Weather Flashcards
What is a weather
Day to day state of atmosphere short term variation
What is a climate
Weather of a place averaged over a period of time
What are clouds
Clouds are accumulation of water droplets or solid ice crystals in the earth troposphere
How do clouds form
Clouds form when hot air moist vapour rises up and causes the water vapour in it to cool
Then the water vapour condense in the air water droplets at the highest altitude form of ice crystal in the cloud
What does Stevenson screen contain
A shelter from rain, snow and high winds but also leaves and animal particularly wet and dry bulb thermometer to record humidity and air temperature
Feature of Stevenson screen
Made of wood - to prevent absorption and conduction of heat
Painted white or silver grey- in order to reflect sunlight
Stand 1.2 metre- avoid the influence of the ground condition
The side and floor are made of slabs to allow free circulation of air and to keep of directed sun rays
Stands on grass covered ground for same amount of reflection
Siting of Stevenson screen
Placed far away form buildings or obstables to avoid any interference
The roof is slanting to avoid rain water
Rain gauge
Precipitation
The rain gauge is usually anchored in the ground with the top of the gauge around 30 cm above the ground surface to ensure that rain splash doesn’t affect the results
The depth of the
Wind vane
It consist of a light wooden structure having a pointed face with an arrow towards the direction from which wind blows and a broad face opposite to it
—> structure rotates on a vertical rod freely (compass direction)
Maximum and minimum thermometer
—> max thermometer contains mercury
-min thermometer contain alcohol
- as the temp rises, Mercury expand and pushes up the metal index and when it cools the Mercury contract and index is left in place at highest temp
- as temp falls, alcohol contracts and pulls metal index with it; but as metal index expands it flow past index leaving at lowest temp
Both index read from the bottom every 24 hours
Thermometer should be 1.2 m above ground to avoid heating and cooling by the ground
Must be shaded , out by direct sunlight
Must be away from buildings that can radiate heat
Wet and dry thermometer
The dry thermometer is normal records actual air temp
The wet bulb is covered in a wet cloth that is kept constantly wet.
—> as water evaporate it uses energy and causes the wet bulb to cool
The temp of the dry bulb minus the temp of the wet bulb gives us the depression of the wet bulb reading that can be used on a table to measure relative humidity
Amount of water vapour in the air
Cold air= low humidity
Warm air= high evaporation and high humidity
Sunshine recorder
Sunshine recorder
In the device a glass sphere concentrate sunlight into the card and the amount of scorching on the card records the anoint of sunlight that had fallen (measure the intensity sunshine)
- burns timeline
- traces sunshine not hours of daylight
- the glass ball focus light
- this burns a line onto the card
Where sun will not be blocked by building trees
Mercury barometer
The pressure of the air in the barometer forces the Mercury up the tube . The reading is taking from the scale at the height it reached from the scale at the height it reached
Inverted glass tube standing in a bath of Mercury
Measure atmosphere pressure
Aneroid barometer
An android barometer has a corrugated metal box inside it that can expand when pressure is low and contract when pressure is high
This moves a pointer dial that allows you to read the air pressure in millibar
How a student could observe and record cloud types and amounts at the school
Choose set time
Observe at several times each day
Look up the sky
Identifying cloud types using a identification chart
Estimate cloud cover
Record names and cloud cover in okras
