Chapter 5 Lesson 1: Air and Weather EQ: Where does weather take place? How are tools helpful to scientists when predicting weather?

Air surrounds Earth like a thin blanket Air surrounds Earth like a thin blanket. This blanket is called the atmosphere. The atmosphere is made up of different gases. Most of the air is made up of nitrogen and oxygen. There are other gases such as carbon dioxide and water vapor too. Without these gases, life couldn’t exist on Earth. What is in the air?

Earth’s atmosphere is made up of layers Earth’s atmosphere is made up of layers. The layer closest to Earth is the troposphere. The troposphere is where all of Earth’s weather takes place. The air is always on the move from place to place called wind. Any change in the wind brings a change in the weather. Troposphere

Layers of the Atmosphere Click Me!

Other Layers of the Atmosphere Stratosphere: the layer above the troposphere. This is where temperatures get warmer as you go higher Temperatures get colder in the Mesosphere and Thermosphere. Other Layers of the Atmosphere

What are some properties of weather? Air temperature Humidity Air pressure Precipitation Weather is the condition of the atmosphere at a given time and place. What are some properties of weather?

Air temperature affects the speed and direction of the wind. When the Sun’s energy heats Earth’s surface the temperature goes up. If the air temperature changes, the air moves and winds blow. Air Temperature

If the air around us feels damp and sticky, we say it is humid. Humidity measures how much water vapor is in the air. Air always has some amount of water vapor in it. Most of the gas comes ocean water that has evaporated and this is why air is more humid over oceans and lakes. Humidity Click Me!

We live at the bottom of the Troposphere and all of the weight of the entire atmosphere pushes down on us. The force pushing down on an area is called air pressure. Cool air particles are closer together than particles of warm air. Air that weighs more has greater air pressure. For that reason, cool air has higher air pressure than warm air. Air Pressure

Precipitation is any form of water that falls from the clouds. This includes: hail, snow, sleet, and rain. The amount of precipitation is an important property of weather. Precipitation

How can you measure weather? To gather weather data, scientists observe and measure different properties of the air. They need certain instruments to do this. A weather station is a place where scientists keep theses tools.

Thermometers measure temperature-how hot or cold something is. A weather thermometer measures the temperature of air. Scientists use weather thermometers indoors and outdoors. Thermometers

Wind Vanes A wind vane shows the direction of the wind. All wind vanes have an arrow. The arrow points in the direction from which the wind is blowing. A wind sock also shows the direction of the wind. Wind Vanes

Rain Gauge A rain gauge measures the amount of rain fall. The simplest kind is a tube with markings on the side. As rain falls, it collects inside the tube. The markings show how much rain fell. Rain Gauge

Barometer A barometer measures air pressure. Some are filled with liquid and as it rises or falls, the pressure goes up or down. Others use an airtight container with a needle inside. As the air pressure goes up, the container is squeezed. Barometer

Anemometer An anemometer measures wind speed. This tools works like a pin wheel and has several cups that can spin. If the wind blow slowly, then the cups blow slowly. Anemometer

Hygrometer A hygrometer shows how much water vapor is in the air. This tells you the percent humidity, if the need points to 100, then the air is full of water vapor. Rain or snow is very likely. Hygrometer

Click ME! Weather Instruments

How do scientists make forecasts? A weather forecast is a prediction. It tells you what the weather might be in the future. They need data that they gather from their weather instruments. These are basic tools used by forecasters, but they also use computers and complex tools. How do scientists make forecasts?