Air pressure changes with temperature and elevation. Warmer air is less dense and rises, creating low pressure areas, while cooler air is denser and sinks, creating high pressure areas. Wind is caused by air moving from high to low pressure areas. Air pressure is measured with a barometer, wind direction with a wind vane, and wind speed with an anemometer. For a set of daily wind speed data, the range is the difference between the highest and lowest values, the median is the middle number after sorting, and the mode is the number that occurs most frequently.

1. How Does Temperature Affect Air Movement?You’re riding an elevator and suddenly you can hardly hear. You swallow. POP! Oh, much better. What caused your ears to pop? It’s called air pressure.

2. Air Pressure: the amount that air presses or pushes on anythingYou usually do not notice air pressure, but you do notice its effectsAir Pressure and Wind

3. As you travel higher above the earth, the air pressure changesHigher=Less Pressure

4. Temperature also changes the higher you travel.The Earth’s surface heats the air.Farther From Earth = Cooler TemperatureTemperature: 34ºFTemperature: 54ºFTemperature: 76ºF

5. As the air near the surface of the earth becomes warmer, the air particles move farther apart.The air become lighter and risesThis is when a low-pressure area formsLow Air Pressure

6. Cole air s heavier than warm air.It’s air particles are packed closer together and push down harder.This is when a high-pressure area forms.High Air Pressure

7. Air moves from a place with high pressure to a place with low pressure.Air moving is called wind.When the cooler air from a high-pressure area sinks toward the earth, it causes wind.That’s why you will feel a cool breeze…even on a warm, summer day.Wind

8. BarometerMeasuring Air Pressure

9. Wind VaneMeasuring Wind Direction

10. AnemometerMeasuring Wind Speed

11. What causes wind?Let’s Review!Wind is caused by air moving from a high-pressure area to a low-pressure area.

12. How is air pressure measured?Air pressure is measured by a barometer.

13. How do scientists measure wind direction?Scientists measure wind direction with a wind vane.

14. How do scientists measure wind speed?Scientists measure wind speed with an anemometer.

15. Suppose the daily high wind speeds in a place for a week are 30 kph (kilometers per hour), 10 kph, 30 kph, 20 kph, 15 kph, 25 kph, and 40 kph. What is the range, median, and the mode of the wind speeds?Range, Median, and Mode

16. Order the numbers!10, 15, 20, 25, 30, 30, 401st Step

17. Find the range!40-10 = 30Range = 30 kph2nd Step

18. Find the median10, 15, 20, 25, 30, 30, 40Median = 25 kph3rd Step

19. Find the mode10, 15, 20, 25, 30, 30, 40Mode= 30 kph4th Step