Part 1 - what is snow? Flashcards
What shape are snowflakes?
Hexagonal
What are the size of snowflakes dependent on?
The temperature and amount of water vapour available at the time of development
At what temperature can snowflakes form?
-40 degrees
What percentage of the earth do snowflakes cover?
23%
How do snowflakes form?
Ice crystals form around a small particle of dust or chemical substance in the air.
If the air is humid the the crystals tend to grow more rapidly, develop branches and clump together. In colder, drier air the particles remain small and compact
Define the term ‘snow’
It is the solid form of water that crystallises in the atmosphere
What is air from ear the earths surface made up of approximately?
Nitrogen
Oxygen
Argon
Very small traces of other gases including carbon dioxide and water vapour
What percentage of nitrogen makes up air?
78%
What percentage of oxygen makes up air?
21%
What percentage of argon is air made from?
1%
Up to what percentage of water vapour may air contain in hot tropical rain forests?
4%
What happens to the molecules and pressure of the air with altitude?
It decreases
How thick is the earths atmosphere?
It is a difficult question to answer but it is said to be about 100 km
What thickness of the atmosphere does weather take place in?
15 km of the earths atmosphere
Why does a helium balloon rise?
Helium is lighter than air
In a video a helium balloon was sent into the atmosphere, as it rose it expanded to around 3 times its size, why did it expand?
The balloon expanded because of the pressure of the helium gas inside the balloon was higher than the pressure of air outside the balloon
Why did a helium balloon that was sent into the atmosphere fall back down once the ballon had burst?
Because of the force of gravity
What is the abbreviation for volume?
V
What is the abbreviation for mass?
m
In mathematical terms what is the abbreviation for density?
p
In mathematical terms if two symbols are put next to each other what does this mean?
It is accepted that this means that they should be multiplied together
On average how much does the temperature drop every 1000 m of ascent?
6 degrees Celsius
Though these values vary considerably with location, season and time of day
Assume the temperature drops 6 degrees for every 1000 m of ascent. If it is 15 degrees at sea level(0m altitude). What is the atmospheric temperature on the summit of Mount Everest (8848 m) ?
There are 8.848 sets of 1000 m. 8.848 multiplied by 6 degrees = 53.088 degrees 15 - 53.088 = 38.088 degrees Rounded to 1 sig fig -40 degrees
What is the troposphere?
It is the lowest region of the atmosphere
It is bounded by the earth beneath and the stratosphere above
10-18km
Characterised by decreasing temperature with increasing altitude
Which layer of the atmosphere are most of the weather and cloud systems held?
Within the troposphere
What is the lowest temperature that is reached in the troposphere?
-57 degrees Celsius
What are the three main transfer of heat?
Thermal conduction
Convection
Radiation
How is heat transferred through thermal conduction?
This happens when two objects are in contact with each other.
Heat can be transferred from an object at one temperature to an object at a lower temperature when the two objects come into contact with each other.
How is heat conducted from the ground to the atmosphere?
Air is a poor heat conductor, but heat is nevertheless transferred by conduction from the ground to the lowest layer of the atmosphere when the ground is hotter.
Explain how convection heat transfer works?
The bottom part to a heat source heats up first, as it gets hot it rises and liquid/gas moves down in its place to warm it up.