. 9. Jet Streams a. Fast moving winds i. Located in the upper Troposphere and lower Stratosphere b. Used to: i. Predict weather ii. By airlines to conserve fuel. iii. Global winds 1. Caused by uneven heating of the Earth’s surface. 2. Travel in a specific direction 3. Move longer distances Standard 4b Students know solar energy reaches Earth through radiation, mostly in the form of visible light. p. 396-404 Layers of the Atmosphere 1. Troposphere a. Lowest layer of the atmosphere b. Almost all of the following are found in this layer i. Water vapor ii. Clouds iii. Life forms iv. Weather v. Air pollution vi. Carbon dioxide vii. Temp. drops with rise of altitude 2. Stratosphere a. Above the Troposphere b. Very thin c. Very little moisture d. Temperature rises with altitude i. This occurs because of ozone. 3. Mesosphere a. Above the stratosphere b. Coldest layer c. Temperature drops with rise of altitude d. Large wind storms 4. Thermosphere a. Upper most layer b. Temperature rises with altitude i. Because gases absorb radiation c. Temperature and Heat are not the same thing i. High temperature means molecules are moving faster ii. Heat means the transfer of energy of these molecules iii. Therefore, even thought the particles are moving very fast, they very rarely collide with each other. Standard 4e Students know differences in pressure, heat, air movement, and humidity result in changes of weather. p. 372-73, 403, 425-441, 448-49, 454, 457, 466, 478 1. Currents that Stabilize Climate a. Warm water currents warm the air near the land that they run. b. Cold water currents cool the air near the land that they run. 2. El Nino-warm water current a. El Nino not only effects surface waters, but also alters the interaction between the ocean and the atmosphere, causing changes in the atmosphere’s circulation. b. Cause: i. Flash floods ii. Mudslides iii. Lack of or increase of rain iv. See page 373 3. Humidity a. Is the amount of water vapor or moisture in the air. i. As water evaporates, humidity goes up. ii. As temperature goes up, the airs ability to hold water also goes up. iii. When the air holds as much water as it possibly can, (100% relative humidity) the air is considered to be saturated. 4. Condensation a. Is the process in which a gas (such as water vapor) changes to a liquid. i. Before condensation can occur, the air must be saturated. ii. See p. 427 5. Clouds a. Clouds are: i. A collection of millions of tiny water droplets and ice crystals. 1. As the rising air cools, it becomes saturated. 2. At saturation, the water vapor changes to a liquid, or a solid depending on the temperature. 3. In order for the water vapor to change states, it needs a solid to cling to such as dust, smoke, salt that is in the air. b. Kinds of clouds (see page 428-429) i. Three basic types 1. Cumulus a. Puffy, white with flat bottoms b. Indicate fair weather c. When they get larger i. They produce thunderstorms ii. Called cumulonimbus 1. When the word nimbus is used, it means there may be rain. 2. Stratus a. Form in layers b. Cover very large areas of the sky c. Caused by a gentle lifting of a large body of air into the atmosphere. d. Nimbostratus clouds cause light to heavy rain. e. When water vapor condenses near the ground, it forms a stratus cloud called fog. 3. Cirrus a. Thin, feathery white clouds found at high altitudes. b. Form when the wind is strong. c. May indicate bad weather if they thicken and lower in altitude. 6. Precipitation a. Is water, either in a solid or a liquid that falls to the Earth. b. 4 types of precipitation i. rain ii. sleet iii. hail iv. snow 7. Air masses and fronts a. Air masses are changes in weather caused by the movement of and interaction of large air masses. i. An air mass is a large body of air that has similar temperature throughout. b. Cold air mass i. Three cold air masses influence winter weather in the U.S. 1. They are: a. From Canada, North Pacific Ocean and North Atlantic Ocean. c. Warm air masses i. 4 masses influence warm weather in the summer/spring. 1. They are: a. Atlantic Ocean, Pacific Ocean, Gulf of Mexico, and the desert region of Mexico. 8. Fronts a. When 2 different air masses mix: i. A boundary is formed called a front. 9. Severe Weather a. Severe weather is weather that can cause property damage and even death. i. Thunderstorms 1. 2 conditions must exist to cause a thunderstorm. a. Air near the Earth’s surface must be warm and moist. b. The atmosphere must be unstable. i. This means that the air surrounding is colder than the rising air mass. (ie: the mixing of a warm and cold air mass) ii. Lightening iii. Severe Thunderstorms 1. Include hail storms a. Damage crops, automobiles, cause flash flooding. iv. Tornadoes 1. Comes from a cumulonimbus cloud. a. Starts as a funnel poking from the bottom of the cloud. b. It is called a tornado when it touches the ground. i. 75% of the worlds Tornadoes occur in the U.S. v. Hurricanes 1. Also called: a. Typhoons in the Western Pacific Ocean b. Cyclones in the Indian Ocean 2. Formation a. Begin over warm water as thunderstorms b. Gets energy from the warm water c. As the Hurricane moves over colder water or land, it begins to die. 3. Damage a. Winds b. Flooding c. See page 440-441 10. What is Climate a. Weather -vs- Climate i. Weather is the condition of the atmosphere at a particular time and place. ii. Climate is the average weather in a certain area over a long period of time. Standards 3a/3d 3a-Students know energy can be carried from one place to another by heat flow or by waves, including water, light and sound waves, or by moving objects. 3d-Students know heat energy is also transferred between objects by radiation (radiation can travel through space). p. 219-30, 398-401 1. What is Heat? a. Heat is the transfer of energy between objects that are at different temperatures. i. Energy is always transferred from a warmer area to a cooler area. (When running on the beach in bare feet, the energy is transferred from the hot sand to the bare skin). b. Thermal Energy i. The total kinetic energy of the particles that make up a substance. 1. An object with a high temperature has more thermal energy than the same sized object. (ie: When you hold an ice cube in your hand, the thermal energy from your hand is transferred to the ice cube, causing it to melt, increasing the thermal energy of the ice cube. At the same time, the thermal energy of your hand has decreased, making it feel cold). c. Thermal equilibrium i. Is when object of two different temperatures come in contact, and after transferring energy, have become the same temperature. 2. Methods of Heating a. Conduction i. Is the transfer of thermal energy through direct contact. (Remember the person walking on the beach with no shoes on)? ii. As fast moving particles collide 1. The thermal energy is transferred from the hot molecules to the cooler molecules. a. When a metal spoon is placed in hot soup, the handle of the metal spoon becomes hot, even though it is not actually in the soup. This is because the metal is a conductor of heat. Most metals are conductors. b. A wooden spoon would not have the same result as wood is an insulator, not a conductor. (See page 222) b. Radiation i. Is the transfer of thermal energy through space. 1. You can get warm from a heater just by standing near it. It is not necessary to actually touch the heater. 2. The Earth is warmed through radiation. a. The suns rays radiate through space, warming the Earth. c. Convection i. The rising and falling of warm air or liquid. (See standard 4a and 4d)