Weather and the Water Cycle Chapter 11 Lesson 1: What Causes Weather? Lesson 2: What Conditions Affect the Water Cycle ? Lesson 3: How Can patterns in Weather Be Observed?

Lesson 1: VOCABULARY Atmosphere: the blanket of air surrounding Earth. Troposphere: the layer of air closest to Earth’s surface. Air Pressure: weight of the atmosphere pressing down on Earth. Local Winds: movements of air that result from local changes in temperature. Prevailing wind: Global winds that blow constantly from the same direction

Lesson 1: The Atmosphere If Earth were the size of a peach, the atmosphere would be thinner than the peach’s fuzz. The troposphere contains about 90% of the gases in the atmosphere. The stratosphere contains most of the Earth’s ozone. Ozone is a gas that protects Earth from the sun’s ultraviolet rays Cold air is more dense than warm air, so it is heavier than warm air

Lesson 1: Uneven Heating The air around you is always moving and changing When the sun’s energy reaches Earth, some of the energy bounces off objects. Different types of surfaces absorb or reflect this energy Example- Sand on a beach is much hotter than the water near the sand Because of this, the air over the beach will be hotter, too. The air over the water-cooler

Lesson 1: Local Winds/Prevailing Winds Wind results from air moving from areas of high air pressure to areas of low pressure Local winds often occur on lakeshores or seashores Wind that always blow in the same direction is a prevailing wind Uneven heating of large areas of Earth’s surface cause these

Lesson 2: Vocabulary Water Cycle- process in which water continuously moves from Earth’s surface into the atmosphere and back again Evaporation- process of a liquid changing into a gas Condensation- process of a gas changing into a liquid Humidity- measurement of the amount of water vapor in the air Precipitation- Water that falls from the air to Earth

Lesson 2: What Conditions Affect the Water Cycle? The Water Cycle is important because: People plants, and animals need fresh water to live. Without rain and snow, we wouldn’t have drinking water. We also would not have water to grow crops for feeding. It constantly recycles water in lakes, rivers, streams, and oceans. It keeps groundwater flowing, which is water underground.

Lesson 2: Clouds and Precipitation? A large part of the water cycle occurs in the atmosphere The more water vapor in the air, the more humid the air is. Warm air usually have more water vapor in it that cold air does As more and more water condenses, a cloud forms A cloud is basically dust and condensed water. When water droplets inside a cloud are too heavy to stay up they fall to the Earth as. Rain Snow Sleet Hail

Lesson 2: Factors that Affect the Water Cycle? How close a place is to Earth’s poles or the equator. The shape of the land Landforms and Temperature

Lesson 3: Vocabulary Air Mass- A large body of air that has similar temperature and humidity throughout. Front- The border where two air masses meet. Climate- The Pattern of weather an area experiences over long period of time.

Lesson 3: How Can Patterns in Weather Be Observed? Measuring Weather: Because there are many different kinds of weather data, you need many different instruments A thermometer measures air temperature. A hygrometer measures humidity (amount of water in air) A barometer measures air pressure An anemometer measures wind speed A Doppler Radar gives a view of the weather from above

Lesson 3: Air Masses and Fronts Air masses can be warm or cold, humid or dry: they take on characteristics of the region over which it forms When the weather changes in an area, it means that the air mass over the area is changing too.

Lesson 3: Fronts The border where two air masses meet is called a front Most weather changes occur along a front There are two main kinds of fronts cold and warm: When warm fronts get pushed up by cold fronts, heavy rain and thunderstorms occur

Lesson 3: Weather Patterns and Climates Weather in most locations occur in regular patterns: In addition to wind patterns, there are temperature patterns Over a long time, there are seasonal patterns Like daily patterns, seasonal weather patterns are driven by the sun

Lesson 3: Landforms Affect Climate Mountains affect the water cycle by forcing air to rise and cool -This causes rain or snow on the side of the mountain to faces the wind -As air sinks, its humidity goes down even more. Oceans can also affect an area’s climate -land near a large body of water tends to have a milder climate than other areas. -This land is usually cooler in summer, warmer in winter, and more humid all year than areas farther inland