Transcript Do NOW
Water, Water Everywhere AIM: What is the hydrologic cycle? Water Cycle (hydrologic cycle) Water enters the atmosphere… ► Evaporation – Water changes from a liquid to a gas. Most water evaporates from the oceans. Latent heat is stored. Wind and high temps speed up evaporation. ► Transpiration – water in plants evaporates ► Evapotranspiration – all evaporation from earth and plants. Water leaves the atmosphere… ► Condensation – Water changes from a gas to liquid to form clouds. Latent heat is released. ► Precipitation – any form of water that falls from clouds (rain, snow, sleet, hail) Where does it go? ► Runoff –water that flows over the ground, eventually leads back to a larger body of water ► Accumulation – when water collects into large bodies, or falls directly into it Where does it go? ► Infiltration – when water seeps (sinks) into the ground to be stored as groundwater ► Groundwater flow – when water moves while underground Factors that affect infiltration ► 1. Porosity: the size of the spaces between sediments in the ground or in the rocks themselves. ► 2. Permeability: how fast water will pass through the soil material. The ability to pass through sediments in the ground. Permeability: ►Permeable: water passes through fast (gravel and sand) ►Impermeable: water passes through very slowly (silt and clay) Permeability animation Why did the water pass through the gravel and sand faster? Gravel and Sand: High porosity, high permeability Because there are larger spaces between the pieces of gravel and grains of sand where water can go through easily. Silt and Clay: Low porosity, low permeability Silt and clay are tightly packed together and have very small spaces between them. What is the relationship between sediment size and porosity? ► The larger the sediment, the more porous because the spaces will be bigger. ► The smaller the sediment, the less porous because the spaces will be smaller. http://www.brainpop.com/science/earthsystem/groundwater/ Factors that affect runoff: ► Permeability ► Slope of the soil- type of soil – steeper will cause more runoff ► Saturation of the ground – wetter ground will decrease permeability and cause more to run off ► Groundcover – vegetation decreases runoff, concrete increases runoff. Fill it in… http://www.brainpop.com/science/earthsystem/watercycle/ Do NOW ► 1. ► 2. ► 3. ► 4. ► 5. AIM: How do we measure water vapor in the air? How much water is in the air? ► Relative humidity –% of water vapor in the air compared to the max it can hold ► Example: If the air is half filled to its capacity, it’s relative humidity is 50%. ►A basic rule is that warm air holds more moisture than cool air How much water can the air “hold” before it rains? ► Dew point – the temperature that the air needs to reach for precipitation to happen, it’s the point that condensation occurs ► Example: Air temp = 75o Dew Point = 75o Relative humidity = 100% and it is raining! How does relative humidity change with air temperature? ► Air at different temperatures will hold more or less amounts of water vapor. ► Warm air can hold more water vapor before it is saturated than cold air. ► www.weather.com Measuring relative humidity ► Psychrometer of hygrometer ► Has – a type 2 thermometers: A Dry bulb thermometer A Wet bulb thermometer covered in damp cloth (evaporation causes cooling) Example #1 ► What are the relative humidity and dew points? ► Wet bulb temp = 12oC ► Dry bulb temp = 16oC ► Wet bulb depression = 16 - 12 = 4oC Example #2 ► If the dew point is 10oC, and the air temperature is 20oC, what is the wet bulb temperature? Example #3 ► If the relative humidity is 90%, and the difference in the dry and wet bulb is 1oC, what is the dry bulb temperature? Mini Lab ► Wet bulb = thermometer with cloth ► Dry bulb = thermometer kept dry ► 2 minutes of fanning ► Record temperatures ► Find relative humidity and dew point using chart ► Answer all questions Brainpop - humidity ► http://www.brainpop.com/science/weather/humidity/ Do NOW What 2. What 3. What 4. What 1. are clouds? is fog? is dew? is frost? ► AIM: What does condensation do ? Water Cycle Movie Water Cycle Movie The EPA Global Warming Kids Page--Water Cycle Animation Why do clouds form? ► Clouds air. exist in the atmosphere because of rising ► As air rises and cools the water in it will release heat and turn to liquid or ice crystals forming clouds. (condensation) ► Tiny particles of dust, salt, and smoke in the air are needed for the water to condense onto. What do clouds do? ► Clouds influence the Earth's climate: Reflect incoming solar radiation back to space Block outgoing heat from the Earth's surface. At night, clouds act as a "blanket," keeping some of the day's heat near the surface. Carry moisture around the globe as part of the water cycle What are the different types of clouds? ► There are three basic types: Stratus – spread out in flat layers Cumulous – fluffy piles of cotton Cirrus – wispy feathery clouds made of ice crystals When you add the suffix nimbus to a cloud type it means “rain” Guess what kind of cloud it is… Look out the window… ► What kind of clouds do you see today? ► What is the weather expected today? ► Is there a lot of moisture in the air or a little? What are man-made clouds? ► Contrails are the condensation trail that is left behind by a passing jet plane. Contrails form when hot moist air from jet exhaust mixes with the cold air in the high altitudes. What is fog? ► Fog happens when a stratus cloud forms near the ground. When warmer air passes over cooler ground. ► Observe images of advection fog. ► Cloud matching game Brainpop - clouds ► http://www.brainpop.com/science/weather/ clouds/ Levels of Clouds ► Low clouds – made of water droplets Ex. Cumulus Levels of Clouds ► High clouds – made of ice crystals Ex. Cirrus Condensation… ► Dew point – the temperature at which condensation occurs ► Water vapor in air cools and condenses and turns to liquid droplets…clouds! Lenticular Clouds