Weather Factors Chapter 12 SOL 6.3

Energy from the sun travels in electromagnetic waves. Energy from the sun travels in electromagnetic waves. Radiation= the direct transfer of energy by electromagnetic waves. Radiation= the direct transfer of energy by electromagnetic waves. Most of the energy from the sun reaches Earth in the form of visible light and infrared radiation. A small amount is ultraviolet radiation. Most of the energy from the sun reaches Earth in the form of visible light and infrared radiation. A small amount is ultraviolet radiation. CFU: How does energy from the Sun reach Earth? CFU: How does energy from the Sun reach Earth?

Electromagnetic waves are classified according to wavelength or the distance between waves. Infrared radiation= longer wavelengths, not visible, can be felt as heat. Visible Light = a mixture of all colors. UV radiation= shorter wavelengths, cause sunburns and eye damage. CFU: What has the shorter and longer wavelengths from the information above?

Some of the energy from the sun is absorbed within the atmosphere.  Water vapor and carbon dioxide absorb some infrared.  The ozone layer absorbs most UV radiation.  Clouds, dust and other gases also absorb energy.  CFU: What absorbs most ultraviolet radiation from the Sun?

Some of the sun's rays are reflected by clouds, dust, and other particles in the atmosphere. Some of the sun's rays are reflected by clouds, dust, and other particles in the atmosphere.  Reflection of light in all directions is called scattering and it causes the sky to look blue.  When the sun rises or sets, the sunlight is passing through a thicker layer of atmosphere. CFU: What causes the sky to look blue?

Some of the sun's energy is absorbed by the land and water and changed into heat. Different surfaces are affected by the sun's energy differently. Different surfaces are affected by the sun's energy differently.  dark colored material absorbs more energy  water takes more energy to heat (think specific heat!) After the Earth is heated, some of the energy returns to the atmosphere. The gases in the atmosphere form a blanket around Earth that holds in heat. This is called the greenhouse effect. CFU: Explain the Greenhouse Effect.

Temperature is one of the most important elements of weather and is measured with a thermometer.

Heat is transferred in three ways: radiation, conduction and convection. radiation= through space (ex. Sun on face) radiation= through space (ex. Sun on face) conduction= through touch (ex. Walking on hot sand) conduction= through touch (ex. Walking on hot sand) convection= through fluid (liquids/gases) (ex. Warm breeze) convection= through fluid (liquids/gases) (ex. Warm breeze) CFU: Give an example of conduction. CFU: Give an example of conduction.

The troposphere depends on convection for most of its heating. When air near the ground is heated, the molecules move faster and bump into one another which circulates heat. CFU: What does the layer we’re in depend on for most of its heating?

Wind= the horizontal movement of air from an area of high pressure to an area of lower pressure. All winds are caused by differences in air pressure. All winds are caused by differences in air pressure. Differences in air pressure are caused by unequal heating of Earth's surface. Differences in air pressure are caused by unequal heating of Earth's surface. Local winds are caused by unequal heating of Earth's surface within a small area. Local winds are caused by unequal heating of Earth's surface within a small area. The movement of air between the equator and the poles produces global winds. The movement of air between the equator and the poles produces global winds. CFU: In what direction does air (wind) always move from one place to another?

The way Earth's rotation makes winds curve is called the Coriolis Effect.

 Nimbo/Nimbus= rain or bad weather  Transpiration= evaporation from the leaves of plants

“It's not the heat, it's the HUMIDITY!!!” Humidity= the measure of the amount of water vapor in the air. Humidity= the measure of the amount of water vapor in the air. Relative humidity= the percentage of water vapor in the air compared to the maximum amount the air could hold. Relative humidity= the percentage of water vapor in the air compared to the maximum amount the air could hold.  A psychrometer is used to measure relative humidity.  When the relative humidity is high, evaporation slows down. This makes you feel hotter. CFU: What makes us feel even hotter on a hot day?

Clouds of all kinds form when water vapor in the air becomes liquid water or ice crystals through the process of condensation.  Cold air holds less water vapor than warm air.  The temperature at which condensation begins is called the dew point. CFU: What process causes clouds?

Meteorologists classify clouds into 3 main types: cumulus, stratus, and cirrus. Cumulus= look like fluffy rounded piles of cotton; often mean fair weather Cumulus= look like fluffy rounded piles of cotton; often mean fair weather  Cumulonimbus often produce thunderstorms Stratus= form in flat layers; usually cover all or most of the sky Stratus= form in flat layers; usually cover all or most of the sky  Nimbostratus clouds are thicker and often produce drizzle, rain or snow. Cirrus= wispy, feathery clouds that form at high levels; made of ice crystals. Cirrus= wispy, feathery clouds that form at high levels; made of ice crystals. CFU: What are the three main type of clouds?

Fog=clouds that form at or near the ground.

Precipitation is any form of water that falls from clouds and reaches Earth's surface. Precipitation is any form of water that falls from clouds and reaches Earth's surface.  Always comes from clouds and may fall as rain, sleet, freezing rain, hail or snow.  Cloud droplets or ice crystals must grow heavy enough to fall through the air. (They collide and combine with other droplets.) CFU: What are some different types of precipitation?

Types of Precipitation Rain= most common Rain= most common Sleet=freeze as they fall Sleet=freeze as they fall Freezing rain= freezes when it touches a cold surface Freezing rain= freezes when it touches a cold surface Hail= falls during thunderstorms, formed in clouds Hail= falls during thunderstorms, formed in clouds Snow=water vapor converted to ice crystals in a cloud Snow=water vapor converted to ice crystals in a cloud

Meteorologists measure rainfall with a rain gauge. Snow fall is measured with a ruler. Meteorologists measure rainfall with a rain gauge. Snow fall is measured with a ruler.

Droughts are long periods of unusually low precipitation and they can cause great hardship such as loss of income for farmers and widespread hunger or famine. Droughts are long periods of unusually low precipitation and they can cause great hardship such as loss of income for farmers and widespread hunger or famine.  Scientists are experimenting with cloud seeding to produce rain in areas experiencing drought and to clear fog from airports.