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Temperature is the property of an object, a surface, or a system that determines whether there will be a displacement of heat from that object or system from or to another object or system in its vicinity and in which direction the heat will move.
In general, there are two methods for quantifying thermodynamic temperature. An empirical method consists of taking two or more temperature-dependent and reproducible events and specifying fixed points on a scale of values for these events. The other method used to determine temperature measures the amount of heat that flows between objects or systems under different conditions.
Characteristics of Temperature
Temperature can be dry, humid, or radiant – While dry temperature determines the warmth of air using a thermometer without exposing it to radiation or moisture, the radiant temperature is the average measure of the heat emitted and absorbed by the substances in the environment. The humidity of temperature on the contrary measures the water present in the air compared to the amount of water vapor that the air can retain at that point.
Temperature is affected by altitude – As higher altitudes reduced atmospheric pressure, air cannot hold more particles resulting in a low temperature.
Latitude modifies temperature – Latitude is another factor that modifies temperature because, in Equator, the surface of the earth receives the sun’s rays perpendicularly. At the poles, these rays impact tangentially and for a lesser time. Thus, the greater the distance from the equator, the lower the temperature.
Instruments Used to Measure Temperature
A thermometer is a commonly used instrument to measure temperature, but depending on the use, the unit of measurement, and the required degree of amplitude, various types of thermometer needs to be used. The various types of thermometers are as follows:
- Liquid thermometer – The liquid used in these thermometers is usually mercury or colored alcohol and their measuring ranges fall between -10° C to 110° C. These thermometers have larger measurement amplitude and greater precision than the other types of thermometers.
- Gas thermometer – These thermometers come with a measuring range between -150° C and 600° C approximately. Gas thermometers are highly accurate, but they are less used compared to other thermometers due to complications in their use.
- Pyrometers – This type of thermometer make use of radiation to measure high temperatures of up to 4000°C and higher.
- Platinum thermometers – Also known as Resistance thermometers, these types of thermometers measure between -200° C and 1000 °C, with a very high accuracy level.
How does Temperature Affect Surface Tension?
The effect of temperature on surface tension is responsible for creating a film or a layer at the periphery of a liquid, thereby contracting it. The cohesive forces create an adhesive action in the molecules of a liquid and this is the reason why a small amount of water doesn’t fall off a glass and droplets of spherical shape are created.
What is surface tension?
The word ‘Tension’ refers to a force, something that exerts pressure. To put it in simple words, surface tension is a phenomenon that forms a kind of invisible film around a liquid, like an elastic membrane, preventing it from spreading. This tension is created because of the inequality of forces between its interior and surface molecules.
The phenomenon of surface tension is the reason that water doesn’t fall off when little water is dropped on a glass slide. The water takes the shape of a drop and looks like a soft solid. This physical phenomenon occurs in all liquids (to a greater or lesser degree) and is capable of temporarily modifying their behavior.
How does it arise?
The surface tension is more intense in liquids with high intermolecular forces because of the force of cohesion.
Intermolecular forces create an attraction between the atoms that form a molecule. This force defines properties such as melting and boiling points. The attractions between molecules due to the effect of temperature can be of three types:
- Dipole-induced: It is an attraction occurring between nonpolar and polar molecules. This type of attraction is weak in strength.
- Dipole-dipole: This type of attraction takes place between polar molecules and features an average strength.
- Hydrogen Bonding: It happens in molecules that have H attached to F, O or N. A hydrogen-bonding attraction is very high in strength.
The same molecule has a positive and a negative side. This causes several water molecules to align (opposites attract) and maintain a powerful attraction that binds them together, called the Cohesion Force.
What is the effect of temperature?
The temperature in physics is a measure of the vibration of the molecules. Based on the temperature, the surface tension of fluids increases or decreases. It usually decreases with an increasing temperature and almost becomes zero at extremely high temperatures.
This is because a high agitation of the molecules due to increased temperature pushes the molecules from each other thereby decreasing the forces of attraction.
Conclusion
Thermodynamics is a discipline of Physics that mainly studies the transformation of thermal energy into work. Temperature and its effects form an integral part of thermodynamics. The direct use of the principles of temperature in internal or external combustion engines makes it an important theory for car, truck, and tractor engines, turbines with application in airplanes, etc.
