Big Idea 7: Earth Systems and Patterns Description The scientific theory of the evolution of Earth states that changes in our planet are driven by the flow of energy and the cycling of matter through dynamic interactions among the atmosphere, hydrosphere, cryosphere, geosphere, and biosphere, and the resources used to sustain human civilization on Earth. Benchmark Number &Descriptor • • • • • • • • SC.6.E.7.1 Differentiate among radiation, conduction, and convection, the three mechanisms by which heat is transferred through Earth's system. SC.6.E.7.2 Investigate and apply how the cycling of water between the atmosphere and hydrosphere has an effect on weather patterns and climate. SC.6.E.7.3 Describe how global patterns such as the jet stream and ocean currents influence local weather in measurable terms such as temperature, air pressure, wind direction and speed, and humidity and precipitation. SC.6.E.7.4 Differentiate and show interactions among the geosphere, hydrosphere, cryosphere, atmosphere, and biosphere. • • • • • • • • • • SC.6.E.7.5 Explain how energy provided by the sun influences global patterns of atmospheric movement and the temperature differences between air, water, and land. SC.6.E.7.6 Differentiate between weather and climate. SC.6.E.7.7 Investigate how natural disasters have affected human life in Florida. SC.6.E.7.8 Describe ways human beings protect themselves from hazardous weather and sun exposure. SC.6.E.7.9 Describe how the composition and structure of the atmosphere protects life and insulates the planet. EARTH’S SPHERES ATMOSPHERE • A gaseous sphere surrounding the Earth • Consists of 4 layers: – Troposphere: layer in which we live; weather occurs; clouds form. – Stratosphere: solar radiation; temperature increases; ozone layer is found – Mesosphere: coldest layer in atmosphere – Thermosphere: Furthest away from Earth; helps absorb radiation ATMOSPHERE • Energy: – Sun is the source for 99% of heat energy on Earth. • 25% - reflected by atmosphere • 5% - reflected by ice and snow • 25% - absorbed by atmosphere • 45% - absorbed by Earth’s surface • Energy Transfer – Energy is transferred 3 ways (see Big Idea 11-7 th grade for more information) • Conduction – particles must touch to transfer energy. • Convection particles circulate to transfer energy. • Radiation – energy travels in the form of waves. – Example: Greenhouse Effect “WATER, WATER, EVERYWHERE” HYDROSPHERE • Includes all of the water on Earth found in streams, lakes, the soil, groundwater, and the air • 71% of the Earth is covered by water. – Salt water = 97% (oceans) – Fresh water = 2.8% (icecaps, glaciers, lakes, streams, groundwater) CRYOSPHERE • Part of the Earth's hydrosphere comprised of frozen water • The cyrosphere is a sensitive element of the climate system providing a key indicator of climate change. Water regulates the temperature on Earth. The Water Cycle • Water on Earth is recycled through the Water Cycle. • The Water Cycle consists of the following activities: – Evaporation – Condensation – Precipitation – Percolation – Runoff – Transpiration The Water Cycle • A water cycle is the way water moves from the air to land and back. Condensation • The water vapor rises into the air, cools, and condenses into tiny droplets of water. • The drops of water come together to form clouds. Water Cycle Evaporation is when a liquid changes to a gas. The sun’s heat makes water evaporate into water vapor. Precipitation The water drops become heavy and fall as rain, sleet, snow, or hail. The rain falls or snow melts and flows to rivers, lakes, and oceans. WHY THE WATER CYCLE IS IMPORTANT LITHOSPHERE • The Earth's solid surface, often called the crust of the Earth. • Included are: continental and oceanic crust as well as the various layers of the Earth's interior BIOSPHERE • Contains all life on Earth, including human, and all organisms • The biosphere extends to any place that life (of any kind) can exist on Earth. • This layer relies on a continuous supply of energy from the sun. • Contains the factors needed for life: – Water – Moderate temperature – Food source • Energy is in constant flow throughout the Biosphere. – Animals/plants break down and decompose. – Elements such as carbon dioxide and nitrogen are released. – Resources are used over again – Carbon/Nitrogen Cycles. CARBON CYCLE • Every living thing contains carbon. • Importance: – Photosynthesis – uses carbon dioxide and gives off oxygen (producers). – Respiration – uses oxygen and gives off carbon dioxide (consumers). NITROGEN CYCLE • Nitrogen is found in our atmosphere. • It provides soil with nutrients. • Plants and animals use nitrogen. • When plants/animals decompose in/on the ground, nitrogen seeps in creating fertile soil. SPHERE RECAP – Lithosphere - All processes associated with the solid earth – Hydrosphere - All processes associated with water – Atmosphere - All processes associated with the gases that envelope the earth – Biosphere - All processes that involve living organisms • If a change in a sphere happens, a chain reaction could take place in Earth’s Cycles • Earth’s Cycles include: – Water – Carbon – Nitrogen KNOWLEDGE CHECK 1. Name 4 Earth’s spheres. 2. How is energy transferred throughout the atmosphere? 3. What two cycles occur in the Biosphere? KNOWLEDGE CHECK 1. Name 3 of Earth’s spheres. Atmosphere, Hydrosphere, Biosphere, Lithosphere 2. How is energy transferred throughout the atmosphere? Conduction, Convection, Radiation 3. What two cycles occur in the Biosphere? Carbon cycle, Nitrogen cycle CLIMATE and WEATHER What Causes Climate? • Overall/average temperature and precipitation for an area • Climate is determined by two basic factors: – temperature – precipitation CLIMATE FATORS PRECIPITATION TEMPERATURE • Average KE of molecules – High Temperature= increase movement of molecules= feels hot – Low Temperature= decrease movement of molecules= feels cold • When a droplet reaches a certain critical mass, the force of gravity will exceed the other making precipitation fall. • Types of precipitation: – – – – Rain Snow Sleet Hail Climate Zones • The Earth’s climate can be divided into 3 climate zones. – Based on average temperatures • 3 major climate zones on the Earth – Polar – Temperate – Tropical zones. POLAR CLIMATES • The average yearly temperature is below freezing. • Even during the warmest months of the year, the temperature does not go over 10°C TEMPERATE CLIMATE • Located between the tropics and the polar tropics • Generally contains four seasons • Climate can be broken down into four categories: – Oceanic – Mediterranean – Humid subtropical – Continental World map with temperate zones highlighted in red. TROPICAL CLIMATE • • • • Cover the largest area of Earth Experience hot and humid weather Much rainfall Seasons are defined by precipitation. CLIMATE OVER TIME • There are three natural factors responsible for climate change over time: 1. Slow drifting of the continents 2. Changes in the sun’s energy output 3. Variations in the position of the Earth relative to the sun • Changes related to human activity 1. Burning of fossil fuels A petrochemical refinery in Grangemouth, Scotland, UK KNOWLEDGE CHECK 1. What determines the overall climate of a specific area? 2. How many major climate zones are located in the world? 3. List 3 factors that contribute to climate change. KNOWLEDGE CHECK 1. What determines the overall climate of a specific area? Temperature and precipitation 2. How many major climate zones are located in the world? 3 major climate zones 3. List 3 factors that contribute to climate change. Changes in the sun’s energy. Changes in the location relative to the sun. Burning of fossil fuels. WHAT IS WEATHER? • The current state of the atmosphere ...what is happening right now. KEY IDEAS ABOUT WEATHER • The sun warms the Earth’s surface and all the air above the surface. • Earth’s highest temperatures are at the equator and the coldest at the poles. • The air above land is warmed more quickly than air above water. • Warm air expands and rises, creating an area of low pressure; cold air is dense and sinks, creating an area of high pressure. TODAY THE WEATHER IS… • Conditions that affect weather: –Temperature –Pressure –Moisture content –Winds TEMPERATURE • Three natural factors that affect the temperature of a particular location: – Latitude – Elevation – Presence of ocean and land • Warm air is light - rises up. • Cold air is heavy – sinks. TEMPERATURE Latitude Elevation • Latitude is the measurement of a specific location on Earth relative to its equator. • The further away from the equator the less sunlight that this location receives. • Since air is "clear," sunlight passes through it easily and heats the ground. • The atmosphere then gets heated from the ground, and the atmosphere is warmer near the ground. • As warm air rises from the ground, it expands and cools. – Colder temperature – result = colder air at higher altitudes than at the surface TEMPERATURE Land • Organic materials such as plants and animals tend to absorb energy. – Air temperature in a forest is usually cooler than the temperature in a desert. • Desert area tends to reflect energy. – Air temperature can be raised by as much as 10 degrees. Ocean • Water absorbs vast amounts of energy from the sun. Likewise, bodies of water release energy very slowly. For this reason, areas near water are usually more mild. • Because of water’s ability to absorb heat, store it, and release it later, the Earth’s oceans have an important role in helping to moderate its temperature. KNOWLEDGE CHECK 1. What is the difference between weather and climate? 2. What are the four factors that influence weather? 3. How does elevation and latitude affect temperature? 4. How does the temperature of land differ from the oceans? KNOWLEDGE CHECK 1. 2. 3. 4. What is the difference between weather and climate? Climate is an overall figure whereas weather is what is happening immediately. What are the four factors that influence weather? Temperature, pressure, moisture, wind How does elevation and latitude affect temperature? Latitude determines how much sunlight an area receives; elevation relates to how much the air cools before it reaches an area. How does the temperature of land differ from the oceans? Land: more vegetation/obstacles the lower the temperature (absorbs energy) Water: absorbs a lot of energy from the sun and helps regulate the Earth’s temperature. UNDER PRESSURE AIR PRESSURE • Caused by the weight of all the air in the atmosphere pressing down on Earth • Air pressure changes with: – Altitude – Temperature of air • Change in pressure = change in weather • Air Pressure is measured in millibars (mb) on a barometer. • The simplest kind of barometer is a mercury barometer, and pressure is measured in mm in/of mercury. • LOW PRESSURE • Warm surface conditions produce low pressure near the surface. • Warm air is buoyant & light, having the tendency to rise, causing surface pressure to fall • Lows are areas of low pressure with the lowest pressure at the center. • Lows usually bring wet, cloudy weather. HIGH PRESSURE • Cold surface conditions produce high pressure near the surface. • Cold air is heavy & dense and has a tendency to sink, causing surface pressure to rise. • Highs are areas of high pressure with the highest pressure at the center. • Highs bring sunnier and dry weather. KNOWLEDGE CHECK 1. What is air pressure? 2. Describe the difference between an area of high and low pressure. KNOWLEDGE CHECK 1. What is air pressure? The weight of the air pressing down on Earth’s surface 2. Describe the difference between an area of high and low pressure. Low Pressure: Warm air rises leaving causing pressure to fall; wet weather High Pressure: Cold air sinks causing pressure to increase; dry weather MOISTURE in the AIR HUMIDITY • The amount of water vapor in the air • The maximum quantity of moisture that can be held in the air depends on air temperature. Relative humidity changes when: 1. Atmosphere gains or loses water vapor. • Evaporation 2. Temperature changes. • Lower temperature relative humidity rises • Raise temperature relative humidity decreases Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Humidity and Humans • The higher the humidity rate, the more uncomfortable we feel. – The air is saturated, and therefore sweat will not evaporate off your body. PRECIPITATION • Precipitation is the release of water from the atmosphere to the Earth’s surface as a solid or liquid. – – – – Rain Snow Hail Seet • In order for precipitation to be created, air must move upward and become colder. • The type of precipitate which hits the ground depends on the temperature in the lower part of the atmosphere. Precipitation in the United States Types of Precipitate RAIN SNOW • Rain starts when small droplets of water in the clouds join together until they get too big and heavy. • Eventually, these droplets fall from the clouds and hit Earth’s surface. • Clouds involved: • Snow starts the same way as rain with tiny droplets of water joining together in clouds until they are too heavy. • When the droplets fall, it is important that the air is at a freezing temperature for snow to form. – Cumulonimbus – heavy rainfall – Stratus - drizzle Types of Precipitate HAIL SLEET • Hail begins as tiny ice pellets that collide with water droplets. • Formed in cumulonimbus clouds • Both gravity and downdraft thunderstorm winds pull the pellets to Earth’s surface. • Ice pellets are similar to hail but smaller and more likely to occur in winter • In winter states, people refer to sleet as rain mixed with snow that melts as it falls. • Rain passes through a layer of clouds with freezing temperatures. KNOWLEDGE CHECK 1. What is humidity, and what factor affects it? 2. How does humidity affect humans? 3. List 4 types of precipitation. 4. List 2 factors that are needed in order for precipitation to occur. KNOWLEDGE CHECK 1. What is humidity, and what factor affects it? Amount of water vapor in the air, depends on temperature. 2. How does humidity affect humans? The more humid it is, the less sweat does not evaporate from the body leaving a person hot and very sweaty. 3. List 4 types of precipitation. Rain, Snow, Sleet, Hail 4. List 2 factors that are needed in order for precipitation to occur. Air must move upward and become cooled, the temperature of the air close to the ground will determine what type of precipitation will occur. WINDS WHAT IS WIND? • When there is a difference in air pressure in the atmosphere, wind is created. – Unequal heating causes changes in air pressure. • Wind always moves from areas of high pressure to areas of low pressure. THE JET STREAM • Fast flowing, narrow air currents found in the atmospheres between the troposphere and the stratosphere • Caused by heating of the Earth and its rotation • These winds flow from west to east around the world. Jet streams flow from west to east in the upper portion of the troposphere. GLOBAL WIND DIRECTION • Coriolis Effect – Rotation of the Earth causes moving air and water to change directions. • Northern Hemisphere winds curve to the right. • Southern Hemisphere winds curve to the left. WIND SPEED • Result in a large pressure difference • Strong winds also occur in low latitudes due to stronger heating and greater pressure differences. – Hurricanes and tornadoes are examples. KNOWLEDGE CHECK 1. What must be different for wind to occur? 2. What is the Jet Stream? 3. What helps move winds around the globe? 4. What factor determines wind speed? KNOWLEDGE CHECK 1. What must be different for wind to occur? Air pressure 2. What is the Jet Stream? Fast flowing, narrow air currents found in the atmospheres 3. What helps move winds around the globe? Coriolis Effect 4. What factor determines wind speed? large pressure difference HOW DO WE PROTECT OURSELVES? HAZARDOUS WEATHER of FLORIDA LIGHTNING • • • • Lightning is an electric current. Cloud fills with electrical charges – Positive charges on top of cloud – Negative charges on the bottom of cloud Ground on the Earth contains electrical charge. Tall objects help carry these charges towards the air. Eventually the charges from the ground connect with a charge reaching down from the clouds and - zap - lightning strikes! • ** Tampa is considered the Lightning Capital of North America THUNDERSTORMS • • • • Generates lightning and thunder Storms form when warm humid air rises in an unstable area. Severe thunderstorm can have winds traveling at 80 kilometers per hour and hail more than 2 centimeters in diameter. Thunderstorms can also cause: – Flash flooding – Strong winds – Hail – Tornadoes HAZARDOUS WEATHER of FLORIDA TORNADO • Develop from severe thunderstorms • Characterized by a funnel cloud moving over land – Known as water spouts when moving over water • 200 m in diameter (20 classrooms long) • Generally lasts less than 10 minutes HURRICANES • Largest storm that occurs on Earth • Classified as a low pressure system that forms over tropical oceans • May go on for days • Weakens when hits cool water or strikes land • Florida has had over 488 tropical storms/hurricanes. PROTECT YOURSELF FROM SEVERE WEATHER FROM THE SUN • Wear sun block • Get you vehicle windows tinted. • When exercising or working outside, cover up • When walking outside. use an umbrella. http://www.fema.gov/kids/ • • • THUNDERSTORM: When a storm is coming, look for darkening skies, flashes of light ,or increasing wind. Listen for the sound of thunder. If you can hear thunder, you are close enough to the storm to be struck by lightning. Go to safe shelter immediately. HURRICANE: Listen to a radio or television for weather updates, and stay in touch with your neighbors about evacuation orders. Assemble your disaster supplies kit. Store extra water now! Check to make sure you have enough food. TORNADO: Listen to a radio. or watch television for weather updates. If a tornado is coming, you MUST seek shelter. An underground shelter is best, such as a basement or storm shelter. If you don’t have a basement, find an inside room or hallway or closet on the first floor AWAY FROM WINDOWS. KNOWLEDGE CHECK 1. What are four common hazardous weather conditions common in Florida? 2. Since the sun’s rays are strong in the state of Florida, list two ways to help protect yourself. 3. What is one common safety measure to take amongst any severe weather threats? KNOWLEDGE CHECK 1. What are four common hazardous weather conditions common in Florida? Lightning, thunderstorms, tornados, hurricanes 2. Since the suns rays are strong in the state of Florida, list two ways to help protect yourself. Wear sunscreen; stay covered up. 3. What is one common safety measure to take amongst any severe weather threats? Listen to a radio, or watch television for weather updates; have a plan.