Module 3 (Heat and the Atmosphere)

1. How does one convert between the units of temperature?

°F = (9/5 * °C) + 32

°C = (°F – 32) * 5/9

°K = °C + 273

1. What is the definition of temperature?

Temperature is the measure of the average kinetic energy in the molecules or atoms of a substance

1. Why is evaporation a cooling process?

When there is more kinetic energy, water molecules evaporate because they are faster and escape easily and the average motion of the molecules left behind  decreases. This lower energy remains suggests a lower water temperature hence it being a cooling process. 

Why is condensation a warming process?

Higher energy gas phase molecules combine into power energy liquid phase. Energy in those gas water vapor molecules is released into the atmosphere during condensation. Hence it being a warming process.

1. When is latent heat released to the environment, and when is it taken from the environment?

Latent heat is released into the environment when a substance goes from gas to liquid (condensation) and latent heat is taken from the environment when a substance goes from liquid to gas (evaporation).

1. What are the three methods of energy (heat) transfer in the atmosphere? Be able to define and give a real-world example of each.

Conduction: transfer of energy in a substance by molecular excitation without any net external motion. E.g.: metal rod over a flame. The flame heats up the end of the rod, molecules get warm and transfer through the rest of the rod. 

Convection: transfer of heat by the mass movement of a fluid usually occurs vertically. External force, atoms move from a hot region to a cooler region taking up the energy (heat) with them. EG boiling water, water heats in middle and rises displacing cold water on top. 

Radiation: transfer of heat by electromagnetic waves. Doesn’t need atoms/molecules to propagate, no external motion. Fireplaces feeling the warmth.  

What must be true for an object to emit radiation? What are examples of objects that emit radiation?

It must have a temperature greater than 0K. E.g. Humans have temperature, or the sun or earth.

1. What is the strength and wavelength of radiation emitted by the Sun and Earth?

The wavelength of the sun is called shortwave, specifically 0.5um, at its peak. The wavelength being visible wavelength. For the Earth, it has infrared wavelengths with longer waves, and at its peak 11um. In comparison to each other, the sun has a higher intensity radiation compared to Earth.

Why is the sky blue during the day and appear orange/red around sunrise/sunset

During the day when the sun is overhead, some sunlight reflects off air particles, and scatters. Air molecules are smaller than the wavelengths of visible light and are more effective in scattering shorter (Blue) wavelengths that longer (Red). In morning/evening, the shorter (blue) wavelengths get completely scattered away and only the longer (red) wavelengths remain.

1. What is the definition of albedo?

the ratio of light reflected by a surface to the light it receives