Transcript Unit D
Unit D The Atmosphere and Beyond Chapter 10 Using Weather Data Lesson 1: What is Air? The Atmosphere Gases in the Air 1. Air is a mixture of colorless, odorless gases that surround the Earth. a. Nitrogen (78%) - Plants need nitrogen to grow. Plants absorb nitrogen through their roots. b. Oxygen (21%) - Living things need oxygen to survive. Your body needs oxygen to use the energy in their food. Most living things get their oxygen from the air. c. Carbon Dioxide, Water, and Other Gases (1%) - - Carbon Dioxide helps to hold heat close to the Earth. Humans and Animals give off Carbon Dioxide when they breathe. Plants use Carbon Dioxide to make their food. Earth’s Blanket 1. The Atmosphere is the layers of air that surround the air. a. The atmosphere holds the heat close to the Earth’s surface. b. The atmosphere helps protect living things from harmful rays given off by the sun 2. Air Pressure is the weight of air as it presses down on the Earth’s surface. a. The air particles are more spread out the higher up in the atmosphere you go. 3. The Atmosphere has Four Layers. a. Troposphere -This is where the earth’s weather occurs. -Weather is the conditions of the atmosphere at a certain place and time. b. Stratosphere c. Mesosphere d. Thermosphere Greenhouse Effect 1. The Greenhouse Effect is the process by which heat from the sun builds up near the earth’s surface and is trapped there by the atmosphere. Lesson 2: How Does the Water Cycle Affect Weather? Three States of Water 1. About three-fourths (75%) of Earth’s surface is covered by water. 2. Three forms of water. a. Liquid: oceans, seas, rivers, and rain b. Solid: ice forms when heat is removed from liquid water. c. Gas: water vapor forms when heat is added to liquid water. 3. How does water change forms? a. Evaporation is the change from a liquid form to a gas form. b. Condensation is the change from a gas form to a liquid form. The Water Cycle 1. The water cycle is the movement of water into the air as water vapor and back to Earth’s surface as precipitation. 2. Precipitation is any form of water that falls from the clouds to Earth’s surface. a. b. c. d. Rain- drops of water (most common) Sleet- rain that freezes as it falls Snow- water vapor in the clouds form ice crystals Hail- drops of rain freeze and strong winds carry them higher into a cloud. Hailstones fall again. Types of Clouds 1. Clouds form when water vapor in the air condenses. a. Status Clouds: low-level clouds that form in layers. (usually bring steady rain) b. Cumulus Clouds: fluffy with flat bases. (usually means fair weather) c. Cirrus Clouds: thin, feathery clouds that form high in the sky. (indicate fair weather) d. Cumulonimbus Clouds (bring thunderstorms) 2. A cloud that forms close to the ground is called fog. Lesson 3: What Causes Weather? Weather Factors 1. Temperature a. How hot or cold the air is. b. Air temperature is measured with a thermometer. c. Thermometer is a tube with liquid inside, as the air around the liquid gets warmer, the liquid gets warmer and expands or rises. d. Temperature is measured by degrees Celsius or Degrees Fahrenheit. 2. Water Vapor in the air a. Humidity is the amount of water vapor in the air. b. High humidity can make the air feel wet and sticky. c. Relative Humidity is the amount of water vapor the air is holding at a given temperature compared to the total amount that it can hold at that temperature. d. A Rain Gauge measures the amount of precipitation that fall to the Earth. 3. Air Pressure a. Air pressure is the weight of the air as it presses down on the Earth’s surface. b. Low-pressure area is a place where warm air rises and pushes down on the Earth’s surface with less pressure. c. High-pressure area is a place where cool air sinks and pushes down on the Earth’s surface with more pressure. d. A Barometer measures air pressure. 4. Wind a. Wind is the movement of air from a high pressure area to a low pressure area. b. Land heats and cools faster than water. -Sea Breeze: As warm air above the land rises cool air above the ocean moves in to take its place. -Land Breeze: As warm air above the ocean rises cool air above the land moves in to take its place. c. An Anemometer measures wind speed. d. A Wind Sock and Wind Vane (arrow points into the wind) measures wind direction. Air Masses 1. An Air Mass is a large body of air that has about the same temperature, air pressure and moisture throughout. 2. Air Masses are described by two conditionstemperature(cold and warm) and humidity(moist and dry). a. Where the air mass forms will tell the conditions of the air mass. -Example: poles are cold, equator are warm, land are dry, ocean are wet 3. Most changes in weather occur when one air mass moves into an area and pushes out another air mass. Weather Patterns 1. A front is the place where two air masses meet. a. Weather can change very suddenly when a front moves across an area. b. Cold Front forms as a cold air mass meets a warm air mass c. Warm Front forms as a warm air mass pushes into a cold air mass. Analyzing Weather Data 1. A meteorologist is a scientist who studies weather. a. Studying weather involves measuring conditions near the surface and high in the atmosphere. b. A forecast is a prediction of what the weather will be for a particular day, week, or longer period of time. Severe Weather 1. Severe weather includes hurricanes, tornadoes, and snowstorms. Lesson 4: How Does Climate Change? Climates of the World Major Climate Zones 1. Climate is the average weather conditions in an area over a long period of time. 2. Earth has three major climate zones. a. Tropical Climate is hot and rainy (North and South of the equator). b. Polar Climate has cold temperatures all year. c. Temperate Climate usually has warm, dry summers and cold, wet winters (middle zone).