LESSON 5 - ACTIVITY 3 - WIND AND PRESSURE
Objectives
Materials
Background Information
Key Questions
Vocabulary
Procedure
Evaluation
Objectives
- Plot wind and pressure on weather map
- Review how sky cover can affect temperature
Materials
- local weather map from newspaper
- outline map of the US
Background Information
In this activity, students will add wind direction and pressure readings to their map and spreadsheet. The symbol for wind on a weather map is a straight line extending from the edge of the sky data symbol that points in the direction that the wind is coming from. For example, if the wind is blowing from the East, the wind symbol (a straight line) will be drawn extending right from the sky data symbol.
Wind barbs image NOAA
Pressure readings are always found in the upper right corner of the station data. Meteorologists measure barometric pressure in millibars. The example below shows a weather station reporting mostly cloudy skies, a southwest wind blowing at 25 knots and a barometric pressure reading of 998 millibars.We will plot barometric pressure as inches of mercury as this is more familiar to us. Use the link here to access an online conversion site to convert the pressure readings from millibars to milligrams of mercury. http://www.onlineconversion.com/pressure.htm. Enter the millibar reading in the field at the top of the form. Choose millibars on the left side, and inch of mercury on the right side, then click on convert.
We will plot pressure readings using two whole numbers and two decimal places. The pressure reading will generally be between 29 and 30 unless a strong storm is approaching. Pressure readings represent the height of a column of mercury (in inches) that is in an instrument called a mercurial barometer. A barometric pressure reading of 29.50 represents a column of mercury 29 and a half inches high.
Key Questions
- How is air pressure measured?
- How do winds affect temperature?
Vocabulary
- cloud cover
- pressure
- barometer
- millibar
- inches of mercury
Procedure
- Review how air pressure is measured. Explain the online conversion tool and why the students will be using it. Also explain that pressure readings will be recorded as two whole numbers and two decimal places.
- Explain how wind direction is recorded and its position to the sky symbol.
- Allow your students sufficient time to access the internet to collect data for wind direction, air pressure, and to perform their conversions for the 13 weather stations. They should become more familiar with the internet site the more times they access it, resulting in less time spent collecting data.
- Students will record wind and pressure data on their weather map and in their spread sheet.
- Discuss with your students how wind or clouds affect temperatures and pressure readings.
- Have your students write their responses in their journal.
Evaluation
Students will be able to interpret wind and pressure readings from real-time weather data and convert this information to symbols used on weather maps.
