2.4 Weather Flashcards
Weather
The atmospheric conditions ins a specific place and time.
How does a Stevenson’s screen provide an accurate reading of temperature? (4)
Painted white to reflect the sun
Slatted sides to let the air circulate
Legs 1m long to avoid radiation from the ground.
Placed on short grass for same amount of reflection.
Explain how a rain gauge works
It has a fixed diameter so readings can be compared
Water passes through a funnel and is collected in a container that is emptied every 24h.
Rain is measured in mm.
Why is a rain gauge above ground level?
To avoid splashes or surface water from getting in.
Anemometer
Measures wind speed
Explain how a sunshine recorder (Heliograph) works
Glass ball focuses light from the sun so that it ‘burns’ a timeline onto a card.
Explain how does the Max/min thermometer works
As temp. rises, mercury in the max thermometer expands pushing up a metal index that remains there.
As temp. falls, alcohol in the min. thermometer contracts and pulls with it a metal index that remains there.
Wet and dry bulb thermometer (hygrometer) - How does it work?
Dry bulb is a normal thermometer that measures air temp.
Wet bulb is covered with a cloth that is connected to a reservoir of water. This water evaporates and therefore cools the bulb making it read lower temperatures.
How does a barometer work?
Contains a vacuum chamber and whenever air pressure rises/falls, the chamber contracts/expands, making a lever change the reading in the dial.
How does a wind vane work?
Arrow head points to where the wind is coming from-
