Water in the Atmosphere Chapter 6 Section 1

Standard S 6.4 a 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.

Anticipatory Set Go Outside and try to identify the clouds you see outside. Take the map we created last week to help you. Have a discussion as to which stratosphere the clouds you see are located

Language of the Discipline Water Cycle Evaporation Humidity Relative humidity Psychomotor Condensation Dew point Cirrus Cumulus Stratus

Water in the Atmosphere Water cycle is the continuous movement of water between the atmosphere and Earth’s surface Sun’s energy is the power to the water cycle Has no real beginning or end Water vapor is added to the air by living things Plant roots, leaves and releases it as water vapor

Humidity The measure of the amount of water vapor in the air Relative Humidity The percent of water vapor that is actually in the air compared to the amount of water vapor the air can hold at a specific temperature Relative humidity can be measured with an instrument called a psychomotor. Psychrometer wet bulb/dry bulb thermometer

How Clouds Form Clouds form when water vapor in the air condense to form liquid water or ice crystals. Role of Cooling Cold air holds less water vapor As air cools, it holds less and forms tiny drops of water Dew point- temperature at which condensation begins If dew point is below freezing then it changes into ice crystals.

Particles For water vapor to condense, tiny particles must be present so the water has a surface on which to condense Blades of grass Window panes Dew Can you thing of anything else that has dew on it?

Types of Clouds Cirrus- Wispy, feathery clouds (like the curl of a hair) Made of ice crystals Looks like rows of cotton balls Indicates a storm is on it’s way Looks like scales of fish

Cumulus Clouds Fluffy, round piles of cotton Heap or mass of clouds Not very tall Indicate Common on sunny days

Stratus Clouds Spread out clouds Covers all or most of the sky Uniform dull, gray in color As they thicken, they produce rain, drizzle or snow

Clouds Part of a clouds name is based on it’s height Altocumulus Altostratus “Middle level” clouds Alto- “high”

Fog Clouds that form at or near the ground When the ground cools at night after a warm day Heat from the next day “burns” the fog off and it evaporates Common near bodies of water or marshy areas

Checking for Understanding What instrument measures relative humidity? What 2 factors are required for condensation to occur? What are stratus clouds?

Guided Practice Independent Practice Worksheet # 1-5 for Guided Practice Stop! Have work checked Independent Practice Workbook pages