2. Describing Weather What factors do we use to describe weather?

3. What is weather?  Weather is the atmospheric conditions, along with short-term changes, of a certain place at a certain time. Weather  Weather can change quickly or be the same for several days in a row.  BrainPop

4. What factors do we use to describe the weather?  Temperature  Precipitation  Air pressure  Wind  Humidity  Clouds

5. Temperature  Air temperature- the measure of the average kinetic energy of molecules in the air.  Molecules in warm air move faster than molecules in cold air.

6. Precipitation  Precipitation is water, in liquid or solid form, that falls from the atmosphere. Precipitation

7. Air Pressure  Air pressure- the pressure that a column of air exerts on the air, or surface, below it. Air pressure  Air pressure is measured with an instrument called a barometer.

8. Wind  As air moves from areas of high pressure to areas of low pressure, it creates wind.  Fun fact  The fastest wind speed recorded to date is 511 km/h  Recorded in Oklahoma as a tornado in 1999  Can pavement from roads and sounds like the roar of a jet engine

9. Humidity  Humidity- The amount of water vapor in the air is called. Humidity  When the humidity is high, there is more water vapor in the air.  The amount of water vapor present in the air compared to the maximum amount of water vapor the air could contain at the temperature is called relative humidity. relative humidity

10. Dew Point  The dew point is the temperature at which air is fully saturated (full of water) because of decreasing temperatures while holding the amount of moisture constant.dew point  When the temperature decreases, the air can hold less moisture  If the temperature is above freezing, dew forms/ below freezing, frost forms

11. Clouds  How do clouds form?  BrainPop