2. Weather! Chapter 7 sections 1&4 Measuring and recording! Meteorologists use a variety of weather instruments to more accurately forecast the weather. Write down the ones you know.

3. Measuring Relative Humidity The amount of moisture that is in the air is a major factor that influences our weather. Moisture in the air is known as humidity Relative humidity is the comparison of the amount of moisture present in the air at a certain temp. compared to the amount it COULD have in the air at that temp. This comparison is given as a percent (%) Do you know what tool is used to measure Relative Humidity????

4. Relative Humidity Psychrometer measures in percentages (%) Hygrometer measures in percentages (%)

5. Measuring Rain Meteorologists keep up with and record the amount of precipitation that falls. These measurements are given in inches or centimeters. Why would meteorologist want to keep with that?

6. Rainfall A Rain gauge is used to measure the amount of precipitation that has fallen.

7. Measuring Wind Speed Wind (air) speed is also an influence in the weather. It could signify a major temperature change, which results in storms or severe weather. Wind speed is measured in Mph (miles per hour) or kmph (kilometers per hour)

8. Wind Speed An anemometer is used to measure wind speed. As the wind spins the cups the turning is transmitted to dials that show how fast the wind is blowing.

9. Measuring Air pressure As different air masses move across the regions of our Earth they produce characteristic types of weather. These air masses are known as either Cyclones (low pressure systems) or Anticyclones (high pressure systems)

10. Air pressure Barometers measure air pressure. Mercury Barometers measure the amount of pressure the air exerts on a column of Mercury, the level of mercury goes up when the air pressure is high and goes down when its low. Barometric pressure can be measured in inches, millimeters, or millibars.

11. Air pressure Aneroid Barometers contain NO liquid. It depends on a vacuum box to movie in and out as air pressure changes. As the vacuum box moves in and out the movement causes a dial to fluctuate. This barometer pressure is also measured in in, mm, millibars

12. Measuring Temperature What tool measures the temperature of the air? –Thermometer What is the temperature measured in? –Celsius C –Fahrenheit F