Presentation on theme: "Chapter 2, Lesson 3. A weather forecast is a prediction of weather conditions over the next 3 to 5 days. A meteorologist is a person who observes."— Presentation transcript:
A weather forecast is a prediction of weather conditions over the next 3 to 5 days. A meteorologist is a person who observes and collects data on atmospheric conditions to make weather predictions.
Atmospheric conditions that meteorologists need to measure are: 1. Air pressure 2. Humidity 3. Precipitation 4. Temperature 5. Wind speed 6. Wind direction Meteorologists use special instruments to collect data on weather conditions.
Weather balloons that carry electronic equipment that can measure weather conditions are used to collect atmospheric data above Earth’s surface.
Instruments used to measure weather conditions: 1.Thermometer is used to measure air temperature. When air temperature increases, the liquid inside the thermometer expands and moves up, showing higher reading. When air temperature decreases, the liquid shrinks and moves down the tube.
Instruments used to measure weather conditions: 2. Barometer is an instrument used to measure air pressure. It consists of a glass tube sealed at one end and placed in a container full of mercury. As air pressure increases, it pushes the mercury inside the container, which causes moving up of the glass tube.
Instruments used to measure weather conditions: 3. Windstock or wind vane is an instrument used to measure the wind direction. It is a cone-shaped cloth bag opens at both ends. Wind enters through the wide end and leaves through the narrow one.
Instruments used to measure weather conditions: 4. Anemometer is an instrument used to measure wind speed. It consists of 3-4 cups connected to a pole. The wind pushes the hollow sides of the cups causing their motion and this sends a weak electric current that is measured.
Instruments used to measure weather conditions: 4. Radar is an instrument used to find the location, movement, amount and type of precipitation.
Weather satellites that orbit Earth provide images of weather system. Satellites are used to show storms, winds, humidity, and temperature at different altitudes.
Weather maps The National Center of Meteorology and Seismology collects and analyze weather data, then produces weather maps based on the information gathered from weather stations across the country.
Weather maps Station model is a small model circle that shows the location of the weather station.