Do You Understand Temperature?
Temperature is among one of the most important terms used when it comes to studying the atmosphere, its processes and the effects within and among its surrounding systems. This term simply means the numerical measurement (in ‘degrees’) of hot or cold absorbed and radiated by any substance or point. This measurement varies from place to place and time to time.
There are different ways of measuring temperature, but they are all denoted by temperature scales such as degrees Celsius (°C), degrees Fahrenheit (°F) and/or Kelvin (K), among the most widely and currently used. Some of the other types of temperature scales include Rankine, Delisle, Newton, Reaumur, Planck and Romer, among others, but some of these are outdated.
The temperature of a specific point on the surface of the earth will vary depending on factors such as:
• The distance from the sun
• Day and night length
• Density of clouds or air pollution
• Distance from the sea and how far above it is from sea level
• Physical features - type of surface, shape, aspect, etc.
• Presence or absence of winds
For example, the temperature of the air will vary depending on the season, night or day. Also, some elements will have more radiation absorbed or released depending on their density and colour.
Do You Understand Rainfall?
Water is an odourless, colourless substance made of atoms of hydrogen and oxygen that, bound together, make up molecules of H2O. These molecules move around and rearrange themselves depending on the temperature they are exposed to, forming one of the three main states listed below:
- SOLID - Ice
- LIQUID – Water
- GAS – Water vapour
No matter which states these molecules are found, they are constantly moving or vibrating. Molecules of ice are the ones most tightly bound together. When temperature rises, these molecules absorb heat and begin to separate (melting process begins), resulting in a liquid state.
If temperature keeps rising, the water molecules go through faster more vigorous movements, creating a wider space between molecules (evaporation), until the bonds have completely broken and the molecules can move around freely, resulting in a gaseous state (if the liquid is pure and at standard atmospheric pressure (1atm), then ‘boiling point’ should occur at 100oC and over). Some of the water molecules, such as those that have absorbed higher temperatures, are able to escape the surface.
Conversely, just as molecules absorb heat, they are also able to release it and form one of three states. The process from gas to liquid releases the same amount of energy (calories) as to when it is being absorbed, but going through a process of condensation as opposed to evaporation. During condensation, the molecules experience a type of ‘compression’ due to the cooling down occurrence caused from the energy that is being released.
This can relate to the formation of cloud droplets when there is enough moisture in the air; if the amount of moisture is too high, then storm clouds may begin to form. This same way, when the molecules are in a liquid state and the temperature decreases, the molecules release energy (cool down) and the process of freezing begins. During this transition phase, the molecules will continue to ‘crystallise’ (solidify) until ice is formed (if the liquid is pure and at standard atmospheric pressure (1atm), then ‘freezing point’ should occur at 0oC and below).