Temperature and heat (thermal energy) are related concepts but have distinct definitions, units, and roles in thermal dynamics:
Definitions:
Temperature is a measure of the average kinetic energy of the particles in a substance. It indicates how hot or cold a substance is but does not measure the total energy in the substance and does not take into account the mass of the substance.
Heat (thermal energy) refers to the transfer of energy from one object to another due to a temperature difference. It is the total amount of thermal energy transferred and is dependent on the temperature, mass, and type of substance.
Units:
Temperature is measured in degrees Celsius (°C), Kelvin (K), or degrees Fahrenheit (°F).
Heat is measured in joules (J) in the International System of Units (SI). Other units include Calories (C) or British thermal units (BTU).
Roles in Thermal Dynamics:
Temperature determines the direction of heat transfer: heat flows from a region of higher temperature to a region of lower temperature until thermal equilibrium is reached.
Heat is the amount of energy in transit that flows between systems, affecting the temperature and potentially changing the state of a substance (e.g., melting, boiling) without necessarily changing its temperature during phase transitions.
Temperature indicates how hot or cold a substance is, and heat describes the energy transfer between substances as a result of temperature differences.
Thermal Insulators
One way to retain your own thermal energy on a cold day is to wear clothes that trap air. That’s because air, like other gases, is a poor conductor of thermal energy. The particles of gases are relatively far apart, so they don’t bump into each other or into other things as often as the more closely spaced particles of liquids or solids. Therefore, particles of gases have fewer opportunities to transfer thermal energy. Materials that are poor thermal conductors are called thermal insulators. Down-filled snowsuits are good thermal insulators because their feather filling traps a lot of air
Thermal Conductors
Conduction is the transfer of thermal energy between particles of matter that are touching. Thermal conduction occurs when particles of warmer matter bump into particles of cooler matter and transfer some of their thermal energy to the cooler particles. Conduction is usually faster in certain solids and liquids than in gases. Materials that are good conductors of thermal energy are called thermal conductors. Metals are especially good thermal conductors because they have freely moving electrons that can transfer thermal energy quickly and easily.
What is convection?
Convection is the transfer of energy as heat by the movement of a liquid or gas.
Convection occurs when a cooler, denser mass of gas or liquid replaces a warmer, less dense mass of gas or liquid by pushing it upward.
When water is boiled, the water moves in roughly circular patterns because of convection.
This motion is due to density differences that result from temperature differences.
The motion is called a convection current.
Thermal radiation is the transfer of thermal energy by waves that can travel through air and even through empty space at the speed of light. When the waves of thermal energy reach objects, they transfer the energy to the objects, causing them to warm up. This is how the fire warms the hands of someone sitting near the bonfire. This is how the sun’s energy reaches Earth. The energy travels through 93 million miles of empty space between the sun and the earth in just over 8 minutes.
Radiation: heat transfer in the form of electromagnetic waves, including waves.
bsolute Temperature
Absolute temperature is temperature on a scale where 0 is absolute zero. At absolute zero, atoms and molecules have minimum energy.
Kelvin
Rankine
Celsius
Fahrenheit
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