1 / 20

Unit 4 Lesson 1 Elements of Weather

Unit 4 Lesson 1 Elements of Weather. Unit 4 Lesson 1 Elements of Weather. Wonder About Weather?. What is weather?. Weather is the condition of Earth’s atmosphere at a certain time and place. Weather conditions in the atmosphere can be recognized through direct observation.

wylie
Télécharger la présentation

Unit 4 Lesson 1 Elements of Weather

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unit 4 Lesson 1 Elements of Weather

  2. Unit 4Lesson 1 Elements of Weather Wonder About Weather? What is weather? • Weatheris the condition of Earth’s atmosphere at a certain time and place. • Weather conditions in the atmosphere can be recognized through direct observation. • Weather is described by factors such as temperature, humidity, precipitation, air pressure, wind, and visibility.

  3. Unit 4Lesson 1 Elements of Weather What is temperature and how is it measured? • Temperature is a measure of how hot or cold something is (by the movement of the particles). An instrument that measures and displays temperature is called a thermometer. • Some thermometers use the thermal expansion of a liquid to determine temperature. • Electrical thermometers use the strength of an electric current to determine temperature.

  4. Unit 4Lesson 1 Elements of Weather What is humidity and how is it measured? • Humidityis the amount of water vapor in the air. As more water evaporates, humidity of the air increases. • Relative humidityis the amount of water vapor in the air compared to the amount of water vapor needed to reach saturation. It is measured with a psychrometer. • When air is saturated, the rates of evaporation and condensation are equal.

  5. Unit 4Lesson 1 Elements of Weather What is humidity and how is it measured? • Dew point is the temperature at which more condensation than evaporation occurs. • When air temperature drops below the dew point, water vapor condenses to form dew, fog, and clouds. • When an object’s temperature drops below the air surrounding it, dew will form on the object.

  6. Unit 4Lesson 1 Elements of Weather What is humidity and how is it measured? • Is the humidity in the air increasing or decreasing? Explain.

  7. Unit 4Lesson 1 Elements of Weather What is precipitation and how is it measured? • Precipitationis any form of water that falls to Earth’s surface from the clouds. It includes rain, snow, hail, and sleet. • Inside a cloud, water droplets can collide to form larger droplets, and when they become heavy enough, they fall as rain. • Rain is measured with a rain gauge.

  8. Unit 4Lesson 1 Elements of Weather What is precipitation and how is it measured? • Snow forms when air temperatures are low enough to turn water vapor into a solid. Fallen snow may be measured with a meterstick. • When balls or lumps of ice fall from clouds during thunderstorms, it is called hail. • Sleet forms when rain falls through a layer of freezing air, producing falling ice.

  9. Unit 4Lesson 1 Elements of Weather Watching Clouds • Cirrus clouds are made of ice and appear feathery or wispy. • Cumulus clouds appear as heaps or piles. They form in fair weather but can produce thunderstorms. • Stratus clouds form flat layers that can block out the sun and produce steady rain.

  10. Cumulus Clouds Cirrus Clouds Stratus Clouds

  11. Unit 4Lesson 1 Elements of Weather The Air Out There What is air pressure and how is it measured? • Airpressureis the force of air molecules pushing on an area. • A barometer is used to measure air pressure. • Air pressure and density decrease with altitude. • Air pressure and density will also increase with cooler air and decrease with warmer air.

  12. Unit 4Lesson 1 Elements of Weather What is air pressure and how is it measured? • Why do mountain climbers sometimes need extra oxygen to breathe at the top of a mountain?

  13. Unit 4Lesson 1 Elements of Weather What is wind and how is it measured? • Windis air that moves horizontally, or parallel to the ground. • Differences in air pressure sets air in motion. Over a short distances, air moves from higher pressure to lower pressure. This is felt as wind. • An anemometer is used to measure wind speed. • A wind vane or wind sock is used to measure wind direction.

  14. Unit 4Lesson 1 Elements of Weather What is visibility and how is it measured? • Visibilityis a measure of the distance at which an object or a light can be clearly seen. • Visibility is measured by using three to four known landmarks at different distances. • Air pollution or fog can cause poor visibility.

  15. Unit 4Lesson 1 Elements of Weather What are some ways to collect weather data? • Weather data can be collected at ground stations, by weather buoys, by ships, by airplanes, and by satellites.

More Related