8-1: Water in the Atmosphere in the... · 8-1: Water in the Atmosphere Summary •Water vapor in the atmosphere turns into liquid when too much is in the air – called condensation.

8-1: Water in the Atmosphere

6th Grade Earth Science

8-1: Water in the Atmosphere

• The water cycle is the continuous movement of water between the Earth’s surface and the atmosphere.

Water Cycle

8-1: Water in the Atmosphere

• Evaporation is the process by which water molecules in liquid absorb the sun’s energy and escape into the air as water vapor.

Evaporation

8-1: Water in the Atmosphere

• Humidity is the amount of water vapor in the air.

• Air’s ability to hold water depends on its temperature.

• Hot air holds more.

• Cold air holds less.

Humidity

8-1: Water in the Atmosphere

• Relative Humidity is how humidity is usually reported on weather reports.

• It is the percent of water in the air compared to the maximum it can hold at a given temperature.

Relative Humidity

8-1: Water in the Atmosphere

• A sling psychrometer is used to measure relative humidity.

• A wet bulb and a dry bulb thermometer measures two temperatures.

Measuring Relative Humidity

8-1: Water in the Atmosphere

• The dryer the air, the bigger the difference between the two temperatures.

• Wet bulb is colder since evaporation cools the thermometer.

8-1: Water in the Atmosphere

• DON’T COPY

• Sample table to figure relative humidity based on sling psychrometer.

8-1: Water in the Atmosphere

• DON’T COPY

• Easier way to find out relative humidity – not as accurate though - HYGROMETER

8-1: Water in the Atmosphere

• Clouds form when water vapor in the air condenses into millions of water droplets or ice crystals.

How Clouds Form

8-1: Water in the Atmosphere

• Condensation happens when the temperature cools down.

• AND … there is a small particle of dust, salt, or something to condense on.

8-1: Water in the Atmosphere

• If condensation happens on an object, we call it dew.

8-1: Water in the Atmosphere

• If it is frozen condensation, we call it frost.

8-1: Water in the Atmosphere

• We call the temperature that condensation occurs the dew point.

• The dew point is always changing.

What temperature will dew or frost form?

8-1: Water in the Atmosphere

• Graphs from Luiseno’s Weather Station.

• Live data

8-1: Water in the Atmosphere

• Graphs from Luiseno’s Weather Station.

• Live data

8-1: Water in the Atmosphere

• Clouds form when the temperature drops to the dew point – at the base of the cloud.

Condensation in Clouds

8-1: Water in the Atmosphere

• Timelapse Clouds

• Canary Islands

• Supercell

Time Lapse of Clouds

8-1: Water in the Atmosphere

• Clouds are classified by shape and altitude.

• Shape: Cirrus - wispy Cumulus - fluffy Stratus - flat layer

• Altitude: Alto - high

Types of Clouds

8-1: Water in the Atmosphere

8-1: Water in the Atmosphere

• Cirrus – High level clouds of ice crystals.

• Cumulus – Low level puffy clouds

• Stratus – Low level flat layer of clouds covering the sky

8-1: Water in the Atmosphere

• Altocumulus – High level puffy clouds

• Altostratus – High level flat layer of clouds covering the sky

• Fog - Ground level clouds.

8-1: Water in the Atmosphere Summary

• Water vapor in the atmosphere turns into liquid when too much is in the air – called condensation.

• Cooling the air causes condensation to form on tiny particles of dust or salt.

• Condensation causes the different kinds of clouds to form.

• Some wispy, puffy, or flat. • Some high, low, or on the ground.