Vocab
Large body of air with the same temperature, humidity, and density.
Air mass
The 2 factors determine the temperature of an air mass
LATITUDE and ALTITUDE
What is the relationship between Relative Humidity and Temperature?
When temperature INCREASES, relative humidity DECREASES
What 2 factors does density depend on?
Mass and volume
The angular distance North or South of the equator.
Latitude
How does LATITUDE affect the temperature of a location?
Near the equator (0 degrees latitude), the sun’s rays are concentrated on one small area, where sunlight hits DIRECTLY with the most intensity.
Near the poles (90 degrees N or S latitude), the curve of the earth changes the angle of sunlight- the sun’s rays hit INDIRECTLY and are spread out over a larger area.
What are 2 things that relative humidity depends on?
Temperature and the amount of water vapor.
Why does hot air rise up?
It is less dense than the surrounding air.
A measure of the amount of matter (molecules) in a substance or object.
Mass
Which location would be hotter and why?
A= 5°N B= 35°N C= 60°N
A = 5°N, because this location is closer to the equator where the sun's rays hit more directly.
What is 1 thing that might increase the Relative Humidity in a HOT air mass?
A body of water can evaporate into water vapor, which puts more gas molecules in the air.
How does air become less dense?
Thermal energy energizes the air molecules so they travel further than before, which makes the volume (of the object) bigger. A larger volume decreases the density and it rises up.
PERCENTAGE of water vapor in the air.
Relative Humidity
Why is earth’s surface warmer than the atmosphere?
Most gas molecules stay closer to earth’s surface. As thermal energy leaves earth’s surface, it hits those molecules and becomes trapped.
With fewer gas molecules higher in the atmosphere, there is less trapped heat.
What is 1 thing that might increase the Relative Humidity as an air mass gets COLD?
The air mass cools down, the molecules lose energy, and the air mass decreases in size. This means the air mass can hold less gas inside it than before.
A measure of the amount of matter in a certain volume of a substance.
Density
Why do air masses expand as they warm up?
As the air mass warms, the gas molecules inside gain energy and have EXTREMELY HIGH ENERGY. The gas molecules have so much energy that they push the air mass boundary, which makes the air mass bigger.
Why might Relative Humidity PERCENTAGE decrease with a warming air mass?
The percentage decreases because the ratio of water vapor in the air compared to how much water vapor the air can hold decreases.
For example, if 10 molecules can fit and there are only 5, then the relative humidity is 50% full. With a larger air mass that fits 20 molecules and there are only 5 inside, then the relative humidity is 25% full.
How do convection currents form in the air?
Rising hot air and sinking cold air create a loop where the hot air goes up, and the cold air comes down.