Meteorology - Temperature Flashcards
What is temperature a measure of?
Temperature is a measure of the level of molecular activity within a substance.
Is temperature a direct measure of heat energy?
No, temperature is not a direct measure of the amount of heat energy present.
Can small objects with high temperatures contain little heat energy?
Yes, very hot small objects can contain little heat energy.
Can large warm objects contain huge amounts of heat energy?
Yes, large warm objects can contain huge amounts of heat energy.
What happens to molecular activity at absolute zero (-273°C or 0 Kelvin)?
All molecular activity ceases, and the object contains no heat energy.
What happens to temperature when heat energy is added?
The temperature goes up.
What does the temperature increase depend on?
The temperature increase depends on the material being heated.
How do we define the units of heat energy?
By reference to the behavior of water.
What is a calorie (cal)?
The amount of heat needed to raise one gram of water by one degree centigrade (or one Kelvin).
How much does the temperature of 1 gram of water rise if 10 calories are added?
The temperature will rise by 10°C.
How much does the temperature of 100 grams of water rise if 10 calories are added?
The temperature will rise by 0.1°C.
Which substance has the highest ability to absorb heat among common substances?
Water.
What is specific heat?
The ratio of the amounts of heat required for the same temperature rise.
What is the specific heat of water?
1
What is the approximate specific heat of ice?
0.5
What is the approximate specific heat of rock?
About 0.25, depending on its composition.
How much energy is needed to raise the temperature of 1 gram of water by 1 degree Celsius?
One calorie.
How much energy is needed to raise the temperature of 1 gram of ice by 1 degree Celsius?
½ calorie.
How much energy is needed to raise the temperature of 1 gram of rock by 1 degree Celsius?
¼ calorie.
How does the specific heat affect oceans and land masses?
Oceans stay at a more or less constant temperature while night and day, winter and summer, but land heats up quickly and cools down quickly.
What is needed to loosen the bonds that hold molecules together and change solids to liquids and liquids to gases?
Energy is needed to loosen the bonds that hold molecules together and change states of aggregation.
What happens to the temperature when energy is input to change the state of aggregation?
The temperature does not rise; the energy remains hidden (latent).
How many calories are needed to change 1 gram of ice at 0°C to water at 0°C?
80 calories.
How many calories are needed to change 1 gram of liquid water to water vapour at 100°C?
540 calories.
What happens when 1 gram of water vapour condenses into water?
540 calories are released into the surroundings.
How many calories are released when 1 gram of water freezes to ice?
80 calories are released into the surroundings.
What are the latent heat of fusion and latent heat of evaporation?
Latent heat of fusion is melting/solidification and latent heat of evaporation is condensation.
How much total heat is needed to bring 1 gram of ice at -273°C to water vapour at 100°C?
857 calories (137 cal to bring ice to 0°C, 80 cal to change to water, 100 cal to bring water to 100°C, 540 cal to change water to vapour).
How much heat is released when water vapour changes back to water at 100°C?
540 calories per gram.
Can water evaporate at temperatures below 100°C?
Yes, but the process is slower and requires more calories.
What is sublimation in terms of state changes?
Sublimation is when water vapour goes straight to ice or ice goes to water vapour without passing through the liquid stage.
How many calories are involved in sublimation?
About 680 calories, the sum of the two normal stages.
How do cloud and fog droplets form?
By condensation of water vapour from the atmosphere onto small particles called condensation nuclei.
What role do condensation nuclei play besides forming cloud and fog droplets?
They affect the optical properties of the atmosphere and play an important role in atmospheric electricity.
When will droplet cloud formation occur in a dust-free sample of air saturated with water vapour?
When the air is rapidly expanded so that adiabatic cooling occurs and the expansion ratio is high enough to produce several hundred percent supersaturation.
At what level of supersaturation can condensation occur if particles are present in the air?
At much lower supersaturations (a few tenths of a percent).
What determines the effectiveness of a particle as a condensation nucleus?
Whether it is hygroscopic (water attracting) or hydrophobic (water repelling).
How can small water droplets be supercooled?
They can be supercooled to temperatures as low as -40°C.
What happens in the presence of freezing and sublimation nuclei?
The formation of ice crystals occurs at much warmer temperatures.
What is the energy impact of changes of state of aggregation?
The energy released by changes of state of aggregation is extraordinary.
Give an example of the impact of latent heat of condensation.
Over the Amazon basin on a typical day, rising moist air forms convective clouds aloft and heavy rain falls, releasing latent heat of condensation, which can raise the mean temperature of the troposphere overhead by 10°C.
What is a powerful factor involved in the global movement of heat energy?
The process of evaporation and condensation.
What is insolation?
Insolation is a measure of solar radiation energy received on a given surface area in a given time.
How is radiation defined?
Radiation is defined as the emission and propagation of energy in the form of rays or waves; the energy radiated or transmitted in the form of rays, waves, or particles; and a stream of particles or electromagnetic waves emitted by the atoms and molecules of a radioactive substance as a result of nuclear decay.
How is solar energy created at the core of the Sun?
Solar energy is created when hydrogen atoms are fused into helium by nuclear fusion.
What is the average temperature of the Sun’s photosphere?
About 5800 Kelvins.
In which bands does the Sun emit electromagnetic radiation?
Most radiation is emitted in the visible band centered at 500 nm, but the Sun also emits significant energy in the ultraviolet and infrared bands, and small amounts of energy in the radio, microwave, X-ray, and gamma ray bands.
What is the total quantity of energy emitted from the Sun’s surface?
Approximately 63,000,000 Watts per square meter (W/m² or Wm⁻²).
What happens to the energy emitted by the Sun?
It passes through space until it is intercepted by planets, other celestial objects, or interstellar gas and dust.
How long does the trip from the Sun’s surface to the Earth take?
About 8 minutes.
What happens to a lot of the Sun’s energy as it reaches the atmosphere?
It is diverted, scattered, and reflected high in the atmosphere, and much of the ultraviolet is absorbed in the ozone layer.
How much of the Sun’s energy is scattered or absorbed in the troposphere?
About 15%.
How does the Sun’s radiation affect the Earth and troposphere?
The Sun’s radiation passes through the troposphere to heat the Earth, and the Earth then heats the troposphere.
What factors influence the intensity of radiant energy from the Sun that hits the Earth?
The angle of arrival, which depends on the Earth’s latitude, the season, the tilt of the Earth’s axis in relation to the Sun, and the time of day.
How does the intensity of radiation change when it hits different points on the Earth’s surface?
The same intensity of radiation covers more surface area at points A and C than at point B, reducing the intensity of radiation on the surface at A and C.
What additional factor reduces the intensity of radiation on the Earth’s surface?
The extra distance that radiation at A and C has to pass through the atmosphere slightly reduces the intensity on the surface.
What happens to radiation when it arrives at the Earth’s surface?
Some of it is absorbed, and some is reflected back out to the troposphere and to space.
